get_transient( string $transient )
Get the value of a transient.
Description Description
If the transient does not exist, does not have a value, or has expired, then the return value will be false.
Parameters Parameters
- $transient
-
(string) (Required) Transient name. Expected to not be SQL-escaped.
Return Return
(mixed) Value of transient.
Source Source
File: wp-includes/option.php
function get_transient( $transient ) {
/**
* Filters the value of an existing transient.
*
* The dynamic portion of the hook name, `$transient`, refers to the transient name.
*
* Passing a truthy value to the filter will effectively short-circuit retrieval
* of the transient, returning the passed value instead.
*
* @since 2.8.0
* @since 4.4.0 The `$transient` parameter was added
*
* @param mixed $pre_transient The default value to return if the transient does not exist.
* Any value other than false will short-circuit the retrieval
* of the transient, and return the returned value.
* @param string $transient Transient name.
*/
$pre = apply_filters( "pre_transient_{$transient}", false, $transient );
if ( false !== $pre ) {
return $pre;
}
if ( wp_using_ext_object_cache() ) {
$value = wp_cache_get( $transient, 'transient' );
} else {
$transient_option = '_transient_' . $transient;
if ( ! wp_installing() ) {
// If option is not in alloptions, it is not autoloaded and thus has a timeout
$alloptions = wp_load_alloptions();
if ( ! isset( $alloptions[ $transient_option ] ) ) {
$transient_timeout = '_transient_timeout_' . $transient;
$timeout = get_option( $transient_timeout );
if ( false !== $timeout && $timeout < time() ) {
delete_option( $transient_option );
delete_option( $transient_timeout );
$value = false;
}
}
}
if ( ! isset( $value ) ) {
$value = get_option( $transient_option );
}
}
/**
* Filters an existing transient's value.
*
* The dynamic portion of the hook name, `$transient`, refers to the transient name.
*
* @since 2.8.0
* @since 4.4.0 The `$transient` parameter was added
*
* @param mixed $value Value of transient.
* @param string $transient Transient name.
*/
return apply_filters( "transient_{$transient}", $value, $transient );
}
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Changelog Changelog
| Version | Description |
|---|---|
| 2.8.0 | Introduced. |
User Contributed Notes User Contributed Notes
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Example of using
get_transient,set_transientandWP_Query// Get any existing copy of our transient data if ( false === ( $special_query_results = get_transient( 'special_query_results' ) ) ) { // It wasn't there, so regenerate the data and save the transient $special_query_results = new WP_Query( 'cat=5&order=random&tag=tech&post_meta_key=thumbnail' ); set_transient( 'special_query_results', $special_query_results ); } // Use the data like you would have normally...Add
WP_DEBUGin the conditional statement if you always want live data during development stage<?php if ( WP_DEBUG or false === ( $special_query_results = get_transient( 'special_query_results' ) ) ) ) { // It wasn't there, so regenerate the data and save the transient $special_query_results = new WP_Query( 'cat=5&order=random&tag=tech&post_meta_key=thumbnail' ); set_transient( 'special_query_results', $special_query_results ); } ?>Useful to know: If the transient exists but has expired, the return value will not just be false. The expired transient will be deleted at the same time.
WordPress does not delete expired transients on its own, but using get_transient() on an expired one will do so. Non-expired transients, or transients without expiration will only be deleted with delete_transient().