1<?xml version="1.0" encoding="UTF-8"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<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"> 4TD {font-family: Verdana,Arial,Helvetica} 5BODY {font-family: Verdana,Arial,Helvetica; margin-top: 2em; margin-left: 0em; margin-right: 0em} 6H1 {font-family: Verdana,Arial,Helvetica} 7H2 {font-family: Verdana,Arial,Helvetica} 8H3 {font-family: Verdana,Arial,Helvetica} 9A:link, A:visited, A:active { text-decoration: underline } 10</style><title>The SAX interface</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" 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href="http://cpan.uwinnipeg.ca/dist/XML-LibXML">Perl bindings</a></li><li><a href="https://libxmlplusplus.github.io/libxmlplusplus/">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="https://gitlab.gnome.org/GNOME/libxml2/issues">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>Sometimes the DOM tree output is just too large to fit reasonably into 11memory. In that case (and if you don't expect to save back the XML document 12loaded using libxml), it's better to use the SAX interface of libxml. SAX is 13a <strong>callback-based interface</strong> to the parser. Before parsing, 14the application layer registers a customized set of callbacks which are 15called by the library as it progresses through the XML input.</p><p>To get more detailed step-by-step guidance on using the SAX interface of 16libxml, see the <a href="http://www.jamesh.id.au/articles/libxml-sax/libxml-sax.html">nice 17documentation</a>.written by <a href="mailto:james@daa.com.au">James 18Henstridge</a>.</p><p>You can debug the SAX behaviour by using the <strong>testSAX</strong> 19program located in the gnome-xml module (it's usually not shipped in the 20binary packages of libxml, but you can find it in the tar source 21distribution). Here is the sequence of callbacks that would be reported by 22testSAX when parsing the example XML document shown earlier:</p><pre>SAX.setDocumentLocator() 23SAX.startDocument() 24SAX.getEntity(amp) 25SAX.startElement(EXAMPLE, prop1='gnome is great', prop2='&amp; linux too') 26SAX.characters( , 3) 27SAX.startElement(head) 28SAX.characters( , 4) 29SAX.startElement(title) 30SAX.characters(Welcome to Gnome, 16) 31SAX.endElement(title) 32SAX.characters( , 3) 33SAX.endElement(head) 34SAX.characters( , 3) 35SAX.startElement(chapter) 36SAX.characters( , 4) 37SAX.startElement(title) 38SAX.characters(The Linux adventure, 19) 39SAX.endElement(title) 40SAX.characters( , 4) 41SAX.startElement(p) 42SAX.characters(bla bla bla ..., 15) 43SAX.endElement(p) 44SAX.characters( , 4) 45SAX.startElement(image, href='linus.gif') 46SAX.endElement(image) 47SAX.characters( , 4) 48SAX.startElement(p) 49SAX.characters(..., 3) 50SAX.endElement(p) 51SAX.characters( , 3) 52SAX.endElement(chapter) 53SAX.characters( , 1) 54SAX.endElement(EXAMPLE) 55SAX.endDocument()</pre><p>Most of the other interfaces of libxml2 are based on the DOM tree-building 56facility, so nearly everything up to the end of this document presupposes the 57use of the standard DOM tree build. Note that the DOM tree itself is built by 58a set of registered default callbacks, without internal specific 59interface.</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> 60
