IXR_Message::parse()

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Performance profile

How much work a call to IXR_Message::parse() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with how much data it finds.

Instructions

24–155

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 162.

Plugin surface

2 hooks

Third-party callbacks on 'xmlrpc_element_limit', 'xmlrpc_chunk_parsing_size' run inside this call, and their cost is not bounded by anything here.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach query, option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 9 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost IXR_Message::parse() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 2

2 hooks fire while IXR_Message::parse() runs, in this order:

1. 1
   apply_filters( xmlrpc_element_limit )filterline 86 (+41 into the body)

   Filters the number of elements to parse in an XML-RPC response.

2. 2
   apply_filters( xmlrpc_chunk_parsing_size )filterline 109 (+64 into the body)

   Filters the chunk size that can be used to parse an XML-RPC response message.

Uses · 2

• __()Retrieves the translation of $text.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Source code

View on Trac ↗View on GitHub ↗

45    function parse()46    {47        if ( ! function_exists( 'xml_parser_create' ) ) {48            trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );49            return false;50        }51 52        // first remove the XML declaration53        // merged from WP #10698 - this method avoids the RAM usage of preg_replace on very large messages54        $header = preg_replace( '/<\?xml.*?\?'.'>/s', '', substr( $this->message, 0, 100 ), 1 );55        $this->message = trim( substr_replace( $this->message, $header, 0, 100 ) );56        if ( '' == $this->message ) {57            return false;58        }59 60        // Then remove the DOCTYPE61        $header = preg_replace( '/^<!DOCTYPE[^>]*+>/i', '', substr( $this->message, 0, 200 ), 1 );62        $this->message = trim( substr_replace( $this->message, $header, 0, 200 ) );63        if ( '' == $this->message ) {64            return false;65        }66 67        // Check that the root tag is valid68        $root_tag = substr( $this->message, 0, strcspn( substr( $this->message, 0, 20 ), "> \t\r\n" ) );69        if ( '<!DOCTYPE' === strtoupper( $root_tag ) ) {70            return false;71        }72        if ( ! in_array( $root_tag, array( '<methodCall', '<methodResponse', '<fault' ) ) ) {73            return false;74        }75 76        // Bail if there are too many elements to parse77        $element_limit = 30000;78        if ( function_exists( 'apply_filters' ) ) {79            /**80             * Filters the number of elements to parse in an XML-RPC response.81             *82             * @since 4.0.083             *84             * @param int $element_limit Default elements limit.85             */86            $element_limit = apply_filters( 'xmlrpc_element_limit', $element_limit );87        }88        if ( $element_limit && 2 * $element_limit < substr_count( $this->message, '<' ) ) {89            return false;90        }91 92        $this->_parser = xml_parser_create();93        // Set XML parser to take the case of tags in to account94        xml_parser_set_option($this->_parser, XML_OPTION_CASE_FOLDING, false);95        // Set XML parser callback functions96        xml_set_element_handler($this->_parser, array($this, 'tag_open'), array($this, 'tag_close'));97        xml_set_character_data_handler($this->_parser, array($this, 'cdata'));98 99        // 256Kb, parse in chunks to avoid the RAM usage on very large messages100        $chunk_size = 262144;101 102        /**103         * Filters the chunk size that can be used to parse an XML-RPC response message.104         *105         * @since 4.4.0106         *107         * @param int $chunk_size Chunk size to parse in bytes.108         */109        $chunk_size = apply_filters( 'xmlrpc_chunk_parsing_size', $chunk_size );110 111        $final = false;112 113        do {114            if (strlen($this->message) <= $chunk_size) {115                $final = true;116            }117 118            $part = substr($this->message, 0, $chunk_size);119            $this->message = substr($this->message, $chunk_size);120 121            if (!xml_parse($this->_parser, $part, $final)) {122                if (PHP_VERSION_ID < 80000) { // xml_parser_free() has no effect as of PHP 8.0.123                    xml_parser_free($this->_parser);124                }

Changelog

Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/IXR/class-IXR-message.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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