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WordPress

WP_HTML_Processor::serialize(): string|null

Since
6.7.0
Source
wp-includes/html-api/class-wp-html-processor.php:1316
Returns normalized HTML for a fragment by serializing it.

Description

This differs from WP_HTML_Processor::normalize in that it starts with a specific HTML Processor, which must not have already started scanning; it must be in the initial ready state and will be in the completed state once serialization is complete.

Many aspects of an input HTML fragment may be changed during normalization.

  • Attribute values will be double-quoted.
  • Duplicate attributes will be removed.
  • Omitted tags will be added.
  • Tag and attribute name casing will be lower-cased, except for specific SVG and MathML tags or attributes.
  • Text will be re-encoded, null bytes handled, and invalid UTF-8 replaced with U+FFFD.
  • Any incomplete syntax trailing at the end will be omitted, for example, an unclosed comment opener will be removed.

Example:

$processor = WP_HTML_Processor::create_fragment( '<a href=#anchor v=5 href="/" enabled>One</a another v=5><!--' );
echo $processor->serialize();
// <a href="#anchor" v="5" enabled>One</a>

$processor = WP_HTML_Processor::create_fragment( '<div></p>fun<table><td>cell</div>' );
echo $processor->serialize();
// <div><p></p>fun<table><tbody><tr><td>cell</td></tr></tbody></table></div>

$processor = WP_HTML_Processor::create_fragment( '<![CDATA[invalid comment]]> syntax < <> "oddities"' );
echo $processor->serialize();
// <!--[CDATA[invalid comment]]--> syntax &lt; &lt;&gt; &quot;oddities&quot;

Compatibility

WordPress
since 6.7.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

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

Return value

string|null
Normalized HTML markup represented by processor, or null if unable to generate serialization.

Performance profile

How much work a call to WP_HTML_Processor::serialize() 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
10–24

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 34.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

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

What it touches

  • hookthird-party callbacksdo_action()one call below WP_HTML_Processor::serialize()

What one call costs · 3 distinct outcomes

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

WhenInstructionsCalls it makes
always10wp_trigger_error()
!->next_token()14->next_token(), ->get_last_error()
!->next_token()24->next_token(), ->get_last_error(), ->get_last_error(), wp_trigger_error()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 34 instructions, 10–24 executed per call, 3 branches. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 4

Source code

View on Trac View on GitHub 

	public function serialize(): ?string {		if ( WP_HTML_Tag_Processor::STATE_READY !== $this->parser_state ) {			wp_trigger_error(				__METHOD__,				'An HTML Processor which has already started processing cannot serialize its contents. Serialize immediately after creating the instance.',				E_USER_WARNING			);			return null;		} 		$html = '';		while ( $this->next_token() ) {			$html .= $this->serialize_token();		} 		if ( null !== $this->get_last_error() ) {			wp_trigger_error(				__METHOD__,				"Cannot serialize HTML Processor with parsing error: {$this->get_last_error()}.",				E_USER_WARNING			);			return null;		} 		return $html;	}

Changelog

Introduced in 6.7.0. 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/html-api/class-wp-html-processor.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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