Page 621 - Beginning PHP 5.3

Chapter 19: Working with XML
Creating Event Handlers

Now that you have a parser to work with, you need to create functions to handle the start of an XML
element, the end of an element, and character data.

The function that deals with the start of an element needs to accept three arguments: the parser resource,
the element name, and an associative array of any attributes in the element. For example:
function startElementHandler( $parser, $element, $attributes )
{
// (process the start of the element)
}

The end - element handler is similar, but it doesn ’ t have to deal with attributes:
function endElementHandler( $parser, $element )
{
// (process the end of the element)
}

Finally, the character data handler needs to accept the parser resource, and a string containing the
character data. For example:

function characterDataHandler( $parser, $data )
{
// (process the character data)

}
Obviously the example handlers don ’ t do any actual processing of the elements or data. You write real
handlers in a moment.

Once you ’ ve created your three event handlers, you register them with the parser. To register the start
and end handlers use xml_set_element_handler() , passing in the parser resource, followed by the
names of the start element handler and end element handler functions as strings. For example:

xml_set_element_handler( $parser, “startElementHandler”, “endElementHandler” );
To register the character data handler call xml_set_character_data_handler() , passing in the parser
resource followed by the handler function ’ s name as a string:
xml_set_character_data_handler( $parser, “characterDataHandler” );

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