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| <html><head><meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"><title>Retrieving Element Content</title><meta name="generator" content="DocBook XSL Stylesheets V1.48"><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"><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="xmltutorialgettext"></a>Retrieving Element Content</h2></div></div><p>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 |
| process to find the node we are interested in involves tediously walking the |
| tree. We assume you already have an xmlDocPtr called <tt>doc</tt> |
| and an xmlNodPtr called <tt>cur</tt>.</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"))){ |
| parseStory (doc, cur); |
| } |
| |
| cur = cur->next; |
| } |
| |
| </pre> |
| |
| <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>cur</tt>. At this |
| point, <tt>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 |
| looking for. It uses the libxml string |
| comparison |
| function, <tt><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>parseStory</tt>.</p></td></tr></table></div> |
| </p><p> |
| <pre class="programlisting"> |
| void |
| parseStory (xmlDocPtr doc, xmlNodePtr cur) { |
| |
| <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"))) { |
| <a name="foundkeyword"></a><img src="images/callouts/3.png" alt="3" border="0"> printf("keyword: %s\n", xmlNodeListGetString(doc, cur->xmlChildrenNode, 1)); |
| } |
| cur = cur->next; |
| } |
| return; |
| } |
| </pre> |
| <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 |
| its contents. Remember that in XML, the text |
| contained within an element is a child node of that element, so we |
| turn to <tt>cur->xmlChildrenNode</tt>. To retrieve it, we |
| use the function <tt><a href="http://xmlsoft.org/html/libxml-tree.html#XMLNODELISTGETSTRING" target="_top">xmlNodeListGetString</a></tt>, which also takes the <tt>doc</tt> pointer as an argument. In this case, we just print it out.</p></td></tr></table></div> |
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