Title: WP_oEmbed::discover
Published: April 25, 2014
Last modified: May 20, 2026
---
# WP_oEmbed::discover( string $url ): string|false
## In this article
* [Parameters](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#parameters)
* [Return](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#return)
* [Source](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#source)
* [Hooks](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#hooks)
* [Related](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#related)
* [Changelog](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#changelog)
[ Back to top](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#wp--skip-link--target)
Attempts to discover link tags at the given URL for an oEmbed provider.
## [Parameters](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#parameters)
`$url`stringrequired
The URL that should be inspected for discovery `` tags.
## [Return](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#return)
string|false The oEmbed provider URL on success, false on failure.
## [Source](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#source)
```php
public function discover( $url ) {
$providers = array();
$args = array(
'limit_response_size' => 153600, // 150 KB
);
/**
* Filters oEmbed remote get arguments.
*
* @since 4.0.0
*
* @see WP_Http::request()
*
* @param array $args oEmbed remote get arguments.
* @param string $url URL to be inspected.
*/
$args = apply_filters( 'oembed_remote_get_args', $args, $url );
// Fetch URL content.
$request = wp_safe_remote_get( $url, $args );
$html = wp_remote_retrieve_body( $request );
if ( $html ) {
/**
* Filters the link types that contain oEmbed provider URLs.
*
* @since 2.9.0
*
* @param string[] $format Array of oEmbed link types. Accepts 'application/json+oembed',
* 'text/xml+oembed', and 'application/xml+oembed' (incorrect,
* used by at least Vimeo).
*/
$linktypes = apply_filters(
'oembed_linktypes',
array(
'application/json+oembed' => 'json',
'text/xml+oembed' => 'xml',
'application/xml+oembed' => 'xml',
)
);
// Strip .
$html_head_end = stripos( $html, '' );
if ( $html_head_end ) {
$html = substr( $html, 0, $html_head_end );
}
// Do a quick check.
$tagfound = false;
foreach ( $linktypes as $linktype => $format ) {
if ( stripos( $html, $linktype ) ) {
$tagfound = true;
break;
}
}
if ( $tagfound && preg_match_all( '#]+)/?>#iU', $html, $links ) ) {
foreach ( $links[1] as $link ) {
$atts = shortcode_parse_atts( $link );
if ( ! empty( $atts['type'] ) && ! empty( $linktypes[ $atts['type'] ] ) && ! empty( $atts['href'] ) ) {
$providers[ $linktypes[ $atts['type'] ] ] = htmlspecialchars_decode( $atts['href'] );
// Stop here if it's JSON (that's all we need).
if ( 'json' === $linktypes[ $atts['type'] ] ) {
break;
}
}
}
}
}
// JSON is preferred to XML.
if ( ! empty( $providers['json'] ) ) {
return $providers['json'];
} elseif ( ! empty( $providers['xml'] ) ) {
return $providers['xml'];
} else {
return false;
}
}
```
[View all references](https://developer.wordpress.org/reference/files/wp-includes/class-wp-oembed.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/class-wp-oembed.php#L435)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/class-wp-oembed.php#L435-L515)
## [Hooks](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#hooks)
[apply_filters( ‘oembed_linktypes’, string[] $format )](https://developer.wordpress.org/reference/hooks/oembed_linktypes/)
Filters the link types that contain oEmbed provider URLs.
[apply_filters( ‘oembed_remote_get_args’, array $args, string $url )](https://developer.wordpress.org/reference/hooks/oembed_remote_get_args/)
Filters oEmbed remote get arguments.
## [Related](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#related)
| Uses | Description |
| [stripos()](https://developer.wordpress.org/reference/functions/stripos/)`wp-includes/class-pop3.php` | |
| [wp_safe_remote_get()](https://developer.wordpress.org/reference/functions/wp_safe_remote_get/)`wp-includes/http.php` |
Retrieves the raw response from a safe HTTP request using the GET method.
|
| [wp_remote_retrieve_body()](https://developer.wordpress.org/reference/functions/wp_remote_retrieve_body/)`wp-includes/http.php` |
Retrieves only the body from the raw response.
|
| [shortcode_parse_atts()](https://developer.wordpress.org/reference/functions/shortcode_parse_atts/)`wp-includes/shortcodes.php` |
Retrieves all attributes from the shortcodes tag.
|
| [apply_filters()](https://developer.wordpress.org/reference/functions/apply_filters/)`wp-includes/plugin.php` |
Calls the callback functions that have been added to a filter hook.
|
[Show 1 more](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#)
[Show less](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#)
| Used by | Description |
| [WP_oEmbed::get_provider()](https://developer.wordpress.org/reference/classes/wp_oembed/get_provider/)`wp-includes/class-wp-oembed.php` |
Takes a URL and returns the corresponding oEmbed provider’s URL, if there is one.
|
## [Changelog](https://developer.wordpress.org/reference/classes/WP_oEmbed/discover/?output_format=md#changelog)
| Version | Description |
| [2.9.0](https://developer.wordpress.org/reference/since/2.9.0/) | Introduced. |
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