wp_check_invalid_utf8( string $text, bool $strip = false ): string
- Since
- 2.8.0
- Source
wp-includes/formatting.php:1095
Compatibility
- WordPress
- since 2.8.0
- 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
$textstring- The text which is to be checked.
$stripbooloptional- Whether to attempt to strip out invalid UTF8. Default false.Default:
false
Return value
string- The checked text.
Performance profile
How much work a call to wp_check_invalid_utf8() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Moderate
- Scaling
- Constant
- Instructions
- 8–34
- Plugin surface
- None
- Called by
- 6
Reads stored settings via get_option(), cached per request but not free on a cold cache.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 39.
Nothing here hands control to plugin code.
6 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- optionoption read or write
get_option()one call below wp_check_invalid_utf8()
Further down the call graph this can also reach hook, cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_check_invalid_utf8() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 8–26 | none |
!isset($is_utf8) | 15–29 | is_utf8_charset() |
isset($is_utf8) | 27–31 | iconv() |
!isset($is_utf8) | 30–34 | is_utf8_charset(), iconv() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 39 | 8–34 | 7 | |
| 8.5 | 39 | 8–34 | 7 | |
| 8.4 | 39 | 8–34 | 7 | 6 fewer instructions than PHP 8.3 |
| 8.3 | 45 | 8–40 | 7 | |
| 8.2 | 45 | 8–40 | 7 | |
| 8.1 | 45 | 8–40 | 7 | |
| 7.4 | 45 | 8–40 | 7 |
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
- is_utf8_charset()Indicates if a given slug for a character set represents the UTF-8 text encoding. If not provided, examines the current blog's charset.
Used by · 6
- _sanitize_text_fields()Internal helper function to sanitize a string from user input or from the database.
- _wp_json_convert_string()Converts a string to UTF-8, so that it can be safely encoded to JSON.
- esc_attr()Escaping for HTML attributes.
- esc_html()Escaping for HTML blocks.
- esc_js()Escapes single quotes, `"`, ``, `&`, and fixes line endings.
- esc_xml()Escaping for XML blocks.
Source code
function wp_check_invalid_utf8( $text, $strip = false ) { $text = (string) $text; if ( 0 === strlen( $text ) ) { return ''; } // Store the site charset as a static to avoid multiple calls to get_option(). static $is_utf8 = null; if ( ! isset( $is_utf8 ) ) { $is_utf8 = is_utf8_charset(); } if ( ! $is_utf8 ) { return $text; } // Check for support for utf8 in the installed PCRE library once and store the result in a static. static $utf8_pcre = null; if ( ! isset( $utf8_pcre ) ) { // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged $utf8_pcre = @preg_match( '/^./u', 'a' ); } // We can't demand utf8 in the PCRE installation, so just return the string in those cases. if ( ! $utf8_pcre ) { return $text; } // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- preg_match fails when it encounters invalid UTF8 in $text. if ( 1 === @preg_match( '/^./us', $text ) ) { return $text; } // Attempt to strip the bad chars if requested (not recommended). if ( $strip && function_exists( 'iconv' ) ) { return iconv( 'utf-8', 'utf-8', $text ); } return '';}Changelog
Introduced in 2.8.0. 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 6.8.8 tag, from
src/wp-includes/formatting.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.