PHP Function Reference

PHP xml_set_start_namespace_decl_handler() Function



The PHP xml_set_start_namespace_decl_handler() function sets start namespace declaration handler function for the given XML parser. Namespace declarations occur inside start tags. But the namespace declaration start handler is called before the start tag handler for each namespace declared in that start tag.

Syntax

xml_set_start_namespace_decl_handler(parser, handler)

Parameters

parser Required. Specify a reference to the XML parser to set up start namespace declaration handler function.
handler Required. Specify a string containing the name of a function to be used as an event handler. The function must accept three parameters:
handler(parser, prefix, uri)
  • parser: The first parameter, parser, is a reference to the XML parser calling the handler.
  • prefix: The prefix is a string used to reference the namespace within an XML object.
  • uri: The Uniform Resource Identifier (URI) of the namespace.
If a handler function is set to an empty string, or false, the handler in question is disabled. Note: Instead of a function name, an array containing an object reference and a method name can also be supplied.

Return Value

Returns true on success or false on failure.

Example: xml_set_start_namespace_decl_handler() example

Lets assume that we have a file called test.xml. In the example below, an XML parser is created using xml_parser_create() function. Then the XML file is opened to parse its data using character handler function char_print. Then the start_ns and end_ns functions are set as start and end namespace declaration handler function respectively for XML parser. After parsing the document, the parser is freed using xml_parser_free() function.

<?php
//create an XML parser
$parser=xml_parser_create();

//character handler function for XML parser
function char_print($parser, $data) {
  echo $data;
}

//start namespace declaration handler function for XML parser
function start_ns($parser, $prefix, $uri) {
  echo "$prefix $uri \n";
}

//end namespace declaration handler function for XML parser
function end_ns($parser, $prefix) {
  echo "$prefix \n";
}

//set the character handler function for XML parser
xml_set_character_data_handler($parser,"char_print");

//set the start and end namespace declaration 
//handler function for XML parser
xml_set_start_namespace_decl_handler($parser, "start_ns");
xml_set_end_namespace_decl_handler($parser, "end_ns");

//opening xml file
$fp = fopen("test.xml", "r");

while($data = fread($fp,4096)) {
  //parsing XML data
  xml_parse($parser,$data,feof($fp)) or

    //displaying error when parse error occurs
    die (sprintf("XML Error: %s at line %d",

    //error string
    xml_error_string(xml_get_error_code($parser)),

    //current line
    xml_get_current_line_number($parser)));
}

//free XML parser
xml_parser_free($parser);

fclose($fp);
?>

❮ PHP XML Parser Reference