switch_to_blog( int $new_blog_id, bool $deprecated = null ): true

User Contributed Notes

1. Skip to note 7 content

   Codex 9 years ago

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   Multiple switches

   foreach( $blog_ids as $blog_id ){
       switch_to_blog( $blog_id );
       //Do stuff
       restore_current_blog();
   }

   If you do not call restore_current_blog() after every switch_to_blog() , WordPress can get into a state that can potentially build the wrong urls for the site. See restore_current_blog() vs switch_to_blog() .
2. Skip to note 8 content

   Brent Leavitt 6 years ago

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   I was a little confused with the switch_to_blog() functionality when I first started using it. This function only affects the database which is being accessed on the network. I cannot access blocks of code, classes, functions, or variables that exist within a specific blog on the network. By extension, this also means that I cannot access themes or plugins that only exist on one site on the network. I was hoping for a little more power with this function before I realized that this was limited to site data being stored in the database.

   The following example does not work:

   Site 1 --> Site1_only_plugin --> Site1_only_plugin_function()

   That is, Site 1 has a unique plugin that has a bit of functionality that I want to access on Site 2 (or anywhere else on the network) without loading the full plugin to Site 2. I might be tempted to do something like this from Site 2:

   switch_to_blog( $site1 );
   
   $var = site1_only_plugin_function();
   
   restore_current_blog();

   This does not work. I can only use the switch_to_blog() functionality to access database values from other sites on the network. Here’s an example that does work:

   Site 1 --> Site1_only_plugin --> Site1_only_plugin_function()--> add_option( 'Site1_only_plugin_option', $var )

   The plugin on Site 1 has first set a value in the Site 1 database. I can then access that value in the options table from anywhere on the network as follows:

   switch_to_blog( $site1 );
   
   $var = get_option( 'Site1_only_plugin_option' );
   
   restore_current_blog();
3. Skip to note 9 content

   Codex 9 years ago

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   One switch

   switch_to_blog( $blog_id );
   // Do something
   restore_current_blog();
4. Skip to note 10 content

   Lance Cleveland 9 years ago

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   Description

   Restores previous blog after a switch_to_blog call.

   Contrary to the function’s name, this does NOT restore the original blog but the previous blog. Calling `switch_to_blog() ` twice in a row and then calling this function will result in being on the blog set by the first `switch_to_blog() ` call.

   • Looks like this comment was meant for the `restore_current_blog() ` function, not on this page.

     jakeparis 2 years ago
5. Skip to note 11 content

   dekket 4 years ago

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   When using switch_to_blog() outside of WordPress, you need to have the global $switched defined. The variable for defining which blog ID to target, may also not be $blog_id, because it is used by WP Core.

   The below example will not create a post within the correct blog_id, unless $switched is defined.

   <?php
   require_once '../wp-load.php';
   global $switched;
   $blog_id_target = 2;
   switch_to_blog( $blog_id_target );
   
   // Create a post programmatically, for blog 2.
   $id = wp_insert_post(
   	array(
   		'post_author'   => 1,
   		'post_status'   => 'publish',
   		'post_type'     => 'custom_post_type',
   		'post_content'  => 'Post body here',
   		'post_title'    => 'Post title here'
   	)
   );
   ?>
6. Skip to note 12 content

   jakeparis 2 years ago

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   It’s important to note that switch_to_blog() does not check whether a blog actually exists for the supplied ID. You could potentially switch to a non-existant blog and run queries against non-existant tables.