libxmlop -- A libxml SAX driver for PyXML

• What Is libxmlop?
• Installation
• Calling and Using libxmlop
• Extensions
• Additional Information

What Is libxmlop?

libxmlop is a SAX2 driver for PyXML. It is implemented on top of the libxml XML parser.

libxmlop exposes the standard Python SAX2 interface and callbacks plus a few additional capabilities, which are described below.

You can learn more about libxml at http://xmlsoft.org/.

Installation

1. Download and build and install libxml2. You can find it http://www.xmlsoft.org.

   Note that on my machine I had to add the directory containing the installed libraries to the environment variable LD_LIBRARY_PATH. For example:

       export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
   

2. Change directory to the PyXML directory and unzip the libxmlop distribution. Something like the following:

   NOTE! The following replaces setup.py. If you have modified that file or have a version other than PyXML-0.7, you may want to patch in the libxmlop stanza instead.

       cd /Python/PyXML-0.7
       unzip ../libxmlop.zip
   

3. Build and install libxmlop with the regular Distutils commands:

       python setup.py build
       python setup.py install
   

Calling and Using libxmlop

Use that standard Python SAX2 interface.

Extensions

libxmlop provides the following functions not provided by the standard SAX2 interface.

activateEventHandler

Turn a SAX2 callback off or on. After turning a call-back off, the content handler will not receive events for that call-back.

    parser.activateEventHandler(callback_name, flag)

Where:

• callback_name is the name of the SAX2 call-back, e.g. "characters" or "endElement".
• flag is either 0 or 1. 0 turns the call-back off; 1 turns it on.

Example:

    import xml.sax

    class ContentHandler:
        def __init__(self, parser):
            self.parser = parser
            self.target = ''
        def startDocument(self):
            self.parser.activateEventHandler('characters', 0)
        def startElement(self, name, attrs):
            if name == 'target':
                self.parser.activateEventHandler('characters', 1)
        def endElement(self, name, attrs):
            if name == 'target':
                self.parser.activateEventHandler('characters', 0)
        def characters(self, data):
            self.target += data

    def test(inFileName):
        parser = xml.sax.make_parser('xml.sax.drivers2.drv_libxmlop')
        handler = ContentHandler(parser)
        parser.setContentHandler(handler)
        parser.parse(inFileName)

Additional Information

You can find more information about libxml at http://xmlsoft.org.

More information about PyXML is at http://www.python.org/sigs/xml-sig/.

Last update: 4/11/02