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diff --git a/libxml2/doc/example.html b/libxml2/doc/example.html new file mode 100644 index 0000000..50668bf --- /dev/null +++ b/libxml2/doc/example.html @@ -0,0 +1,187 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="SHORTCUT ICON" href="/favicon.ico" /><style type="text/css"> +TD {font-family: Verdana,Arial,Helvetica} +BODY {font-family: Verdana,Arial,Helvetica; margin-top: 2em; margin-left: 0em; margin-right: 0em} +H1 {font-family: Verdana,Arial,Helvetica} +H2 {font-family: Verdana,Arial,Helvetica} +H3 {font-family: Verdana,Arial,Helvetica} +A:link, A:visited, A:active { text-decoration: underline } +</style><title>A real example</title></head><body bgcolor="#8b7765" text="#000000" link="#a06060" vlink="#000000"><table border="0" width="100%" cellpadding="5" cellspacing="0" align="center"><tr><td width="120"><a href="http://swpat.ffii.org/"><img src="epatents.png" alt="Action against software patents" /></a></td><td width="180"><a href="http://www.gnome.org/"><img src="gnome2.png" alt="Gnome2 Logo" /></a><a href="http://www.w3.org/Status"><img src="w3c.png" alt="W3C Logo" /></a><a href="http://www.redhat.com/"><img src="redhat.gif" alt="Red Hat Logo" /></a><div align="left"><a href="http://xmlsoft.org/"><img src="Libxml2-Logo-180x168.gif" alt="Made with Libxml2 Logo" /></a></div></td><td><table border="0" width="90%" cellpadding="2" cellspacing="0" align="center" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3" bgcolor="#fffacd"><tr><td align="center"><h1>The XML C parser and toolkit of Gnome</h1><h2>A real example</h2></td></tr></table></td></tr></table></td></tr></table><table border="0" cellpadding="4" cellspacing="0" width="100%" align="center"><tr><td bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="2" width="100%"><tr><td valign="top" width="200" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Developer Menu</b></center></td></tr><tr><td bgcolor="#fffacd"><form action="search.php" enctype="application/x-www-form-urlencoded" method="get"><input name="query" type="text" size="20" value="" /><input name="submit" type="submit" value="Search ..." /></form><ul><li><a href="index.html" style="font-weight:bold">Main Menu</a></li><li><a href="html/index.html" style="font-weight:bold">Reference Manual</a></li><li><a href="examples/index.html" style="font-weight:bold">Code Examples</a></li><li><a href="guidelines.html">XML Guidelines</a></li><li><a href="tutorial/index.html">Tutorial</a></li><li><a href="xmlreader.html">The Reader Interface</a></li><li><a href="ChangeLog.html">ChangeLog</a></li><li><a href="XSLT.html">XSLT</a></li><li><a href="python.html">Python and bindings</a></li><li><a href="architecture.html">libxml2 architecture</a></li><li><a href="tree.html">The tree output</a></li><li><a href="interface.html">The SAX interface</a></li><li><a href="xmlmem.html">Memory Management</a></li><li><a href="xmlio.html">I/O Interfaces</a></li><li><a href="library.html">The parser interfaces</a></li><li><a href="entities.html">Entities or no entities</a></li><li><a href="namespaces.html">Namespaces</a></li><li><a href="upgrade.html">Upgrading 1.x code</a></li><li><a href="threads.html">Thread safety</a></li><li><a href="DOM.html">DOM Principles</a></li><li><a href="example.html">A real example</a></li><li><a href="xml.html">flat page</a>, <a href="site.xsl">stylesheet</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>API Indexes</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="APIchunk0.html">Alphabetic</a></li><li><a href="APIconstructors.html">Constructors</a></li><li><a href="APIfunctions.html">Functions/Types</a></li><li><a href="APIfiles.html">Modules</a></li><li><a href="APIsymbols.html">Symbols</a></li></ul></td></tr></table><table width="100%" border="0" cellspacing="1" cellpadding="3"><tr><td colspan="1" bgcolor="#eecfa1" align="center"><center><b>Related links</b></center></td></tr><tr><td bgcolor="#fffacd"><ul><li><a href="http://mail.gnome.org/archives/xml/">Mail archive</a></li><li><a href="http://xmlsoft.org/XSLT/">XSLT libxslt</a></li><li><a href="http://phd.cs.unibo.it/gdome2/">DOM gdome2</a></li><li><a href="http://www.aleksey.com/xmlsec/">XML-DSig xmlsec</a></li><li><a href="ftp://xmlsoft.org/">FTP</a></li><li><a href="http://www.zlatkovic.com/projects/libxml/">Windows binaries</a></li><li><a href="http://opencsw.org/packages/libxml2">Solaris binaries</a></li><li><a href="http://www.explain.com.au/oss/libxml2xslt.html">MacOsX binaries</a></li><li><a href="http://lxml.de/">lxml Python bindings</a></li><li><a href="http://cpan.uwinnipeg.ca/dist/XML-LibXML">Perl bindings</a></li><li><a href="http://libxmlplusplus.sourceforge.net/">C++ bindings</a></li><li><a href="http://www.zend.com/php5/articles/php5-xmlphp.php#Heading4">PHP bindings</a></li><li><a href="http://sourceforge.net/projects/libxml2-pas/">Pascal bindings</a></li><li><a href="http://libxml.rubyforge.org/">Ruby bindings</a></li><li><a href="http://tclxml.sourceforge.net/">Tcl bindings</a></li><li><a href="http://bugzilla.gnome.org/buglist.cgi?product=libxml2">Bug Tracker</a></li></ul></td></tr></table></td></tr></table></td><td valign="top" bgcolor="#8b7765"><table border="0" cellspacing="0" cellpadding="1" width="100%"><tr><td><table border="0" cellspacing="0" cellpadding="1" width="100%" bgcolor="#000000"><tr><td><table border="0" cellpadding="3" cellspacing="1" width="100%"><tr><td bgcolor="#fffacd"><p>Here is a real size example, where the actual content of the application +data is not kept in the DOM tree but uses internal structures. It is based on +a proposal to keep a database of jobs related to Gnome, with an XML based +storage structure. Here is an <a href="gjobs.xml">XML encoded jobs +base</a>:</p><pre><?xml version="1.0"?> +<gjob:Helping xmlns:gjob="http://www.gnome.org/some-location"> + <gjob:Jobs> + + <gjob:Job> + <gjob:Project ID="3"/> + <gjob:Application>GBackup</gjob:Application> + <gjob:Category>Development</gjob:Category> + + <gjob:Update> + <gjob:Status>Open</gjob:Status> + <gjob:Modified>Mon, 07 Jun 1999 20:27:45 -0400 MET DST</gjob:Modified> + <gjob:Salary>USD 0.00</gjob:Salary> + </gjob:Update> + + <gjob:Developers> + <gjob:Developer> + </gjob:Developer> + </gjob:Developers> + + <gjob:Contact> + <gjob:Person>Nathan Clemons</gjob:Person> + <gjob:Email>nathan@windsofstorm.net</gjob:Email> + <gjob:Company> + </gjob:Company> + <gjob:Organisation> + </gjob:Organisation> + <gjob:Webpage> + </gjob:Webpage> + <gjob:Snailmail> + </gjob:Snailmail> + <gjob:Phone> + </gjob:Phone> + </gjob:Contact> + + <gjob:Requirements> + The program should be released as free software, under the GPL. + </gjob:Requirements> + + <gjob:Skills> + </gjob:Skills> + + <gjob:Details> + A GNOME based system that will allow a superuser to configure + compressed and uncompressed files and/or file systems to be backed + up with a supported media in the system. This should be able to + perform via find commands generating a list of files that are passed + to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine + or via operations performed on the filesystem itself. Email + notification and GUI status display very important. + </gjob:Details> + + </gjob:Job> + + </gjob:Jobs> +</gjob:Helping></pre><p>While loading the XML file into an internal DOM tree is a matter of +calling only a couple of functions, browsing the tree to gather the data and +generate the internal structures is harder, and more error prone.</p><p>The suggested principle is to be tolerant with respect to the input +structure. For example, the ordering of the attributes is not significant, +the XML specification is clear about it. It's also usually a good idea not to +depend on the order of the children of a given node, unless it really makes +things harder. Here is some code to parse the information for a person:</p><pre>/* + * A person record + */ +typedef struct person { + char *name; + char *email; + char *company; + char *organisation; + char *smail; + char *webPage; + char *phone; +} person, *personPtr; + +/* + * And the code needed to parse it + */ +personPtr parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { + personPtr ret = NULL; + +DEBUG("parsePerson\n"); + /* + * allocate the struct + */ + ret = (personPtr) malloc(sizeof(person)); + if (ret == NULL) { + fprintf(stderr,"out of memory\n"); + return(NULL); + } + memset(ret, 0, sizeof(person)); + + /* We don't care what the top level element name is */ + cur = cur->xmlChildrenNode; + while (cur != NULL) { + if ((!strcmp(cur->name, "Person")) && (cur->ns == ns)) + ret->name = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); + if ((!strcmp(cur->name, "Email")) && (cur->ns == ns)) + ret->email = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); + cur = cur->next; + } + + return(ret); +}</pre><p>Here are a couple of things to notice:</p><ul> + <li>Usually a recursive parsing style is the more convenient one: XML data + is by nature subject to repetitive constructs and usually exhibits highly + structured patterns.</li> + <li>The two arguments of type <em>xmlDocPtr</em> and <em>xmlNsPtr</em>, + i.e. the pointer to the global XML document and the namespace reserved to + the application. Document wide information are needed for example to + decode entities and it's a good coding practice to define a namespace for + your application set of data and test that the element and attributes + you're analyzing actually pertains to your application space. This is + done by a simple equality test (cur->ns == ns).</li> + <li>To retrieve text and attributes value, you can use the function + <em>xmlNodeListGetString</em> to gather all the text and entity reference + nodes generated by the DOM output and produce an single text string.</li> +</ul><p>Here is another piece of code used to parse another level of the +structure:</p><pre>#include <libxml/tree.h> +/* + * a Description for a Job + */ +typedef struct job { + char *projectID; + char *application; + char *category; + personPtr contact; + int nbDevelopers; + personPtr developers[100]; /* using dynamic alloc is left as an exercise */ +} job, *jobPtr; + +/* + * And the code needed to parse it + */ +jobPtr parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) { + jobPtr ret = NULL; + +DEBUG("parseJob\n"); + /* + * allocate the struct + */ + ret = (jobPtr) malloc(sizeof(job)); + if (ret == NULL) { + fprintf(stderr,"out of memory\n"); + return(NULL); + } + memset(ret, 0, sizeof(job)); + + /* We don't care what the top level element name is */ + cur = cur->xmlChildrenNode; + while (cur != NULL) { + + if ((!strcmp(cur->name, "Project")) && (cur->ns == ns)) { + ret->projectID = xmlGetProp(cur, "ID"); + if (ret->projectID == NULL) { + fprintf(stderr, "Project has no ID\n"); + } + } + if ((!strcmp(cur->name, "Application")) && (cur->ns == ns)) + ret->application = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); + if ((!strcmp(cur->name, "Category")) && (cur->ns == ns)) + ret->category = xmlNodeListGetString(doc, cur->xmlChildrenNode, 1); + if ((!strcmp(cur->name, "Contact")) && (cur->ns == ns)) + ret->contact = parsePerson(doc, ns, cur); + cur = cur->next; + } + + return(ret); +}</pre><p>Once you are used to it, writing this kind of code is quite simple, but +boring. Ultimately, it could be possible to write stubbers taking either C +data structure definitions, a set of XML examples or an XML DTD and produce +the code needed to import and export the content between C data and XML +storage. This is left as an exercise to the reader :-)</p><p>Feel free to use <a href="example/gjobread.c">the code for the full C +parsing example</a> as a template, it is also available with Makefile in the +Gnome SVN base under libxml2/example</p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html> |