xml_set_end_namespace_decl_handler()
The xml_set_end_namespace_decl_handler() function is a PHP built-in function that sets a user-defined function as the handler for end namespace declarations in an XML parser. This function is part of the SAX XML parser extension and is used to set a custom callback for when the parser encounters the end of a namespace declaration.
The xml extension must be enabled for this function to work. It is useful when you need to process namespace information during SAX parsing, for example, to track or store namespace mappings.
Syntax
The syntax of the xml_set_end_namespace_decl_handler() function is as follows:
Setting an end namespace declaration handler
xml_set_end_namespace_decl_handler($parser, $handler)Where $parser is the XML parser resource created by xml_parser_create(), and $handler is the name of the user-defined function that will handle the end of a namespace declaration.
Usage Examples
Let's take a look at a practical example of using xml_set_end_namespace_decl_handler() in PHP.
Example: Setting an End Namespace Declaration Handler Function
The following example demonstrates how to set up the handler and actually trigger it by parsing a sample XML string. Note that the handler is called during the xml_parse() process.
Parsing XML with an end namespace declaration handler
function handle_end_namespace_decl($parser, $prefix) {
echo "End of namespace prefix: $prefix\n";
}
$xml_parser = xml_parser_create();
xml_set_end_namespace_decl_handler($xml_parser, "handle_end_namespace_decl");
$xml_data = '<?xml version="1.0"?><root xmlns:ns="http://example.com"><ns:child/></root>';
xml_parse($xml_parser, $xml_data, true);
xml_parser_free($xml_parser);This code creates a new XML parser using xml_parser_create(), sets the custom handler, and then parses an XML string with xml_parse(). The handler will be triggered when the parser reaches the end of the namespace declaration. You can replace the echo statement with logic to store namespace information or perform other actions.
Conclusion
In this article, we've discussed PHP's xml_set_end_namespace_decl_handler() function and how it integrates into the SAX XML parser workflow. We've explained its syntax and provided a complete example showing how to set the handler and trigger it during parsing. By using xml_set_end_namespace_decl_handler() in your PHP applications, you can reliably process namespace declarations as they are encountered during SAX parsing.
Practice
What is the function of xml_set_end_namespace_decl_handler() in PHP?