switch_to_blog

Switch the current blog.

Description

switch_to_blog( (int) $new_blog, (null) $deprecated = null ); 

This function is useful if you need to pull posts, or other information, from other blogs. You can switch back afterwards using restore_current_blog(…).

Things that aren't switched: - autoloaded options. See #14992 - plugins. See #14941

Parameters (2)

0. $new_blog (int)
The id of the blog you want to switch to. Default: current blog
1. $deprecated — Optional. (null) => null
Deprecated argument

Usage

  1. if ( !function_exists( 'switch_to_blog' ) ) { 
  2.     require_once ABSPATH . WPINC . '/ms-blogs.php'; 
  3. } 
  4.   
  5. // The id of the blog you want to switch to. Default: current blog 
  6. $new_blog = -1; 
  7.   
  8. // Deprecated argument 
  9. $deprecated = null; 
  10.   
  11. // NOTICE! Understand what this does before running. 
  12. $result = switch_to_blog($new_blog, $deprecated); 
  13.     

Defined (1)

The function is defined in the following location(s).

/wp-includes/ms-blogs.php  
  1. function switch_to_blog( $new_blog, $deprecated = null ) { 
  2.     global $wpdb, $wp_roles; 
  3.  
  4.     $blog_id = get_current_blog_id(); 
  5.     if ( empty( $new_blog ) ) { 
  6.         $new_blog = $blog_id; 
  7.     } 
  8.  
  9.     $GLOBALS['_wp_switched_stack'][] = $blog_id; 
  10.  
  11.     /** 
  12.      * If we're switching to the same blog id that we're on,  
  13.      * set the right vars, do the associated actions, but skip 
  14.      * the extra unnecessary work 
  15.      */ 
  16.     if ( $new_blog == $blog_id ) { 
  17.         /** 
  18.          * Fires when the blog is switched. 
  19.          * 
  20.          * @since MU 
  21.          * 
  22.          * @param int $new_blog New blog ID. 
  23.          * @param int $new_blog Blog ID. 
  24.          */ 
  25.         do_action( 'switch_blog', $new_blog, $new_blog ); 
  26.         $GLOBALS['switched'] = true; 
  27.         return true; 
  28.     } 
  29.  
  30.     $wpdb->set_blog_id( $new_blog ); 
  31.     $GLOBALS['table_prefix'] = $wpdb->get_blog_prefix(); 
  32.     $prev_blog_id = $blog_id; 
  33.     $GLOBALS['blog_id'] = $new_blog; 
  34.  
  35.     if ( function_exists( 'wp_cache_switch_to_blog' ) ) { 
  36.         wp_cache_switch_to_blog( $new_blog ); 
  37.     } else { 
  38.         global $wp_object_cache; 
  39.  
  40.         if ( is_object( $wp_object_cache ) && isset( $wp_object_cache->global_groups ) ) { 
  41.             $global_groups = $wp_object_cache->global_groups; 
  42.         } else { 
  43.             $global_groups = false; 
  44.         } 
  46.  
  47.         if ( function_exists( 'wp_cache_add_global_groups' ) ) { 
  48.             if ( is_array( $global_groups ) ) { 
  49.                 wp_cache_add_global_groups( $global_groups ); 
  50.             } else { 
  51.                 wp_cache_add_global_groups( array( 'users', 'userlogins', 'usermeta', 'user_meta', 'useremail', 'userslugs', 'site-transient', 'site-options', 'site-lookup', 'blog-lookup', 'blog-details', 'rss', 'global-posts', 'blog-id-cache', 'networks', 'sites', 'site-details' ) ); 
  52.             } 
  53.             wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) ); 
  54.         } 
  55.     } 
  56.  
  57.     if ( did_action( 'init' ) ) { 
  58.         $wp_roles = new WP_Roles(); 
  59.         $current_user = wp_get_current_user(); 
  60.         $current_user->for_blog( $new_blog ); 
  61.     } 
  62.  
  63.     /** This filter is documented in wp-includes/ms-blogs.php */ 
  64.     do_action( 'switch_blog', $new_blog, $prev_blog_id ); 
  65.     $GLOBALS['switched'] = true; 
  66.  
  67.     return true; 
  68. }