set_transient() - WordPress 函数参考中文文档

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set_transient()

发布于 2017-09-11 字数7760 浏览 843 评论 0

set_transient( string $transient,  mixed $value,  int $expiration )

Set/update the value of a transient.


描述

You do not need to serialize values. If the value needs to be serialized, then it will be serialized before it is set.


参数

$transient

(string)
(Required)
Transient name. Expected to not be SQL-escaped. Must be 172 characters or fewer in length.

$value

(mixed)
(Required)
Transient value. Must be serializable if non-scalar. Expected to not be SQL-escaped.

$expiration

(int)
(Optional)
Time until expiration in seconds. Default 0 (no expiration).


返回值

(bool) False if value was not set and true if value was set.


源代码

File: wp-includes/option.php

function set_transient( $transient, $value, $expiration = 0 ) {

	$expiration = (int) $expiration;

	/**
	 * Filters a specific transient before its value is set.
	 *
	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
	 *
	 * @since 3.0.0
	 * @since 4.2.0 The `$expiration` parameter was added.
	 * @since 4.4.0 The `$transient` parameter was added.
	 *
	 * @param mixed  $value      New value of transient.
	 * @param int    $expiration Time until expiration in seconds.
	 * @param string $transient  Transient name.
	 */
	$value = apply_filters( "pre_set_transient_{$transient}", $value, $expiration, $transient );

	/**
	 * Filters the expiration for a transient before its value is set.
	 *
	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
	 *
	 * @since 4.4.0
	 *
	 * @param int    $expiration Time until expiration in seconds. Use 0 for no expiration.
	 * @param mixed  $value      New value of transient.
	 * @param string $transient  Transient name.
	 */
	$expiration = apply_filters( "expiration_of_transient_{$transient}", $expiration, $value, $transient );

	if ( wp_using_ext_object_cache() ) {
		$result = wp_cache_set( $transient, $value, 'transient', $expiration );
	} else {
		$transient_timeout = '_transient_timeout_' . $transient;
		$transient_option = '_transient_' . $transient;
		if ( false === get_option( $transient_option ) ) {
			$autoload = 'yes';
			if ( $expiration ) {
				$autoload = 'no';
				add_option( $transient_timeout, time() + $expiration, '', 'no' );
			}
			$result = add_option( $transient_option, $value, '', $autoload );
		} else {
			// If expiration is requested, but the transient has no timeout option,
			// delete, then re-create transient rather than update.
			$update = true;
			if ( $expiration ) {
				if ( false === get_option( $transient_timeout ) ) {
					delete_option( $transient_option );
					add_option( $transient_timeout, time() + $expiration, '', 'no' );
					$result = add_option( $transient_option, $value, '', 'no' );
					$update = false;
				} else {
					update_option( $transient_timeout, time() + $expiration );
				}
			}
			if ( $update ) {
				$result = update_option( $transient_option, $value );
			}
		}
	}

	if ( $result ) {

		/**
		 * Fires after the value for a specific transient has been set.
		 *
		 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
		 *
		 * @since 3.0.0
		 * @since 3.6.0 The `$value` and `$expiration` parameters were added.
		 * @since 4.4.0 The `$transient` parameter was added.
		 *
		 * @param mixed  $value      Transient value.
		 * @param int    $expiration Time until expiration in seconds.
		 * @param string $transient  The name of the transient.
		 */
		do_action( "set_transient_{$transient}", $value, $expiration, $transient );

		/**
		 * Fires after the value for a transient has been set.
		 *
		 * @since 3.0.0
		 * @since 3.6.0 The `$value` and `$expiration` parameters were added.
		 *
		 * @param string $transient  The name of the transient.
		 * @param mixed  $value      Transient value.
		 * @param int    $expiration Time until expiration in seconds.
		 */
		do_action( 'setted_transient', $transient, $value, $expiration );
	}
	return $result;
}

更新日志

Version 描述
2.8.0 Introduced.

相关函数

Uses

  • wp-includes/option.php:
    expiration_of_transient_{$transient}
  • wp-includes/cache.php:
    wp_cache_set()
  • wp-includes/load.php:
    wp_using_ext_object_cache()
  • wp-includes/plugin.php:
    apply_filters()
  • wp-includes/plugin.php:
    do_action()
  • wp-includes/option.php:
    pre_set_transient_{$transient}
  • wp-includes/option.php:
    set_transient_{$transient}
  • wp-includes/option.php:
    setted_transient
  • wp-includes/option.php:
    add_option()
  • wp-includes/option.php:
    delete_option()
  • wp-includes/option.php:
    update_option()
  • wp-includes/option.php:
    get_option()
  • Show 7 more uses
    Hide more uses


Used By

  • wp-includes/class-wp-oembed-controller.php:
    WP_oEmbed_Controller::get_proxy_item()
  • wp-admin/includes/class-wp-plugins-list-table.php:
    WP_Plugins_List_Table::prepare_items()
  • wp-admin/includes/theme-install.php:
    install_themes_feature_list()
  • wp-admin/includes/dashboard.php:
    wp_dashboard_cached_rss_widget()
  • wp-admin/includes/deprecated.php:
    wp_dashboard_plugins_output()
  • wp-includes/cron.php:
    spawn_cron()
  • wp-includes/pluggable.php:
    wp_rand()
  • wp-includes/class-wp-feed-cache-transient.php:
    WP_Feed_Cache_Transient::save()
  • wp-includes/class-wp-feed-cache-transient.php:
    WP_Feed_Cache_Transient::touch()
  • wp-includes/media.php:
    wp_maybe_generate_attachment_metadata()
  • wp-includes/ms-functions.php:
    get_dirsize()
  • wp-includes/author-template.php:
    is_multi_author()
  • wp-includes/rss.php:
    RSSCache::set()
  • Show 8 more used by
    Hide more used by


User Contributed Notes

  1. Skip to note content

    You must log in to vote on the helpfulness of this noteVote results for this note: 0You must log in to vote on the helpfulness of this note

    Contributed by Nicola Mustone

    This example shows how to set a transient with the latest five blog posts. It expires after one day.
    It uses time constants to set the expiration time.

    
    // Set the arguments for the custom query
    $args = array(
        'post_type'      => 'post',
        'posts_per_page' => 5,
        'orderby'        => 'date',
        'order'          => 'DESC'
    );
    $latest_post = new WP_Query( $args );
    
    // Save the results in a transient named latest_5_posts
    set_transient( 'latest_5_posts', $latest_post, DAY_IN_SECONDS );
    

    To know more about how to get posts and custom post type items read the documentation of WP_Query.

  2. Saving the $special_query_results object for 12 hours

    
    set_transient( 'special_query_results', $special_query_results, 12 * HOUR_IN_SECONDS );
    

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