is_serialized( string $data, bool $strict = true ): bool
- Since
- 2.0.5, 6.1.0
- Source
wp-includes/functions.php:674
Description
If $data is not a string, then returned value will always be false.
Serialized data is always a string.
Compatibility
- WordPress
- since 6.1.0
- 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.
Parameters
$datastring- Value to check to see if was serialized.
$strictbooloptional- Whether to be strict about the end of the string. Default true.Default:
true
Return value
bool- False if not serialized and true if it was.
Performance profile
How much work a call to is_serialized() 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
- Trivial
- Scaling
- Constant
- Instructions
- 5–57
- Plugin surface
- None
- Called by
- 5
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 88.
Nothing here hands control to plugin code.
5 places in core call this, so the cost is paid more often than your own code shows.
What one call costs · 1 distinct outcome
One number would be a lie: the work depends on which branch runs. These are every distinct cost is_serialized() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 5–57 | none |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 88 | 5–57 | 25 | |
| 8.5 | 88 | 5–57 | 25 | |
| 8.4 | 88 | 5–57 | 25 | 24 fewer instructions than PHP 8.3 |
| 8.3 | 112 | 5–68 | 25 | |
| 8.2 | 112 | 5–68 | 25 | |
| 8.1 | 112 | 5–68 | 25 | 1 more instruction than PHP 7.4 |
| 7.4 | 111 | 5–70 | 25 |
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 · 1
- str_contains()Polyfill for `str_contains()` function added in PHP 8.0.
Used by · 5
- WP_Customize_Manager::import_theme_starter_content()Imports theme starter content into the customized state.
- _list_meta_row()Outputs a single row of public meta data in the Custom Fields meta box.
- maybe_serialize()Serializes data, if needed.
- maybe_unserialize()Unserializes data only if it was serialized.
- wp_targeted_link_rel()Adds `rel="noopener"` to all HTML A elements that have a target.
Source code
function is_serialized( $data, $strict = true ) { // If it isn't a string, it isn't serialized. if ( ! is_string( $data ) ) { return false; } $data = trim( $data ); if ( 'N;' === $data ) { return true; } if ( strlen( $data ) < 4 ) { return false; } if ( ':' !== $data[1] ) { return false; } if ( $strict ) { $lastc = substr( $data, -1 ); if ( ';' !== $lastc && '}' !== $lastc ) { return false; } } else { $semicolon = strpos( $data, ';' ); $brace = strpos( $data, '}' ); // Either ; or } must exist. if ( false === $semicolon && false === $brace ) { return false; } // But neither must be in the first X characters. if ( false !== $semicolon && $semicolon < 3 ) { return false; } if ( false !== $brace && $brace < 4 ) { return false; } } $token = $data[0]; switch ( $token ) { case 's': if ( $strict ) { if ( '"' !== substr( $data, -2, 1 ) ) { return false; } } elseif ( ! str_contains( $data, '"' ) ) { return false; } // Or else fall through. case 'a': case 'O': case 'E': return (bool) preg_match( "/^{$token}:[0-9]+:/s", $data ); case 'b': case 'i': case 'd': $end = $strict ? '$' : ''; return (bool) preg_match( "/^{$token}:[0-9.E+-]+;$end/", $data ); } return false;}Changelog
Introduced in 2.0.5. Unchanged from 6.7.7 through 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/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
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