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doc/tutorial/apa.html doc/tutorial/apb.html doc/tutorial/apc.html
Thu Jul 24 15:46:02 MDT 2003 John Fleck <jfleck@inkstain.net> * doc/tutorial/apa.html * doc/tutorial/apb.html * doc/tutorial/apc.html * doc/tutorial/apd.html * doc/tutorial/ape.html * doc/tutorial/apf.html * doc/tutorial/apg.html * doc/tutorial/aph.html * doc/tutorial/ar01s02.html * doc/tutorial/ar01s03.html * doc/tutorial/ar01s04.html * doc/tutorial/ar01s05.html * doc/tutorial/ar01s06.html * doc/tutorial/ar01s07.html * doc/tutorial/ar01s08.html * doc/tutorial/index.html * doc/tutorial/ix01.html * doc/tutorial/xmltutorial.pdf * doc/tutorial/xmltutorial.xml update tutorial with XPath example
This commit is contained in:
MDT 2003 John Fleck
John Fleck
parent
597bc48bab
commit
63f3a47dbf
24
ChangeLog
24
ChangeLog
@ -1,3 +1,27 @@
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Thu Jul 24 15:46:02 MDT 2003 John Fleck <jfleck@inkstain.net>
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* doc/tutorial/apa.html
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* doc/tutorial/apb.html
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* doc/tutorial/apc.html
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* doc/tutorial/apd.html
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* doc/tutorial/ape.html
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* doc/tutorial/apf.html
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* doc/tutorial/apg.html
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* doc/tutorial/aph.html
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* doc/tutorial/ar01s02.html
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* doc/tutorial/ar01s03.html
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* doc/tutorial/ar01s04.html
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* doc/tutorial/ar01s05.html
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* doc/tutorial/ar01s06.html
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* doc/tutorial/ar01s07.html
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* doc/tutorial/ar01s08.html
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* doc/tutorial/index.html
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* doc/tutorial/ix01.html
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* doc/tutorial/xmltutorial.pdf
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* doc/tutorial/xmltutorial.xml
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update tutorial with XPath example
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Thu Jul 24 17:07:06 IST 2003 Daniel Veillard <daniel@veillard.com>
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* SAX.c parser.c: fixing a bug about a special case of namespace
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@ -1,9 +1,8 @@
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>A. Compilation</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s08.html" title="Encoding Conversion"><link rel="next" href="apb.html" title="B. Sample Document"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">A. Compilation</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s08.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apb.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="compilation"></a>A. Compilation</h2></div></div><div></div></div><p><a class="indexterm" name="id2814889"></a>
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>A. Compilation</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s09.html" title="Encoding Conversion"><link rel="next" href="apb.html" title="B. Sample Document"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">A. Compilation</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s09.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apb.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="compilation"></a>A. Compilation</h2></div></div><div></div></div><p><a class="indexterm" name="id2815236"></a>
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<span class="application">Libxml</span> includes a script,
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<span class="application">xml2-config</span>, that can be used to generate
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flags for compilation and linking of programs written with the
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library. For pre-processor and compiler flags, use <b class="command">xml2-config
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--cflags</b>. For library linking flags, use <b class="command">xml2-config
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--libs</b>. Other options are available using <b class="command">xml2-config
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--help</b>.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s08.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apb.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Encoding Conversion </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> B. Sample Document</td></tr></table></div></body></html>
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--help</b>.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s09.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apb.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Encoding Conversion </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> B. Sample Document</td></tr></table></div></body></html>
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@ -1,6 +1,5 @@
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>B. Sample Document</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apa.html" title="A. Compilation"><link rel="next" href="apc.html" title="C. Code for Keyword Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">B. Sample Document</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apa.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apc.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="sampledoc"></a>B. Sample Document</h2></div></div><div></div></div><pre class="programlisting">
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<?xml version="1.0"?>
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<?xml version="1.0"?>
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<story>
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<storyinfo>
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<author>John Fleck</author>
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@ -1,5 +1,4 @@
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>C. Code for Keyword Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apb.html" title="B. Sample Document"><link rel="next" href="apd.html" title="D. Code for Add Keyword Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">C. Code for Keyword Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apb.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apd.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="keywordappendix"></a>C. Code for Keyword Example</h2></div></div><div></div></div><p>
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>C. Code for Keyword Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apb.html" title="B. Sample Document"><link rel="next" href="apd.html" title="D. Code for XPath Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">C. Code for Keyword Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apb.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apd.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="keywordappendix"></a>C. Code for Keyword Example</h2></div></div><div></div></div><p>
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</p><pre class="programlisting">
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#include <stdio.h>
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#include <string.h>
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@ -13,9 +12,9 @@ parseStory (xmlDocPtr doc, xmlNodePtr cur) {
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xmlChar *key;
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cur = cur->xmlChildrenNode;
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while (cur != NULL) {
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if ((!xmlStrcmp(cur->name, (const xmlChar *)"keyword"))) {
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if ((!xmlStrcmp(cur->name, (const xmlChar *)"keyword"))) {
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key = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1);
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printf("keyword: %s\n", key);
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printf("keyword: %s\n", key);
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xmlFree(key);
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}
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cur = cur->next;
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@ -32,27 +31,27 @@ parseDoc(char *docname) {
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doc = xmlParseFile(docname);
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if (doc == NULL ) {
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fprintf(stderr,"Document not parsed successfully. \n");
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fprintf(stderr,"Document not parsed successfully. \n");
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return;
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}
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cur = xmlDocGetRootElement(doc);
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if (cur == NULL) {
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fprintf(stderr,"empty document\n");
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fprintf(stderr,"empty document\n");
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xmlFreeDoc(doc);
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return;
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}
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if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
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fprintf(stderr,"document of the wrong type, root node != story");
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if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
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fprintf(stderr,"document of the wrong type, root node != story");
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xmlFreeDoc(doc);
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return;
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}
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cur = cur->xmlChildrenNode;
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while (cur != NULL) {
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if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
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if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
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parseStory (doc, cur);
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}
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@ -69,7 +68,7 @@ main(int argc, char **argv) {
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char *docname;
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if (argc <= 1) {
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printf("Usage: %s docname\n", argv[0]);
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printf("Usage: %s docname\n", argv[0]);
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return(0);
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}
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@ -80,4 +79,4 @@ main(int argc, char **argv) {
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}
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</pre><p>
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</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apb.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apd.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">B. Sample Document </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> D. Code for Add Keyword Example</td></tr></table></div></body></html>
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</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apb.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apd.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">B. Sample Document </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> D. Code for XPath Example</td></tr></table></div></body></html>
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@ -1,79 +1,68 @@
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>D. Code for Add Keyword Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apc.html" title="C. Code for Keyword Example"><link rel="next" href="ape.html" title="E. Code for Add Attribute Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">D. Code for Add Keyword Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apc.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ape.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="addkeywordappendix"></a>D. Code for Add Keyword Example</h2></div></div><div></div></div><p>
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>D. Code for XPath Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apc.html" title="C. Code for Keyword Example"><link rel="next" href="ape.html" title="E. Code for Add Keyword Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">D. Code for XPath Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apc.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ape.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="xpathappendix"></a>D. Code for XPath Example</h2></div></div><div></div></div><p>
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</p><pre class="programlisting">
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <libxml/xmlmemory.h>
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#include <libxml/parser.h>
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void
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parseStory (xmlDocPtr doc, xmlNodePtr cur, char *keyword) {
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xmlNewTextChild (cur, NULL, "keyword", keyword);
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return;
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}
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#include <libxml/xpath.h>
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xmlDocPtr
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parseDoc(char *docname, char *keyword) {
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getdoc (char *docname) {
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xmlDocPtr doc;
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xmlNodePtr cur;
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doc = xmlParseFile(docname);
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if (doc == NULL ) {
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fprintf(stderr,"Document not parsed successfully. \n");
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return (NULL);
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fprintf(stderr,"Document not parsed successfully. \n");
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return NULL;
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}
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cur = xmlDocGetRootElement(doc);
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if (cur == NULL) {
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fprintf(stderr,"empty document\n");
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xmlFreeDoc(doc);
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return (NULL);
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}
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if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
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fprintf(stderr,"document of the wrong type, root node != story");
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xmlFreeDoc(doc);
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return (NULL);
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}
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cur = cur->xmlChildrenNode;
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while (cur != NULL) {
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if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
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parseStory (doc, cur, keyword);
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}
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cur = cur->next;
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}
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return(doc);
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return doc;
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}
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xmlXPathObjectPtr
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getnodeset (xmlDocPtr doc, xmlChar *xpath){
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xmlXPathContextPtr context;
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xmlXPathObjectPtr result;
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context = xmlXPathNewContext(doc);
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result = xmlXPathEvalExpression(xpath, context);
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if(xmlXPathNodeSetIsEmpty(result->nodesetval)){
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printf("No result\n");
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return NULL;
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}
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xmlXPathFreeContext(context);
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return result;
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}
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int
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main(int argc, char **argv) {
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char *docname;
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char *keyword;
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xmlDocPtr doc;
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|
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if (argc <= 2) {
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printf("Usage: %s docname, keyword\n", argv[0]);
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xmlChar *xpath = ("//keyword");
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xmlNodeSetPtr nodeset;
|
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xmlXPathObjectPtr result;
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int i;
|
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xmlChar *keyword;
|
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|
||||
if (argc <= 1) {
|
||||
printf("Usage: %s docname\n", argv[0]);
|
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return(0);
|
||||
}
|
||||
|
||||
docname = argv[1];
|
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keyword = argv[2];
|
||||
doc = parseDoc (docname, keyword);
|
||||
if (doc != NULL) {
|
||||
xmlSaveFormatFile (docname, doc, 0);
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xmlFreeDoc(doc);
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doc = getdoc(docname);
|
||||
result = getnodeset (doc, xpath);
|
||||
if (result) {
|
||||
nodeset = result->nodesetval;
|
||||
for (i=0; i < nodeset->nodeNr; i++) {
|
||||
keyword = xmlNodeListGetString(doc, nodeset->nodeTab[i]->xmlChildrenNode, 1);
|
||||
printf("keyword: %s\n", keyword);
|
||||
}
|
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}
|
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|
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xmlXPathFreeObject (result);
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xmlFree(keyword);
|
||||
xmlFreeDoc(doc);
|
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xmlCleanupParser();
|
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return (1);
|
||||
}
|
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|
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</pre><p>
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</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apc.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ape.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">C. Code for Keyword Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> E. Code for Add Attribute Example</td></tr></table></div></body></html>
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</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apc.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ape.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">C. Code for Keyword Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> E. Code for Add Keyword Example</td></tr></table></div></body></html>
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@ -1,5 +1,4 @@
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>E. Code for Add Attribute Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apd.html" title="D. Code for Add Keyword Example"><link rel="next" href="apf.html" title="F. Code for Retrieving Attribute Value Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">E. Code for Add Attribute Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apd.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apf.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="addattributeappendix"></a>E. Code for Add Attribute Example</h2></div></div><div></div></div><p>
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>E. Code for Add Keyword Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apd.html" title="D. Code for XPath Example"><link rel="next" href="apf.html" title="F. Code for Add Attribute Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">E. Code for Add Keyword Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apd.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apf.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="addkeywordappendix"></a>E. Code for Add Keyword Example</h2></div></div><div></div></div><p>
|
||||
</p><pre class="programlisting">
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
@ -7,38 +6,48 @@
|
||||
#include <libxml/xmlmemory.h>
|
||||
#include <libxml/parser.h>
|
||||
|
||||
void
|
||||
parseStory (xmlDocPtr doc, xmlNodePtr cur, char *keyword) {
|
||||
|
||||
xmlNewTextChild (cur, NULL, "keyword", keyword);
|
||||
return;
|
||||
}
|
||||
|
||||
xmlDocPtr
|
||||
parseDoc(char *docname, char *uri) {
|
||||
parseDoc(char *docname, char *keyword) {
|
||||
|
||||
xmlDocPtr doc;
|
||||
xmlNodePtr cur;
|
||||
xmlNodePtr newnode;
|
||||
xmlAttrPtr newattr;
|
||||
|
||||
doc = xmlParseFile(docname);
|
||||
|
||||
if (doc == NULL ) {
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
return (NULL);
|
||||
}
|
||||
|
||||
cur = xmlDocGetRootElement(doc);
|
||||
|
||||
if (cur == NULL) {
|
||||
fprintf(stderr,"empty document\n");
|
||||
fprintf(stderr,"empty document\n");
|
||||
xmlFreeDoc(doc);
|
||||
return (NULL);
|
||||
}
|
||||
|
||||
if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
xmlFreeDoc(doc);
|
||||
return (NULL);
|
||||
}
|
||||
|
||||
newnode = xmlNewTextChild (cur, NULL, "reference", NULL);
|
||||
newattr = xmlNewProp (newnode, "uri", uri);
|
||||
cur = cur->xmlChildrenNode;
|
||||
while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
|
||||
parseStory (doc, cur, keyword);
|
||||
}
|
||||
|
||||
cur = cur->next;
|
||||
}
|
||||
return(doc);
|
||||
}
|
||||
|
||||
@ -46,23 +55,24 @@ int
|
||||
main(int argc, char **argv) {
|
||||
|
||||
char *docname;
|
||||
char *uri;
|
||||
char *keyword;
|
||||
xmlDocPtr doc;
|
||||
|
||||
if (argc <= 2) {
|
||||
printf("Usage: %s docname, uri\n", argv[0]);
|
||||
printf("Usage: %s docname, keyword\n", argv[0]);
|
||||
return(0);
|
||||
}
|
||||
|
||||
docname = argv[1];
|
||||
uri = argv[2];
|
||||
doc = parseDoc (docname, uri);
|
||||
keyword = argv[2];
|
||||
doc = parseDoc (docname, keyword);
|
||||
if (doc != NULL) {
|
||||
xmlSaveFormatFile (docname, doc, 1);
|
||||
xmlSaveFormatFile (docname, doc, 0);
|
||||
xmlFreeDoc(doc);
|
||||
}
|
||||
|
||||
return (1);
|
||||
}
|
||||
|
||||
</pre><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apd.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apf.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">D. Code for Add Keyword Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> F. Code for Retrieving Attribute Value Example</td></tr></table></div></body></html>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apd.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apf.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">D. Code for XPath Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> F. Code for Add Attribute Example</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,5 +1,4 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>F. Code for Retrieving Attribute Value Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ape.html" title="E. Code for Add Attribute Example"><link rel="next" href="apg.html" title="G. Code for Encoding Conversion Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">F. Code for Retrieving Attribute Value Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ape.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apg.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="getattributeappendix"></a>F. Code for Retrieving Attribute Value Example</h2></div></div><div></div></div><p>
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>F. Code for Add Attribute Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ape.html" title="E. Code for Add Keyword Example"><link rel="next" href="apg.html" title="G. Code for Retrieving Attribute Value Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">F. Code for Add Attribute Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ape.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apg.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="addattributeappendix"></a>F. Code for Add Attribute Example</h2></div></div><div></div></div><p>
|
||||
</p><pre class="programlisting">
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
@ -7,70 +6,62 @@
|
||||
#include <libxml/xmlmemory.h>
|
||||
#include <libxml/parser.h>
|
||||
|
||||
void
|
||||
getReference (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
|
||||
xmlChar *uri;
|
||||
cur = cur->xmlChildrenNode;
|
||||
while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"reference"))) {
|
||||
uri = xmlGetProp(cur, "uri");
|
||||
printf("uri: %s\n", uri);
|
||||
xmlFree(uri);
|
||||
}
|
||||
cur = cur->next;
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
|
||||
void
|
||||
parseDoc(char *docname) {
|
||||
xmlDocPtr
|
||||
parseDoc(char *docname, char *uri) {
|
||||
|
||||
xmlDocPtr doc;
|
||||
xmlNodePtr cur;
|
||||
xmlNodePtr newnode;
|
||||
xmlAttrPtr newattr;
|
||||
|
||||
doc = xmlParseFile(docname);
|
||||
|
||||
if (doc == NULL ) {
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
return;
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
return (NULL);
|
||||
}
|
||||
|
||||
cur = xmlDocGetRootElement(doc);
|
||||
|
||||
if (cur == NULL) {
|
||||
fprintf(stderr,"empty document\n");
|
||||
fprintf(stderr,"empty document\n");
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
return (NULL);
|
||||
}
|
||||
|
||||
if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
return (NULL);
|
||||
}
|
||||
|
||||
getReference (doc, cur);
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
newnode = xmlNewTextChild (cur, NULL, "reference", NULL);
|
||||
newattr = xmlNewProp (newnode, "uri", uri);
|
||||
return(doc);
|
||||
}
|
||||
|
||||
int
|
||||
main(int argc, char **argv) {
|
||||
|
||||
char *docname;
|
||||
char *uri;
|
||||
xmlDocPtr doc;
|
||||
|
||||
if (argc <= 1) {
|
||||
printf("Usage: %s docname\n", argv[0]);
|
||||
if (argc <= 2) {
|
||||
printf("Usage: %s docname, uri\n", argv[0]);
|
||||
return(0);
|
||||
}
|
||||
|
||||
docname = argv[1];
|
||||
parseDoc (docname);
|
||||
|
||||
uri = argv[2];
|
||||
doc = parseDoc (docname, uri);
|
||||
if (doc != NULL) {
|
||||
xmlSaveFormatFile (docname, doc, 1);
|
||||
xmlFreeDoc(doc);
|
||||
}
|
||||
return (1);
|
||||
}
|
||||
|
||||
</pre><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ape.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apg.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">E. Code for Add Attribute Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> G. Code for Encoding Conversion Example</td></tr></table></div></body></html>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ape.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apg.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">E. Code for Add Keyword Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> G. Code for Retrieving Attribute Value Example</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,77 +1,75 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>G. Code for Encoding Conversion Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apf.html" title="F. Code for Retrieving Attribute Value Example"><link rel="next" href="aph.html" title="H. Acknowledgements"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">G. Code for Encoding Conversion Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apf.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="aph.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="convertappendix"></a>G. Code for Encoding Conversion Example</h2></div></div><div></div></div><p>
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>G. Code for Retrieving Attribute Value Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apf.html" title="F. Code for Add Attribute Example"><link rel="next" href="aph.html" title="H. Code for Encoding Conversion Example"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">G. Code for Retrieving Attribute Value Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apf.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="aph.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="getattributeappendix"></a>G. Code for Retrieving Attribute Value Example</h2></div></div><div></div></div><p>
|
||||
</p><pre class="programlisting">
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <stdlib.h>
|
||||
#include <libxml/xmlmemory.h>
|
||||
#include <libxml/parser.h>
|
||||
|
||||
void
|
||||
getReference (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
|
||||
unsigned char*
|
||||
convert (unsigned char *in, char *encoding)
|
||||
{
|
||||
unsigned char *out;
|
||||
int ret,size,out_size,temp;
|
||||
xmlCharEncodingHandlerPtr handler;
|
||||
xmlChar *uri;
|
||||
cur = cur->xmlChildrenNode;
|
||||
while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"reference"))) {
|
||||
uri = xmlGetProp(cur, "uri");
|
||||
printf("uri: %s\n", uri);
|
||||
xmlFree(uri);
|
||||
}
|
||||
cur = cur->next;
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
size = (int)strlen(in)+1;
|
||||
out_size = size*2-1;
|
||||
out = malloc((size_t)out_size);
|
||||
|
||||
if (out) {
|
||||
handler = xmlFindCharEncodingHandler(encoding);
|
||||
|
||||
if (!handler) {
|
||||
free(out);
|
||||
out = NULL;
|
||||
}
|
||||
}
|
||||
if (out) {
|
||||
temp=size-1;
|
||||
ret = handler->input(out, &out_size, in, &temp);
|
||||
if (ret || temp-size+1) {
|
||||
if (ret) {
|
||||
printf("conversion wasn't successful.\n");
|
||||
} else {
|
||||
printf("conversion wasn't successful. converted: %i octets.\n",temp);
|
||||
}
|
||||
free(out);
|
||||
out = NULL;
|
||||
} else {
|
||||
out = realloc(out,out_size+1);
|
||||
out[out_size]=0; /*null terminating out*/
|
||||
|
||||
}
|
||||
} else {
|
||||
printf("no mem\n");
|
||||
}
|
||||
return (out);
|
||||
}
|
||||
void
|
||||
parseDoc(char *docname) {
|
||||
|
||||
xmlDocPtr doc;
|
||||
xmlNodePtr cur;
|
||||
|
||||
doc = xmlParseFile(docname);
|
||||
|
||||
if (doc == NULL ) {
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
return;
|
||||
}
|
||||
|
||||
cur = xmlDocGetRootElement(doc);
|
||||
|
||||
if (cur == NULL) {
|
||||
fprintf(stderr,"empty document\n");
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
}
|
||||
|
||||
if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
}
|
||||
|
||||
getReference (doc, cur);
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
}
|
||||
|
||||
int
|
||||
main(int argc, char **argv) {
|
||||
|
||||
unsigned char *content, *out;
|
||||
xmlDocPtr doc;
|
||||
xmlNodePtr rootnode;
|
||||
char *encoding = "ISO-8859-1";
|
||||
|
||||
|
||||
char *docname;
|
||||
|
||||
if (argc <= 1) {
|
||||
printf("Usage: %s content\n", argv[0]);
|
||||
printf("Usage: %s docname\n", argv[0]);
|
||||
return(0);
|
||||
}
|
||||
|
||||
content = argv[1];
|
||||
|
||||
out = convert(content, encoding);
|
||||
|
||||
doc = xmlNewDoc ("1.0");
|
||||
rootnode = xmlNewDocNode(doc, NULL, (const xmlChar*)"root", out);
|
||||
xmlDocSetRootElement(doc, rootnode);
|
||||
|
||||
xmlSaveFormatFileEnc("-", doc, encoding, 1);
|
||||
docname = argv[1];
|
||||
parseDoc (docname);
|
||||
|
||||
return (1);
|
||||
}
|
||||
|
||||
</pre><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apf.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="aph.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">F. Code for Retrieving Attribute Value Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> H. Acknowledgements</td></tr></table></div></body></html>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apf.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="aph.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">F. Code for Add Attribute Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> H. Code for Encoding Conversion Example</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,5 +1,76 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>H. Acknowledgements</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apg.html" title="G. Code for Encoding Conversion Example"><link rel="next" href="ix01.html" title="Index"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">H. Acknowledgements</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apg.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ix01.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2815353"></a>H. Acknowledgements</h2></div></div><div></div></div><p>A number of people have generously offered feedback, code and
|
||||
suggested improvements to this tutorial. In no particular order:
|
||||
<span class="simplelist">Daniel Veillard, Marcus Labib Iskander, Christopher R. Harris, Igor Zlatkovic, Niraj Tolia</span>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apg.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ix01.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">G. Code for Encoding Conversion Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Index</td></tr></table></div></body></html>
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>H. Code for Encoding Conversion Example</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="apg.html" title="G. Code for Retrieving Attribute Value Example"><link rel="next" href="api.html" title="I. Acknowledgements"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">H. Code for Encoding Conversion Example</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="apg.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="api.html">Next</a></td></tr></table><hr></div><div class="appendix" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="convertappendix"></a>H. Code for Encoding Conversion Example</h2></div></div><div></div></div><p>
|
||||
</p><pre class="programlisting">
|
||||
#include <string.h>
|
||||
#include <libxml/parser.h>
|
||||
|
||||
|
||||
unsigned char*
|
||||
convert (unsigned char *in, char *encoding)
|
||||
{
|
||||
unsigned char *out;
|
||||
int ret,size,out_size,temp;
|
||||
xmlCharEncodingHandlerPtr handler;
|
||||
|
||||
size = (int)strlen(in)+1;
|
||||
out_size = size*2-1;
|
||||
out = malloc((size_t)out_size);
|
||||
|
||||
if (out) {
|
||||
handler = xmlFindCharEncodingHandler(encoding);
|
||||
|
||||
if (!handler) {
|
||||
free(out);
|
||||
out = NULL;
|
||||
}
|
||||
}
|
||||
if (out) {
|
||||
temp=size-1;
|
||||
ret = handler->input(out, &out_size, in, &temp);
|
||||
if (ret || temp-size+1) {
|
||||
if (ret) {
|
||||
printf("conversion wasn't successful.\n");
|
||||
} else {
|
||||
printf("conversion wasn't successful. converted: %i octets.\n",temp);
|
||||
}
|
||||
free(out);
|
||||
out = NULL;
|
||||
} else {
|
||||
out = realloc(out,out_size+1);
|
||||
out[out_size]=0; /*null terminating out*/
|
||||
|
||||
}
|
||||
} else {
|
||||
printf("no mem\n");
|
||||
}
|
||||
return (out);
|
||||
}
|
||||
|
||||
|
||||
int
|
||||
main(int argc, char **argv) {
|
||||
|
||||
unsigned char *content, *out;
|
||||
xmlDocPtr doc;
|
||||
xmlNodePtr rootnode;
|
||||
char *encoding = "ISO-8859-1";
|
||||
|
||||
|
||||
if (argc <= 1) {
|
||||
printf("Usage: %s content\n", argv[0]);
|
||||
return(0);
|
||||
}
|
||||
|
||||
content = argv[1];
|
||||
|
||||
out = convert(content, encoding);
|
||||
|
||||
doc = xmlNewDoc ("1.0");
|
||||
rootnode = xmlNewDocNode(doc, NULL, (const xmlChar*)"root", out);
|
||||
xmlDocSetRootElement(doc, rootnode);
|
||||
|
||||
xmlSaveFormatFileEnc("-", doc, encoding, 1);
|
||||
return (1);
|
||||
}
|
||||
|
||||
</pre><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="apg.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="api.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">G. Code for Retrieving Attribute Value Example </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> I. Acknowledgements</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,14 +1,13 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Data Types</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="index.html" title="Libxml Tutorial"><link rel="next" href="ar01s03.html" title="Parsing the file"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Data Types</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="index.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s03.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialdatatypes"></a>Data Types</h2></div></div><div></div></div><p><span class="application">Libxml</span> declares a number of data types we
|
||||
will encounter repeatedly, hiding the messy stuff so you do not have to deal
|
||||
with it unless you have some specific need.</p><p>
|
||||
</p><div class="variablelist"><dl><dt><span class="term"><a class="indexterm" name="id2816027"></a>
|
||||
</p><div class="variablelist"><dl><dt><span class="term"><a class="indexterm" name="id2815889"></a>
|
||||
<a href="http://xmlsoft.org/html/libxml-tree.html#XMLCHAR" target="_top">xmlChar</a></span></dt><dd><p>A basic replacement for char, a byte in a UTF-8 encoded
|
||||
string. If your data uses another encoding, it must be converted to
|
||||
UTF-8 for use with <span class="application">libxml's</span>
|
||||
functions. More information on encoding is available on the <a href="http://www.xmlsoft.org/encoding.html" target="_top"><span class="application">libxml</span> encoding support web page</a>.</p></dd><dt><span class="term"><a class="indexterm" name="id2816083"></a>
|
||||
functions. More information on encoding is available on the <a href="http://www.xmlsoft.org/encoding.html" target="_top"><span class="application">libxml</span> encoding support web page</a>.</p></dd><dt><span class="term"><a class="indexterm" name="id2815945"></a>
|
||||
<a href="http://xmlsoft.org/html/libxml-tree.html#XMLDOC" target="_top">xmlDoc</a></span></dt><dd><p>A structure containing the tree created by a parsed doc. <a href="http://xmlsoft.org/html/libxml-tree.html#XMLDOCPTR" target="_top">xmlDocPtr</a>
|
||||
is a pointer to the structure.</p></dd><dt><span class="term"><a class="indexterm" name="id2816125"></a>
|
||||
is a pointer to the structure.</p></dd><dt><span class="term"><a class="indexterm" name="id2815986"></a>
|
||||
<a href="http://xmlsoft.org/html/libxml-tree.html#XMLNODEPTR" target="_top">xmlNodePtr</a>
|
||||
and <a href="http://xmlsoft.org/html/libxml-tree.html#XMLNODE" target="_top">xmlNode</a></span></dt><dd><p>A structure containing a single node. <a href="http://xmlsoft.org/html/libxml-tree.html#XMLNODEPTR" target="_top">xmlNodePtr</a>
|
||||
is a pointer to the structure, and is used in traversing the document tree.</p></dd></dl></div><p>
|
||||
|
||||
@ -1,4 +1,3 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Parsing the file</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s02.html" title="Data Types"><link rel="next" href="ar01s04.html" title="Retrieving Element Content"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Parsing the file</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s02.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s04.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialparsing"></a>Parsing the file</h2></div></div><div></div></div><p><a class="indexterm" name="fileparsing"></a>
|
||||
Parsing the file requires only the name of the file and a single
|
||||
function call, plus error checking. Full code: <a href="apc.html" title="C. Code for Keyword Example">Appendix C, <i>Code for Keyword Example</i></a></p><p>
|
||||
@ -9,20 +8,20 @@ Parsing the file requires only the name of the file and a single
|
||||
<a name="parsefile"></a><img src="images/callouts/3.png" alt="3" border="0"> doc = xmlParseFile(docname);
|
||||
|
||||
<a name="checkparseerror"></a><img src="images/callouts/4.png" alt="4" border="0"> if (doc == NULL ) {
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
fprintf(stderr,"Document not parsed successfully. \n");
|
||||
return;
|
||||
}
|
||||
|
||||
<a name="getrootelement"></a><img src="images/callouts/5.png" alt="5" border="0"> cur = xmlDocGetRootElement(doc);
|
||||
|
||||
<a name="checkemptyerror"></a><img src="images/callouts/6.png" alt="6" border="0"> if (cur == NULL) {
|
||||
fprintf(stderr,"empty document\n");
|
||||
fprintf(stderr,"empty document\n");
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
}
|
||||
|
||||
<a name="checkroottype"></a><img src="images/callouts/7.png" alt="7" border="0"> if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
<a name="checkroottype"></a><img src="images/callouts/7.png" alt="7" border="0"> if (xmlStrcmp(cur->name, (const xmlChar *) "story")) {
|
||||
fprintf(stderr,"document of the wrong type, root node != story");
|
||||
xmlFreeDoc(doc);
|
||||
return;
|
||||
}
|
||||
@ -32,7 +31,7 @@ Parsing the file requires only the name of the file and a single
|
||||
interact with individual nodes).</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#checkparseerror"><img src="images/callouts/4.png" alt="4" border="0"></a> </td><td valign="top" align="left"><p>Check to see that the document was successfully parsed. If it
|
||||
was not, <span class="application">libxml</span> will at this point
|
||||
register an error and stop.
|
||||
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p><a class="indexterm" name="id2867695"></a>
|
||||
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p><a class="indexterm" name="id2816318"></a>
|
||||
One common example of an error at this point is improper
|
||||
handling of encoding. The <span class="acronym">XML</span> standard requires
|
||||
documents stored with an encoding other than UTF-8 or UTF-16 to
|
||||
@ -42,7 +41,7 @@ One common example of an error at this point is improper
|
||||
you. More information on <span class="acronym">XML's</span> encoding
|
||||
requirements is contained in the <a href="http://www.w3.org/TR/REC-xml#charencoding" target="_top">standard</a>.</p></td></tr></table></div><p>
|
||||
</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#getrootelement"><img src="images/callouts/5.png" alt="5" border="0"></a> </td><td valign="top" align="left"><p>Retrieve the document's root element.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#checkemptyerror"><img src="images/callouts/6.png" alt="6" border="0"></a> </td><td valign="top" align="left"><p>Check to make sure the document actually contains something.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#checkroottype"><img src="images/callouts/7.png" alt="7" border="0"></a> </td><td valign="top" align="left"><p>In our case, we need to make sure the document is the right
|
||||
type. "story" is the root type of the documents used in this
|
||||
type. "story" is the root type of the documents used in this
|
||||
tutorial.</p></td></tr></table></div><p>
|
||||
<a class="indexterm" name="id2867789"></a>
|
||||
<a class="indexterm" name="id2816412"></a>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s02.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Data Types </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Retrieving Element Content</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,15 +1,14 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Retrieving Element Content</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s03.html" title="Parsing the file"><link rel="next" href="ar01s05.html" title="Writing element content"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Retrieving Element Content</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s03.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s05.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialgettext"></a>Retrieving Element Content</h2></div></div><div></div></div><p><a class="indexterm" name="id2867816"></a>
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Retrieving Element Content</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s03.html" title="Parsing the file"><link rel="next" href="ar01s05.html" title="Using XPath to Retrieve Element Content"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Retrieving Element Content</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s03.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s05.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialgettext"></a>Retrieving Element Content</h2></div></div><div></div></div><p><a class="indexterm" name="id2816439"></a>
|
||||
Retrieving the content of an element involves traversing the document
|
||||
tree until you find what you are looking for. In this case, we are looking
|
||||
for an element called "keyword" contained within element called "story". The
|
||||
for an element called "keyword" contained within element called "story". The
|
||||
process to find the node we are interested in involves tediously walking the
|
||||
tree. We assume you already have an xmlDocPtr called <tt class="varname">doc</tt>
|
||||
and an xmlNodPtr called <tt class="varname">cur</tt>.</p><p>
|
||||
</p><pre class="programlisting">
|
||||
<a name="getchildnode"></a><img src="images/callouts/1.png" alt="1" border="0">cur = cur->xmlChildrenNode;
|
||||
<a name="huntstoryinfo"></a><img src="images/callouts/2.png" alt="2" border="0">while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"storyinfo"))){
|
||||
parseStory (doc, cur);
|
||||
}
|
||||
|
||||
@ -19,9 +18,9 @@ Retrieving the content of an element involves traversing the document
|
||||
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#getchildnode"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>Get the first child node of <tt class="varname">cur</tt>. At this
|
||||
point, <tt class="varname">cur</tt> points at the document root, which is
|
||||
the element "story".</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#huntstoryinfo"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>This loop iterates through the elements that are children of
|
||||
"story", looking for one called "storyinfo". That
|
||||
is the element that will contain the "keywords" we are
|
||||
the element "story".</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#huntstoryinfo"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>This loop iterates through the elements that are children of
|
||||
"story", looking for one called "storyinfo". That
|
||||
is the element that will contain the "keywords" we are
|
||||
looking for. It uses the <span class="application">libxml</span> string
|
||||
comparison
|
||||
function, <tt class="function"><a href="http://xmlsoft.org/html/libxml-parser.html#XMLSTRCMP" target="_top">xmlStrcmp</a></tt>. If there is a match, it calls the function <tt class="function">parseStory</tt>.</p></td></tr></table></div><p>
|
||||
@ -33,9 +32,9 @@ parseStory (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
xmlChar *key;
|
||||
<a name="anothergetchild"></a><img src="images/callouts/1.png" alt="1" border="0"> cur = cur->xmlChildrenNode;
|
||||
<a name="findkeyword"></a><img src="images/callouts/2.png" alt="2" border="0"> while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"keyword"))) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"keyword"))) {
|
||||
<a name="foundkeyword"></a><img src="images/callouts/3.png" alt="3" border="0"> key = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1);
|
||||
printf("keyword: %s\n", key);
|
||||
printf("keyword: %s\n", key);
|
||||
xmlFree(key);
|
||||
}
|
||||
cur = cur->next;
|
||||
@ -45,11 +44,11 @@ parseStory (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
</pre><p>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#anothergetchild"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>Again we get the first child node.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#findkeyword"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>Like the loop above, we then iterate through the nodes, looking
|
||||
for one that matches the element we're interested in, in this case
|
||||
"keyword".</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#foundkeyword"><img src="images/callouts/3.png" alt="3" border="0"></a> </td><td valign="top" align="left"><p>When we find the "keyword" element, we need to print
|
||||
"keyword".</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#foundkeyword"><img src="images/callouts/3.png" alt="3" border="0"></a> </td><td valign="top" align="left"><p>When we find the "keyword" element, we need to print
|
||||
its contents. Remember that in <span class="acronym">XML</span>, the text
|
||||
contained within an element is a child node of that element, so we
|
||||
turn to <tt class="varname">cur->xmlChildrenNode</tt>. To retrieve it, we
|
||||
use the function <tt class="function"><a href="http://xmlsoft.org/html/libxml-tree.html#XMLNODELISTGETSTRING" target="_top">xmlNodeListGetString</a></tt>, which also takes the <tt class="varname">doc</tt> pointer as an argument. In this case, we just print it out.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p>Because <tt class="function">xmlNodeListGetString</tt> allocates
|
||||
memory for the string it returns, you must use
|
||||
<tt class="function">xmlFree</tt> to free it.</p></td></tr></table></div></td></tr></table></div><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s03.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s05.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Parsing the file </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Writing element content</td></tr></table></div></body></html>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s03.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s05.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Parsing the file </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Using XPath to Retrieve Element Content</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,36 +1,55 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Writing element content</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s04.html" title="Retrieving Element Content"><link rel="next" href="ar01s06.html" title="Writing Attribute"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Writing element content</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s04.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s06.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialwritingcontent"></a>Writing element content</h2></div></div><div></div></div><p><a class="indexterm" name="id2868124"></a>
|
||||
Writing element content uses many of the same steps we used above
|
||||
— parsing the document and walking the tree. We parse the document,
|
||||
then traverse the tree to find the place we want to insert our element. For
|
||||
this example, we want to again find the "storyinfo" element and
|
||||
this time insert a keyword. Then we'll write the file to disk. Full code:
|
||||
<a href="apd.html" title="D. Code for Add Keyword Example">Appendix D, <i>Code for Add Keyword Example</i></a></p><p>
|
||||
The main difference in this example is in
|
||||
<tt class="function">parseStory</tt>:
|
||||
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Using XPath to Retrieve Element Content</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s04.html" title="Retrieving Element Content"><link rel="next" href="ar01s06.html" title="Writing element content"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Using XPath to Retrieve Element Content</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s04.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s06.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialxpath"></a>Using XPath to Retrieve Element Content</h2></div></div><div></div></div><p>In addition to walking the document tree to find an element,
|
||||
<span class="application">Libxml2</span> includes support for
|
||||
use of <span class="application">XPath</span> expressions to retrieve sets of
|
||||
nodes that match a specified criteria. Full documentation of the
|
||||
<span class="application">XPath</span> <span class="acronym">API</span> is <a href="http://xmlsoft.org/html/libxml-xpath.html" target="_top">here</a>.
|
||||
</p><p><span class="application">XPath</span> allows searching through a document
|
||||
for nodes that match specified criteria. In the example below we search
|
||||
through a document for the contents of all <tt class="varname">keyword</tt>
|
||||
elements.
|
||||
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p>A full discussion of <span class="application">XPath</span> is beyond
|
||||
the scope of this document. For details on its use, see the <a href="http://www.w3.org/TR/xpath" target="_top">XPath specification</a>.</p></td></tr></table></div><p>
|
||||
Full code for this example is at <a href="apd.html" title="D. Code for XPath Example">Appendix D, <i>Code for XPath Example</i></a>.
|
||||
</p><p>Using <span class="application">XPath</span> requires setting up an
|
||||
xmlXPathContext and then supplying the <span class="application">XPath</span>
|
||||
expression and the context to the
|
||||
<tt class="function">xmlXPathEvalExpression</tt> function. The function returns
|
||||
an xmlXPathObjectPtr, which includes the set of nodes satisfying the
|
||||
<span class="application">XPath</span> expression.</p><p>
|
||||
</p><pre class="programlisting">
|
||||
void
|
||||
parseStory (xmlDocPtr doc, xmlNodePtr cur, char *keyword) {
|
||||
xmlXPathObjectPtr
|
||||
getnodeset (xmlDocPtr doc, xmlChar *xpath){
|
||||
|
||||
<a name="cocontext"></a><img src="images/callouts/1.png" alt="1" border="0">xmlXPathContextPtr context;
|
||||
xmlXPathObjectPtr result;
|
||||
|
||||
<a name="addkeyword"></a><img src="images/callouts/1.png" alt="1" border="0"> xmlNewTextChild (cur, NULL, "keyword", keyword);
|
||||
return;
|
||||
}
|
||||
<a name="cocreatecontext"></a><img src="images/callouts/2.png" alt="2" border="0">context = xmlXPathNewContext(doc);
|
||||
<a name="corunxpath"></a><img src="images/callouts/3.png" alt="3" border="0">result = xmlXPathEvalExpression(xpath, context);
|
||||
<a name="cocheckxpathresult"></a><img src="images/callouts/4.png" alt="4" border="0">if(xmlXPathNodeSetIsEmpty(result->nodesetval)){
|
||||
printf("No result\n");
|
||||
return NULL;
|
||||
}
|
||||
xmlXPathFreeContext(context);
|
||||
return result;
|
||||
</pre><p>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#addkeyword"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>The <tt class="function"><a href="http://xmlsoft.org/html/libxml-tree.html#XMLNEWTEXTCHILD" target="_top">xmlNewTextChild</a></tt>
|
||||
function adds a new child element at the
|
||||
current node pointer's location in the
|
||||
tree, specified by <tt class="varname">cur</tt>.</p></td></tr></table></div><p>
|
||||
</p><p>
|
||||
<a class="indexterm" name="id2814166"></a>
|
||||
Once the node has been added, we would like to write the document to
|
||||
file. Is you want the element to have a namespace, you can add it here as
|
||||
well. In our case, the namespace is NULL.
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#cocontext"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>First we declare our variables.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#cocreatecontext"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>Initialize the <tt class="varname">context</tt> variable.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#corunxpath"><img src="images/callouts/3.png" alt="3" border="0"></a> </td><td valign="top" align="left"><p>Apply the <span class="application">XPath</span> expression.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#cocheckxpathresult"><img src="images/callouts/4.png" alt="4" border="0"></a> </td><td valign="top" align="left"><p>Check the result.</p></td></tr></table></div><p>
|
||||
</p><p>The xmlPathObjectPtr returned by the function contains a set of nodes
|
||||
and other information needed to iterate through the set and act on the
|
||||
results. For this example, our functions returns the
|
||||
<tt class="varname">xmlXPathObjectPtr</tt>. We use it to print the contents of
|
||||
<tt class="varname">keyword</tt> nodes in our document. The node set object
|
||||
includes the number of elements in the set (<tt class="varname">nodeNr</tt>) and
|
||||
an array of nodes (<tt class="varname">nodeTab</tt>):
|
||||
</p><pre class="programlisting">
|
||||
xmlSaveFormatFile (docname, doc, 1);
|
||||
<a name="conodesetcounter"></a><img src="images/callouts/1.png" alt="1" border="0">for (i=0; i < nodeset->nodeNr; i++) {
|
||||
<a name="coprintkeywords"></a><img src="images/callouts/2.png" alt="2" border="0">keyword = xmlNodeListGetString(doc, nodeset->nodeTab[i]->xmlChildrenNode, 1);
|
||||
printf("keyword: %s\n", keyword);
|
||||
}
|
||||
</pre><p>
|
||||
The first parameter is the name of the file to be written. You'll notice
|
||||
it is the same as the file we just read. In this case, we just write over
|
||||
the old file. The second parameter is a pointer to the xmlDoc
|
||||
structure. Setting the third parameter equal to one ensures indenting on output.
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s04.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s06.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Retrieving Element Content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Writing Attribute</td></tr></table></div></body></html>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#conodesetcounter"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>The value of <tt class="varname">nodeset->Nr</tt> holds the number of
|
||||
elements in the node set. Here we use it to iterate through the array.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#coprintkeywords"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>Here we print the contents of each of the nodes returned.
|
||||
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p>Note that we are printing the child node of the node that is
|
||||
returned, because the contents of the <tt class="varname">keyword</tt>
|
||||
element are a child text node.</p></td></tr></table></div><p>
|
||||
</p></td></tr></table></div><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s04.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s06.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Retrieving Element Content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Writing element content</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,31 +1,35 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Writing Attribute</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s05.html" title="Writing element content"><link rel="next" href="ar01s07.html" title="Retrieving Attributes"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Writing Attribute</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s05.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s07.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialwritingattribute"></a>Writing Attribute</h2></div></div><div></div></div><p><a class="indexterm" name="id2814216"></a>
|
||||
Writing an attribute is similar to writing text to a new element. In
|
||||
this case, we'll add a reference <span class="acronym">URI</span> to our
|
||||
document. Full code:<a href="ape.html" title="E. Code for Add Attribute Example">Appendix E, <i>Code for Add Attribute Example</i></a>.</p><p>
|
||||
A <tt class="sgmltag-element">reference</tt> is a child of the <tt class="sgmltag-element">story</tt>
|
||||
element, so finding the place to put our new element and attribute is
|
||||
simple. As soon as we do the error-checking test in our
|
||||
<tt class="function">parseDoc</tt>, we are in the right spot to add our
|
||||
element. But before we do that, we need to make a declaration using a
|
||||
data type we have not seen yet:
|
||||
</p><pre class="programlisting">
|
||||
xmlAttrPtr newattr;
|
||||
</pre><p>
|
||||
We also need an extra xmlNodePtr:
|
||||
</p><pre class="programlisting">
|
||||
xmlNodePtr newnode;
|
||||
</pre><p>
|
||||
</p><p>
|
||||
The rest of <tt class="function">parseDoc</tt> is the same as before until we
|
||||
check to see if our root element is <tt class="sgmltag-element">story</tt>. If it is,
|
||||
then we know we are at the right spot to add our element:
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Writing element content</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s05.html" title="Using XPath to Retrieve Element Content"><link rel="next" href="ar01s07.html" title="Writing Attribute"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Writing element content</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s05.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s07.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialwritingcontent"></a>Writing element content</h2></div></div><div></div></div><p><a class="indexterm" name="id2814412"></a>
|
||||
Writing element content uses many of the same steps we used above
|
||||
— parsing the document and walking the tree. We parse the document,
|
||||
then traverse the tree to find the place we want to insert our element. For
|
||||
this example, we want to again find the "storyinfo" element and
|
||||
this time insert a keyword. Then we'll write the file to disk. Full code:
|
||||
<a href="ape.html" title="E. Code for Add Keyword Example">Appendix E, <i>Code for Add Keyword Example</i></a></p><p>
|
||||
The main difference in this example is in
|
||||
<tt class="function">parseStory</tt>:
|
||||
|
||||
</p><pre class="programlisting">
|
||||
<a name="addreferencenode"></a><img src="images/callouts/1.png" alt="1" border="0"> newnode = xmlNewTextChild (cur, NULL, "reference", NULL);
|
||||
<a name="addattributenode"></a><img src="images/callouts/2.png" alt="2" border="0"> newattr = xmlNewProp (newnode, "uri", uri);
|
||||
void
|
||||
parseStory (xmlDocPtr doc, xmlNodePtr cur, char *keyword) {
|
||||
|
||||
<a name="addkeyword"></a><img src="images/callouts/1.png" alt="1" border="0"> xmlNewTextChild (cur, NULL, "keyword", keyword);
|
||||
return;
|
||||
}
|
||||
</pre><p>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#addreferencenode"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>First we add a new node at the location of the current node
|
||||
pointer, <tt class="varname">cur.</tt> using the <a href="http://xmlsoft.org/html/libxml-tree.html#XMLNEWTEXTCHILD" target="_top">xmlNewTextChild</a> function.</p></td></tr></table></div><p>
|
||||
</p><p>Once the node is added, the file is written to disk just as in the
|
||||
previous example in which we added an element with text content.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s05.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s07.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Writing element content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Retrieving Attributes</td></tr></table></div></body></html>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#addkeyword"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>The <tt class="function"><a href="http://xmlsoft.org/html/libxml-tree.html#XMLNEWTEXTCHILD" target="_top">xmlNewTextChild</a></tt>
|
||||
function adds a new child element at the
|
||||
current node pointer's location in the
|
||||
tree, specified by <tt class="varname">cur</tt>.</p></td></tr></table></div><p>
|
||||
</p><p>
|
||||
<a class="indexterm" name="id2814512"></a>
|
||||
Once the node has been added, we would like to write the document to
|
||||
file. Is you want the element to have a namespace, you can add it here as
|
||||
well. In our case, the namespace is NULL.
|
||||
</p><pre class="programlisting">
|
||||
xmlSaveFormatFile (docname, doc, 1);
|
||||
</pre><p>
|
||||
The first parameter is the name of the file to be written. You'll notice
|
||||
it is the same as the file we just read. In this case, we just write over
|
||||
the old file. The second parameter is a pointer to the xmlDoc
|
||||
structure. Setting the third parameter equal to one ensures indenting on output.
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s05.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s07.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Using XPath to Retrieve Element Content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Writing Attribute</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,39 +1,30 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Retrieving Attributes</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s06.html" title="Writing Attribute"><link rel="next" href="ar01s08.html" title="Encoding Conversion"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Retrieving Attributes</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s06.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s08.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialattribute"></a>Retrieving Attributes</h2></div></div><div></div></div><p><a class="indexterm" name="id2814383"></a>
|
||||
Retrieving the value of an attribute is similar to the previous
|
||||
example in which we retrieved a node's text contents. In this case we'll
|
||||
extract the value of the <span class="acronym">URI</span> we added in the previous
|
||||
section. Full code: <a href="apf.html" title="F. Code for Retrieving Attribute Value Example">Appendix F, <i>Code for Retrieving Attribute Value Example</i></a>.</p><p>
|
||||
The initial steps for this example are similar to the previous ones: parse
|
||||
the doc, find the element you are interested in, then enter a function to
|
||||
carry out the specific task required. In this case, we call
|
||||
<tt class="function">getReference</tt>:
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Writing Attribute</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s06.html" title="Writing element content"><link rel="next" href="ar01s08.html" title="Retrieving Attributes"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Writing Attribute</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s06.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s08.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialwritingattribute"></a>Writing Attribute</h2></div></div><div></div></div><p><a class="indexterm" name="id2814563"></a>
|
||||
Writing an attribute is similar to writing text to a new element. In
|
||||
this case, we'll add a reference <span class="acronym">URI</span> to our
|
||||
document. Full code:<a href="apf.html" title="F. Code for Add Attribute Example">Appendix F, <i>Code for Add Attribute Example</i></a>.</p><p>
|
||||
A <tt class="sgmltag-element">reference</tt> is a child of the <tt class="sgmltag-element">story</tt>
|
||||
element, so finding the place to put our new element and attribute is
|
||||
simple. As soon as we do the error-checking test in our
|
||||
<tt class="function">parseDoc</tt>, we are in the right spot to add our
|
||||
element. But before we do that, we need to make a declaration using a
|
||||
data type we have not seen yet:
|
||||
</p><pre class="programlisting">
|
||||
void
|
||||
getReference (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
|
||||
xmlChar *uri;
|
||||
cur = cur->xmlChildrenNode;
|
||||
while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"reference"))) {
|
||||
<a name="getattributevalue"></a><img src="images/callouts/1.png" alt="1" border="0"> uri = xmlGetProp(cur, "uri");
|
||||
printf("uri: %s\n", uri);
|
||||
xmlFree(uri);
|
||||
}
|
||||
cur = cur->next;
|
||||
}
|
||||
return;
|
||||
}
|
||||
xmlAttrPtr newattr;
|
||||
</pre><p>
|
||||
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#getattributevalue"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>
|
||||
The key function is <tt class="function"><a href="http://xmlsoft.org/html/libxml-tree.html#XMLGETPROP" target="_top">xmlGetProp</a></tt>, which returns an
|
||||
<tt class="varname">xmlChar</tt> containing the attribute's value. In this case,
|
||||
we just print it out.
|
||||
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p>
|
||||
If you are using a <span class="acronym">DTD</span> that declares a fixed or
|
||||
default value for the attribute, this function will retrieve it.
|
||||
</p></td></tr></table></div><p>
|
||||
</p></td></tr></table></div><p>
|
||||
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s06.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s08.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Writing Attribute </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Encoding Conversion</td></tr></table></div></body></html>
|
||||
We also need an extra xmlNodePtr:
|
||||
</p><pre class="programlisting">
|
||||
xmlNodePtr newnode;
|
||||
</pre><p>
|
||||
</p><p>
|
||||
The rest of <tt class="function">parseDoc</tt> is the same as before until we
|
||||
check to see if our root element is <tt class="sgmltag-element">story</tt>. If it is,
|
||||
then we know we are at the right spot to add our element:
|
||||
|
||||
</p><pre class="programlisting">
|
||||
<a name="addreferencenode"></a><img src="images/callouts/1.png" alt="1" border="0"> newnode = xmlNewTextChild (cur, NULL, "reference", NULL);
|
||||
<a name="addattributenode"></a><img src="images/callouts/2.png" alt="2" border="0"> newattr = xmlNewProp (newnode, "uri", uri);
|
||||
</pre><p>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#addreferencenode"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>First we add a new node at the location of the current node
|
||||
pointer, <tt class="varname">cur.</tt> using the <a href="http://xmlsoft.org/html/libxml-tree.html#XMLNEWTEXTCHILD" target="_top">xmlNewTextChild</a> function.</p></td></tr></table></div><p>
|
||||
</p><p>Once the node is added, the file is written to disk just as in the
|
||||
previous example in which we added an element with text content.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s06.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s08.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Writing element content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Retrieving Attributes</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,64 +1,38 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Encoding Conversion</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s07.html" title="Retrieving Attributes"><link rel="next" href="apa.html" title="A. Compilation"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Encoding Conversion</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s07.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="apa.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialconvert"></a>Encoding Conversion</h2></div></div><div></div></div><p><a class="indexterm" name="id2814514"></a>
|
||||
Data encoding compatibility problems are one of the most common
|
||||
difficulties encountered by programmers new to <span class="acronym">XML</span> in
|
||||
general and <span class="application">libxml</span> in particular. Thinking
|
||||
through the design of your application in light of this issue will help
|
||||
avoid difficulties later. Internally, <span class="application">libxml</span>
|
||||
stores and manipulates data in the UTF-8 format. Data used by your program
|
||||
in other formats, such as the commonly used ISO-8859-1 encoding, must be
|
||||
converted to UTF-8 before passing it to <span class="application">libxml</span>
|
||||
functions. If you want your program's output in an encoding other than
|
||||
UTF-8, you also must convert it.</p><p><span class="application">Libxml</span> uses
|
||||
<span class="application">iconv</span> if it is available to convert
|
||||
data. Without <span class="application">iconv</span>, only UTF-8, UTF-16 and
|
||||
ISO-8859-1 can be used as external formats. With
|
||||
<span class="application">iconv</span>, any format can be used provided
|
||||
<span class="application">iconv</span> is able to convert it to and from
|
||||
UTF-8. Currently <span class="application">iconv</span> supports about 150
|
||||
different character formats with ability to convert from any to any. While
|
||||
the actual number of supported formats varies between implementations, every
|
||||
<span class="application">iconv</span> implementation is almost guaranteed to
|
||||
support every format anyone has ever heard of.</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Warning"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="images/warning.png"></td><th align="left">Warning</th></tr><tr><td colspan="2" align="left" valign="top"><p>A common mistake is to use different formats for the internal data
|
||||
in different parts of one's code. The most common case is an application
|
||||
that assumes ISO-8859-1 to be the internal data format, combined with
|
||||
<span class="application">libxml</span>, which assumes UTF-8 to be the
|
||||
internal data format. The result is an application that treats internal
|
||||
data differently, depending on which code section is executing. The one or
|
||||
the other part of code will then, naturally, misinterpret the data.
|
||||
</p></td></tr></table></div><p>This example constructs a simple document, then adds content provided
|
||||
at the command line to the document's root element and outputs the results
|
||||
to <tt class="filename">stdout</tt> in the proper encoding. For this example, we
|
||||
use ISO-8859-1 encoding. The encoding of the string input at the command
|
||||
line is converted from ISO-8859-1 to UTF-8. Full code: <a href="apg.html" title="G. Code for Encoding Conversion Example">Appendix G, <i>Code for Encoding Conversion Example</i></a></p><p>The conversion, encapsulated in the example code in the
|
||||
<tt class="function">convert</tt> function, uses
|
||||
<span class="application">libxml's</span>
|
||||
<tt class="function">xmlFindCharEncodingHandler</tt> function:
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Retrieving Attributes</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s07.html" title="Writing Attribute"><link rel="next" href="ar01s09.html" title="Encoding Conversion"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Retrieving Attributes</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s07.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s09.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialattribute"></a>Retrieving Attributes</h2></div></div><div></div></div><p><a class="indexterm" name="id2814729"></a>
|
||||
Retrieving the value of an attribute is similar to the previous
|
||||
example in which we retrieved a node's text contents. In this case we'll
|
||||
extract the value of the <span class="acronym">URI</span> we added in the previous
|
||||
section. Full code: <a href="apg.html" title="G. Code for Retrieving Attribute Value Example">Appendix G, <i>Code for Retrieving Attribute Value Example</i></a>.</p><p>
|
||||
The initial steps for this example are similar to the previous ones: parse
|
||||
the doc, find the element you are interested in, then enter a function to
|
||||
carry out the specific task required. In this case, we call
|
||||
<tt class="function">getReference</tt>:
|
||||
</p><pre class="programlisting">
|
||||
<a name="handlerdatatype"></a><img src="images/callouts/1.png" alt="1" border="0">xmlCharEncodingHandlerPtr handler;
|
||||
<a name="calcsize"></a><img src="images/callouts/2.png" alt="2" border="0">size = (int)strlen(in)+1;
|
||||
out_size = size*2-1;
|
||||
out = malloc((size_t)out_size);
|
||||
void
|
||||
getReference (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
|
||||
…
|
||||
<a name="findhandlerfunction"></a><img src="images/callouts/3.png" alt="3" border="0">handler = xmlFindCharEncodingHandler(encoding);
|
||||
…
|
||||
<a name="callconversionfunction"></a><img src="images/callouts/4.png" alt="4" border="0">handler->input(out, &out_size, in, &temp);
|
||||
…
|
||||
<a name="outputencoding"></a><img src="images/callouts/5.png" alt="5" border="0">xmlSaveFormatFileEnc("-", doc, encoding, 1);
|
||||
xmlChar *uri;
|
||||
cur = cur->xmlChildrenNode;
|
||||
while (cur != NULL) {
|
||||
if ((!xmlStrcmp(cur->name, (const xmlChar *)"reference"))) {
|
||||
<a name="getattributevalue"></a><img src="images/callouts/1.png" alt="1" border="0"> uri = xmlGetProp(cur, "uri");
|
||||
printf("uri: %s\n", uri);
|
||||
xmlFree(uri);
|
||||
}
|
||||
cur = cur->next;
|
||||
}
|
||||
return;
|
||||
}
|
||||
</pre><p>
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#handlerdatatype"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p><tt class="varname">handler</tt> is declared as a pointer to an
|
||||
<tt class="function">xmlCharEncodingHandler</tt> function.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#calcsize"><img src="images/callouts/2.png" alt="2" border="0"></a> </td><td valign="top" align="left"><p>The <tt class="function">xmlCharEncodingHandler</tt> function needs
|
||||
to be given the size of the input and output strings, which are
|
||||
calculated here for strings <tt class="varname">in</tt> and
|
||||
<tt class="varname">out</tt>.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#findhandlerfunction"><img src="images/callouts/3.png" alt="3" border="0"></a> </td><td valign="top" align="left"><p><tt class="function">xmlFindCharEncodingHandler</tt> takes as its
|
||||
argument the data's initial encoding and searches
|
||||
<span class="application">libxml's</span> built-in set of conversion
|
||||
handlers, returning a pointer to the function or NULL if none is
|
||||
found.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#callconversionfunction"><img src="images/callouts/4.png" alt="4" border="0"></a> </td><td valign="top" align="left"><p>The conversion function identified by <tt class="varname">handler</tt>
|
||||
requires as its arguments pointers to the input and output strings,
|
||||
along with the length of each. The lengths must be determined
|
||||
separately by the application.</p></td></tr><tr><td width="5%" valign="top" align="left"><a href="#outputencoding"><img src="images/callouts/5.png" alt="5" border="0"></a> </td><td valign="top" align="left"><p>To output in a specified encoding rather than UTF-8, we use
|
||||
<tt class="function">xmlSaveFormatFileEnc</tt>, specifying the
|
||||
encoding.</p></td></tr></table></div><p>
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s07.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="apa.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Retrieving Attributes </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> A. Compilation</td></tr></table></div></body></html>
|
||||
|
||||
</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#getattributevalue"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>
|
||||
The key function is <tt class="function"><a href="http://xmlsoft.org/html/libxml-tree.html#XMLGETPROP" target="_top">xmlGetProp</a></tt>, which returns an
|
||||
<tt class="varname">xmlChar</tt> containing the attribute's value. In this case,
|
||||
we just print it out.
|
||||
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td colspan="2" align="left" valign="top"><p>
|
||||
If you are using a <span class="acronym">DTD</span> that declares a fixed or
|
||||
default value for the attribute, this function will retrieve it.
|
||||
</p></td></tr></table></div><p>
|
||||
</p></td></tr></table></div><p>
|
||||
|
||||
</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s07.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s09.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Writing Attribute </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Encoding Conversion</td></tr></table></div></body></html>
|
||||
|
||||
@ -1,5 +1,4 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Libxml Tutorial</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="next" href="ar01s02.html" title="Data Types"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Libxml Tutorial</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s02.html">Next</a></td></tr></table><hr></div><div class="article" lang="en"><div class="titlepage"><div><div><h1 class="title"><a name="id2759548"></a>Libxml Tutorial</h1></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="surname">Fleck</span></h3></div></div><div><p class="copyright">Copyright © 2002, 2003 John Fleck</p></div><div><div class="revhistory"><table border="1" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></tr><tr><td align="left">Revision 1</td><td align="left">June 4, 2002</td></tr><tr><td align="left" colspan="2">Initial draft</td></tr><tr><td align="left">Revision 2</td><td align="left">June 12, 2002</td></tr><tr><td align="left" colspan="2">retrieving attribute value added</td></tr><tr><td align="left">Revision 3</td><td align="left">Aug. 31, 2002</td></tr><tr><td align="left" colspan="2">freeing memory fix</td></tr><tr><td align="left">Revision 4</td><td align="left">Nov. 10, 2002</td></tr><tr><td align="left" colspan="2">encoding discussion added</td></tr><tr><td align="left">Revision 5</td><td align="left">Dec. 15, 2002</td></tr><tr><td align="left" colspan="2">more memory freeing changes</td></tr><tr><td align="left">Revision 6</td><td align="left">Jan. 26. 2003</td></tr><tr><td align="left" colspan="2">add index</td></tr><tr><td align="left">Revision 7</td><td align="left">April 25, 2003</td></tr><tr><td align="left" colspan="2">add compilation appendix</td></tr></table></div></div></div><div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="index.html#introduction">Introduction</a></dt><dt><a href="ar01s02.html">Data Types</a></dt><dt><a href="ar01s03.html">Parsing the file</a></dt><dt><a href="ar01s04.html">Retrieving Element Content</a></dt><dt><a href="ar01s05.html">Writing element content</a></dt><dt><a href="ar01s06.html">Writing Attribute</a></dt><dt><a href="ar01s07.html">Retrieving Attributes</a></dt><dt><a href="ar01s08.html">Encoding Conversion</a></dt><dt>A. <a href="apa.html">Compilation</a></dt><dt>B. <a href="apb.html">Sample Document</a></dt><dt>C. <a href="apc.html">Code for Keyword Example</a></dt><dt>D. <a href="apd.html">Code for Add Keyword Example</a></dt><dt>E. <a href="ape.html">Code for Add Attribute Example</a></dt><dt>F. <a href="apf.html">Code for Retrieving Attribute Value Example</a></dt><dt>G. <a href="apg.html">Code for Encoding Conversion Example</a></dt><dt>H. <a href="aph.html">Acknowledgements</a></dt><dt>I. <a href="ix01.html">Index</a></dt</dl></div><div class="abstract"><p class="title"><b>Abstract</b></p><p>Libxml is a freely licensed C language library for handling
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Libxml Tutorial</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="next" href="ar01s02.html" title="Data Types"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Libxml Tutorial</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s02.html">Next</a></td></tr></table><hr></div><div class="article" lang="en"><div class="titlepage"><div><div><h1 class="title"><a name="id2759589"></a>Libxml Tutorial</h1></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="surname">Fleck</span></h3></div></div><div><p class="copyright">Copyright © 2002, 2003 John Fleck</p></div><div><div class="revhistory"><table border="1" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></tr><tr><td align="left">Revision 1</td><td align="left">June 4, 2002</td></tr><tr><td align="left" colspan="2">Initial draft</td></tr><tr><td align="left">Revision 2</td><td align="left">June 12, 2002</td></tr><tr><td align="left" colspan="2">retrieving attribute value added</td></tr><tr><td align="left">Revision 3</td><td align="left">Aug. 31, 2002</td></tr><tr><td align="left" colspan="2">freeing memory fix</td></tr><tr><td align="left">Revision 4</td><td align="left">Nov. 10, 2002</td></tr><tr><td align="left" colspan="2">encoding discussion added</td></tr><tr><td align="left">Revision 5</td><td align="left">Dec. 15, 2002</td></tr><tr><td align="left" colspan="2">more memory freeing changes</td></tr><tr><td align="left">Revision 6</td><td align="left">Jan. 26. 2003</td></tr><tr><td align="left" colspan="2">add index</td></tr><tr><td align="left">Revision 7</td><td align="left">April 25, 2003</td></tr><tr><td align="left" colspan="2">add compilation appendix</td></tr><tr><td align="left">Revision 8</td><td align="left">July 24, 2003</td></tr><tr><td align="left" colspan="2">add XPath example</td></tr></table></div></div></div><div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="index.html#introduction">Introduction</a></dt><dt><a href="ar01s02.html">Data Types</a></dt><dt><a href="ar01s03.html">Parsing the file</a></dt><dt><a href="ar01s04.html">Retrieving Element Content</a></dt><dt><a href="ar01s05.html">Using XPath to Retrieve Element Content</a></dt><dt><a href="ar01s06.html">Writing element content</a></dt><dt><a href="ar01s07.html">Writing Attribute</a></dt><dt><a href="ar01s08.html">Retrieving Attributes</a></dt><dt><a href="ar01s09.html">Encoding Conversion</a></dt><dt>A. <a href="apa.html">Compilation</a></dt><dt>B. <a href="apb.html">Sample Document</a></dt><dt>C. <a href="apc.html">Code for Keyword Example</a></dt><dt>D. <a href="apd.html">Code for XPath Example</a></dt><dt>E. <a href="ape.html">Code for Add Keyword Example</a></dt><dt>F. <a href="apf.html">Code for Add Attribute Example</a></dt><dt>G. <a href="apg.html">Code for Retrieving Attribute Value Example</a></dt><dt>H. <a href="aph.html">Code for Encoding Conversion Example</a></dt><dt>I. <a href="api.html">Acknowledgements</a></dt></dl></div><div class="abstract"><p class="title"><b>Abstract</b></p><p>Libxml is a freely licensed C language library for handling
|
||||
<span class="acronym">XML</span>, portable across a large number of platforms. This
|
||||
tutorial provides examples of its basic functions.</p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="introduction"></a>Introduction</h2></div></div><div></div></div><p>Libxml is a C language library implementing functions for reading,
|
||||
creating and manipulating <span class="acronym">XML</span> data. This tutorial
|
||||
|
||||
@ -1,2 +1 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Index</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="aph.html" title="H. Acknowledgements"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Index</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="aph.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> </td></tr></table><hr></div><div class="index"><div class="titlepage"><div><div><h2 class="title"><a name="id2882914"></a>Index</h2></div></div><div></div></div><div class="index"><div class="indexdiv"><h3>A</h3><dl><dt>attribute</dt><dd><dl><dt>retrieving value, <a href="ar01s07.html">Retrieving Attributes</a></dt><dt>writing, <a href="ar01s06.html">Writing Attribute</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>C</h3><dl><dt>compiler flags, <a href="apa.html">Compilation</a></dt></dl></div><div class="indexdiv"><h3>E</h3><dl><dt>element</dt><dd><dl><dt>retrieving content, <a href="ar01s04.html">Retrieving Element Content</a></dt><dt>writing content, <a href="ar01s05.html">Writing element content</a></dt></dl></dd><dt>encoding, <a href="ar01s03.html">Parsing the file</a>, <a href="ar01s08.html">Encoding Conversion</a></dt></dl></div><div class="indexdiv"><h3>F</h3><dl><dt>file</dt><dd><dl><dt>parsing, <a href="ar01s03.html">Parsing the file</a>-<a href="ar01s03.html">Parsing the file</a></dt><dt>saving, <a href="ar01s05.html">Writing element content</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>X</h3><dl><dt>xmlChar, <a href="ar01s02.html">Data Types</a></dt><dt>xmlDoc, <a href="ar01s02.html">Data Types</a></dt><dt>xmlNodePtr, <a href="ar01s02.html">Data Types</a></dt></dl></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="aph.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> </td></tr><tr><td width="40%" align="left" valign="top">H. Acknowledgements </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> </td></tr></table></div></body></html>
|
||||
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Index</title><meta name="generator" content="DocBook XSL Stylesheets V1.60.1"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="api.html" title="I. Acknowledgements"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Index</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="api.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> </td></tr></table><hr></div><div class="index"><div class="titlepage"><div><div><h2 class="title"><a name="id2883028"></a>Index</h2></div></div><div></div></div><div class="index"><div class="indexdiv"><h3>A</h3><dl><dt>attribute</dt><dd><dl><dt>retrieving value, <a href="ar01s08.html">Retrieving Attributes</a></dt><dt>writing, <a href="ar01s07.html">Writing Attribute</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>C</h3><dl><dt>compiler flags, <a href="apa.html">Compilation</a></dt></dl></div><div class="indexdiv"><h3>E</h3><dl><dt>element</dt><dd><dl><dt>retrieving content, <a href="ar01s04.html">Retrieving Element Content</a></dt><dt>writing content, <a href="ar01s06.html">Writing element content</a></dt></dl></dd><dt>encoding, <a href="ar01s03.html">Parsing the file</a>, <a href="ar01s09.html">Encoding Conversion</a></dt></dl></div><div class="indexdiv"><h3>F</h3><dl><dt>file</dt><dd><dl><dt>parsing, <a href="ar01s03.html">Parsing the file</a>-<a href="ar01s03.html">Parsing the file</a></dt><dt>saving, <a href="ar01s06.html">Writing element content</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>X</h3><dl><dt>xmlChar, <a href="ar01s02.html">Data Types</a></dt><dt>xmlDoc, <a href="ar01s02.html">Data Types</a></dt><dt>xmlNodePtr, <a href="ar01s02.html">Data Types</a></dt></dl></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="api.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> </td></tr><tr><td width="40%" align="left" valign="top">I. Acknowledgements </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> </td></tr></table></div></body></html>
|
||||
|
||||
File diff suppressed because it is too large
Load Diff
@ -2,6 +2,7 @@
|
||||
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
||||
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
|
||||
<!ENTITY KEYWORD SYSTEM "includekeyword.c">
|
||||
<!ENTITY XPATH SYSTEM "includexpath.c">
|
||||
<!ENTITY STORY SYSTEM "includestory.xml">
|
||||
<!ENTITY ADDKEYWORD SYSTEM "includeaddkeyword.c">
|
||||
<!ENTITY ADDATTRIBUTE SYSTEM "includeaddattribute.c">
|
||||
@ -56,6 +57,11 @@
|
||||
<date>April 25, 2003</date>
|
||||
<revremark>add compilation appendix</revremark>
|
||||
</revision>
|
||||
<revision>
|
||||
<revnumber>8</revnumber>
|
||||
<date>July 24, 2003</date>
|
||||
<revremark>add XPath example</revremark>
|
||||
</revision>
|
||||
</revhistory>
|
||||
</articleinfo>
|
||||
<abstract>
|
||||
@ -321,20 +327,106 @@ parseStory (xmlDocPtr doc, xmlNodePtr cur) {
|
||||
</para>
|
||||
|
||||
</sect1>
|
||||
<sect1 id="xmltutorialxpath">
|
||||
<title>Using XPath to Retrieve Element Content</title>
|
||||
<para>In addition to walking the document tree to find an element,
|
||||
<application>Libxml2</application> includes support for
|
||||
use of <application>XPath</application> expressions to retrieve sets of
|
||||
nodes that match a specified criteria. Full documentation of the
|
||||
<application>XPath</application> <acronym>API</acronym> is <ulink
|
||||
url="http://xmlsoft.org/html/libxml-xpath.html">here</ulink>.
|
||||
</para>
|
||||
<para><application>XPath</application> allows searching through a document
|
||||
for nodes that match specified criteria. In the example below we search
|
||||
through a document for the contents of all <varname>keyword</varname>
|
||||
elements.
|
||||
<note>
|
||||
<para>A full discussion of <application>XPath</application> is beyond
|
||||
the scope of this document. For details on its use, see the <ulink
|
||||
url="http://www.w3.org/TR/xpath">XPath specification</ulink>.</para>
|
||||
</note>
|
||||
Full code for this example is at <xref linkend="xpathappendix" />.
|
||||
</para>
|
||||
<para>Using <application>XPath</application> requires setting up an
|
||||
xmlXPathContext and then supplying the <application>XPath</application>
|
||||
expression and the context to the
|
||||
<function>xmlXPathEvalExpression</function> function. The function returns
|
||||
an xmlXPathObjectPtr, which includes the set of nodes satisfying the
|
||||
<application>XPath</application> expression.</para>
|
||||
<para>
|
||||
<programlisting>
|
||||
xmlXPathObjectPtr
|
||||
getnodeset (xmlDocPtr doc, xmlChar *xpath){
|
||||
|
||||
<co id="cocontext" />xmlXPathContextPtr context;
|
||||
xmlXPathObjectPtr result;
|
||||
|
||||
<co id="cocreatecontext" />context = xmlXPathNewContext(doc);
|
||||
<co id="corunxpath" />result = xmlXPathEvalExpression(xpath, context);
|
||||
<co id="cocheckxpathresult" />if(xmlXPathNodeSetIsEmpty(result->nodesetval)){
|
||||
printf("No result\n");
|
||||
return NULL;
|
||||
}
|
||||
xmlXPathFreeContext(context);
|
||||
return result;
|
||||
</programlisting>
|
||||
<calloutlist>
|
||||
<callout arearefs="cocontext">
|
||||
<para>First we declare our variables.</para>
|
||||
</callout>
|
||||
<callout arearefs="cocreatecontext">
|
||||
<para>Initialize the <varname>context</varname> variable.</para>
|
||||
</callout>
|
||||
<callout arearefs="corunxpath">
|
||||
<para>Apply the <application>XPath</application> expression.</para>
|
||||
</callout>
|
||||
<callout arearefs="cocheckxpathresult">
|
||||
<para>Check the result.</para>
|
||||
</callout>
|
||||
</calloutlist>
|
||||
</para>
|
||||
<para>The xmlPathObjectPtr returned by the function contains a set of nodes
|
||||
and other information needed to iterate through the set and act on the
|
||||
results. For this example, our functions returns the
|
||||
<varname>xmlXPathObjectPtr</varname>. We use it to print the contents of
|
||||
<varname>keyword</varname> nodes in our document. The node set object
|
||||
includes the number of elements in the set (<varname>nodeNr</varname>) and
|
||||
an array of nodes (<varname>nodeTab</varname>):
|
||||
<programlisting>
|
||||
<co id="conodesetcounter" />for (i=0; i < nodeset->nodeNr; i++) {
|
||||
<co id="coprintkeywords" />keyword = xmlNodeListGetString(doc, nodeset->nodeTab[i]->xmlChildrenNode, 1);
|
||||
printf("keyword: %s\n", keyword);
|
||||
}
|
||||
</programlisting>
|
||||
<calloutlist>
|
||||
<callout arearefs="conodesetcounter">
|
||||
<para>The value of <varname>nodeset->Nr</varname> holds the number of
|
||||
elements in the node set. Here we use it to iterate through the array.</para>
|
||||
</callout>
|
||||
<callout arearefs="coprintkeywords">
|
||||
<para>Here we print the contents of each of the nodes returned.
|
||||
<note>
|
||||
<para>Note that we are printing the child node of the node that is
|
||||
returned, because the contents of the <varname>keyword</varname>
|
||||
element are a child text node.</para>
|
||||
</note>
|
||||
</para>
|
||||
</callout>
|
||||
</calloutlist>
|
||||
</para>
|
||||
</sect1>
|
||||
<sect1 id="xmltutorialwritingcontent">
|
||||
<title>Writing element content</title>
|
||||
<para><indexterm>
|
||||
<primary>element</primary>
|
||||
<secondary>writing content</secondary>
|
||||
</indexterm>
|
||||
Writing element content uses many of the same steps we used above
|
||||
— parsing the document and walking the tree. We parse the document,
|
||||
then traverse the tree to find the place we want to insert our element. For
|
||||
this example, we want to again find the "storyinfo" element and
|
||||
Writing element content uses many of the same steps we used above
|
||||
— parsing the document and walking the tree. We parse the document,
|
||||
then traverse the tree to find the place we want to insert our element. For
|
||||
this example, we want to again find the "storyinfo" element and
|
||||
this time insert a keyword. Then we'll write the file to disk. Full code:
|
||||
<xref linkend="addkeywordappendix" /></para>
|
||||
|
||||
<xref linkend="addkeywordappendix" /></para>
|
||||
<para>
|
||||
The main difference in this example is in
|
||||
<function>parseStory</function>:
|
||||
@ -597,6 +689,12 @@ Data encoding compatibility problems are one of the most common
|
||||
<programlisting>&KEYWORD;</programlisting>
|
||||
</para>
|
||||
</appendix>
|
||||
<appendix id="xpathappendix">
|
||||
<title>Code for XPath Example</title>
|
||||
<para>
|
||||
<programlisting>&XPATH;</programlisting>
|
||||
</para>
|
||||
</appendix>
|
||||
<appendix id="addkeywordappendix">
|
||||
<title>Code for Add Keyword Example</title>
|
||||
<para>
|
||||
@ -631,6 +729,7 @@ Data encoding compatibility problems are one of the most common
|
||||
<member>Christopher R. Harris</member>
|
||||
<member>Igor Zlatkovic</member>
|
||||
<member>Niraj Tolia</member>
|
||||
<member>David Turover</member>
|
||||
</simplelist>
|
||||
</para>
|
||||
</appendix>
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user