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C # tutorial
The built-in XML Expat Parser makes it possible to process XML documents in PHP
The Expat parser is an event-based parser.
Look at the following XML fraction:
An event-based parser reports the XML above as a series of three events:
The XML Expat Parser functions are part of the PHP core. There is no installation needed to use these functions.
The XML file "note.xml" will be used in the example below:
We want to initialize the XML Expat Parser in PHP, define some handlers for different XML events, and then parse the XML file.
<?php
// Initialize the XML parser
$parser=xml_parser_create();
// Function to use at the start of an element
function start($parser,$element_name,$element_attrs) {
switch($element_name) {
case "NOTE":
echo "-- Note --<br>";
break;
case "TO":
echo "To: ";
break;
case "FROM":
echo "From: ";
break;
case "HEADING":
echo "Heading: ";
break;
case "BODY":
echo "Message: ";
}
}
// Function to use at the end of an element
function stop($parser,$element_name) {
echo "<br>";
}
// Function to use when finding character data
function char($parser,$data) {
echo $data;
}
// Specify element handler
xml_set_element_handler($parser,"start","stop");
// Specify data handler
xml_set_character_data_handler($parser,"char");
// Open XML file
$fp=fopen("note.xml","r");
// Read data
while ($data=fread($fp,4096)) {
xml_parse($parser,$data,feof($fp)) or
die (sprintf("XML Error: %s at line %d",
xml_error_string(xml_get_error_code($parser)),
xml_get_current_line_number($parser)));
}
// Free the XML parser
xml_parser_free($parser);
?>
Example explained:
xml_parser_create()
functionxml_set_element_handler()
function to specify which function will be executed when the parser encounters the opening and closing tagsxml_set_character_data_handler()
function to specify which function will execute when the parser encounters character dataxml_parse()
functionxml_error_string()
function to convert an XML error to a textual descriptionxml_parser_free()
function to release the memory allocated with the xml_parser_create()
functionFor more information about the PHP Expat functions, visit our PHP XML Parser Reference.