PHP XML Parser

Last Updated : 29 Jul, 2021

An example to show XML element's structure

<?php

$file = "data.xml";
$depth = array();

function startElement($parser, $name, $attrs)
{
    global $depth;

    if (!isset($depth[$parser])) {
        $depth[$parser] = 0;
    }

    for ($i = 0; $i < $depth[$parser]; $i++) {
        echo "  ";
    }
    echo "$name\n";
    $depth[$parser]++;
}

function endElement($parser, $name)
{
    global $depth;
    $depth[$parser]--;
}

$xml_parser = xml_parser_create();
xml_set_element_handler($xml_parser, "startElement", "endElement");
if (!($fp = fopen($file, "r"))) {
    die("could not open XML input");
}

while ($data = fread($fp, 4096)) {
    if (!xml_parse($xml_parser, $data, feof($fp))) {
        die(sprintf("XML error: %s at line %d",
                    xml_error_string(xml_get_error_code($xml_parser)),
                    xml_get_current_line_number($xml_parser)));
    }
}
xml_parser_free($xml_parser);

?>

Requirements

This extension requires the libxml PHP extension.

This means that passing in --enable-libxml is also required, although this is implicitly accomplished because libxml is enabled by default.

This extension uses an expat compat layer by default. It can use also expat, which can be found at » http://www.jclark.com/xml/expat.html.

The Makefile that comes with expat does not build a library by default, you can use this make rule for that:

Installation

This extension is enabled by default. It may be disabled by using the following option at compile time: --disable-xml.

These functions are enabled by default, using the bundled expat library.

You can disable XML support with --disable-xml. If you compile PHP as a module for Apache 1.3.9 or later, PHP will automatically use the bundled expat library from Apache.

If you don't want to use the bundled expat library, configure PHP with --with-expat-dir=DIR , where DIR should point to the base installation directory of expat.

The Windows version of PHP has built-in support for this extension.

You do not need to load any additional extensions in order to use these functions.

Run-time Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

The xml resource as returned by xml_parser_create() and xml_parser_create_ns() references an xml parser instance to be used with the functions provided by this extension.

Predefined Constants

This XML Parser extension also provided some predefined constants.

In order to use this extension has either been compiled into PHP or dynamically loaded at runtime.

XML_ERROR_NONE (integer)
XML_ERROR_NO_MEMORY (integer)
XML_ERROR_SYNTAX (integer)
XML_ERROR_NO_ELEMENTS (integer)
XML_ERROR_INVALID_TOKEN (integer)
XML_ERROR_UNCLOSED_TOKEN (integer)
XML_ERROR_PARTIAL_CHAR (integer)
XML_ERROR_TAG_MISMATCH (integer)
XML_ERROR_DUPLICATE_ATTRIBUTE (integer)
XML_ERROR_JUNK_AFTER_DOC_ELEMENT (integer)
XML_ERROR_PARAM_ENTITY_REF (integer)
XML_ERROR_UNDEFINED_ENTITY (integer)
XML_ERROR_RECURSIVE_ENTITY_REF (integer)
XML_ERROR_ASYNC_ENTITY (integer)
XML_ERROR_BAD_CHAR_REF (integer)
XML_ERROR_BINARY_ENTITY_REF (integer)
XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF (integer)
XML_ERROR_MISPLACED_XML_PI (integer)
XML_ERROR_UNKNOWN_ENCODING (integer)
XML_ERROR_INCORRECT_ENCODING (integer)
XML_ERROR_UNCLOSED_CDATA_SECTION (integer)
XML_ERROR_EXTERNAL_ENTITY_HANDLING (integer)
XML_OPTION_CASE_FOLDING (integer)
XML_OPTION_TARGET_ENCODING (integer)
XML_OPTION_SKIP_TAGSTART (integer)
XML_OPTION_SKIP_WHITE (integer)
XML_SAX_IMPL (string)

XML Parser Error Codes

These constants defined to show XML error codes.

XML_ERROR_NONE
XML_ERROR_NO_MEMORY
XML_ERROR_SYNTAX
XML_ERROR_NO_ELEMENTS
XML_ERROR_INVALID_TOKEN
XML_ERROR_UNCLOSED_TOKEN
XML_ERROR_PARTIAL_CHAR
XML_ERROR_TAG_MISMATCH
XML_ERROR_DUPLICATE_ATTRIBUTE
XML_ERROR_JUNK_AFTER_DOC_ELEMENT
XML_ERROR_PARAM_ENTITY_REF
XML_ERROR_UNDEFINED_ENTITY
XML_ERROR_RECURSIVE_ENTITY_REF
XML_ERROR_ASYNC_ENTITY
XML_ERROR_BAD_CHAR_REF
XML_ERROR_BINARY_ENTITY_REF
XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF
XML_ERROR_MISPLACED_XML_PI
XML_ERROR_UNKNOWN_ENCODING
XML_ERROR_INCORRECT_ENCODING
XML_ERROR_UNCLOSED_CDATA_SECTION
XML_ERROR_EXTERNAL_ENTITY_HANDLING

XML Parser Functions

utf8_decode — Converts a string with ISO-8859-1 characters encoded with UTF-8 to single-byte ISO-8859-1
utf8_encode — Encodes an ISO-8859-1 string to UTF-8
xml_error_string — Get XML parser error string
xml_get_current_byte_index — Get current byte index for an XML parser
xml_get_current_column_number — Get current column number for an XML parser
xml_get_current_line_number — Get current line number for an XML parser
xml_get_error_code — Get XML parser error code
xml_parse_into_struct — Parse XML data into an array structure
xml_parse — Start parsing an XML document
xml_parser_create_ns — Create an XML parser with namespace support
xml_parser_create — Create an XML parser
xml_parser_free — Free an XML parser
xml_parser_get_option — Get options from an XML parser
xml_parser_set_option — Set options in an XML parser
xml_set_character_data_handler — Set up character data handler
xml_set_default_handler — Set up default handler
xml_set_element_handler — Set up start and end element handlers
xml_set_end_namespace_decl_handler — Set up end namespace declaration handler
xml_set_external_entity_ref_handler — Set up external entity reference handler
xml_set_notation_decl_handler — Set up notation declaration handler
xml_set_object — Use XML Parser within an object
xml_set_processing_instruction_handler — Set up processing instruction (PI) handler
xml_set_start_namespace_decl_handler — Set up start namespace declaration handler
xml_set_unparsed_entity_decl_handler — Set up unparsed entity declaration handler