I’m kinda loving on WordPress MU. One of my recent projects required building web sites that pulled from a shared database. WordPress MU allowed me to create a one-button website builder for my client. WordPress MU calls them blogs, but my client will map a unique domain to each blog, and, well, doesn’t use them as blogs at all. So I’m calling them sites here.

By filling in three fields and clicking a button, my client creates a website that

• Associates metadata with the site that specifies filter criteria to select records from the shared database
• Sets the permalink structure for the new site to a custom setting
• Creates a key category for the new site, one that is used for the posts generated in a later step
• Sets the theme
• All the initial pages are created, including content. The “slug” is set specifically to support the URL structure we want. Page template is also set here because our design calls for a hierarchy of pages.
• If the PageMash plugin is active (it is auto-activated for all new blogs using Plugin Commander), certain pages are hidden, and a specific order is set so that page navigation comes out looking good
• The front page is set, because we are creating CMS sites, not blogs
• Several hundred posts are generated out of the underlying shared non-WPMU database tables

All of this takes something like 20 seconds, at which point the admin can visit the new site as a subdomain.  The theme has been applied, navigation works correctly, it is beauty.

Here’s how it is done in code.  All you need to do is register a function for the action hook that WordPress MU runs when a new blog is created.

function mypp_initialize_blog($blog_id) {
  global $wp_rewrite;
 
  // first, switch to the new blog; we will undo this at the
  // end of the function with restore_current_blog()
  switch_to_blog($blog_id);
  // add a blog option, here a filter with a default value
  add_option($blog_id, 'campus_selection_criteria', "CampusStateID='CA'");
  // Set a custom permalink structure
  $wp_rewrite->set_permalink_structure('/%category%/%postname%');
  $wp_rewrite->flush_rules();
  if (function_exists('wp_create_category')) {
      wp_create_category('schools');
  }
 
  // switch theme - this one specifies a child theme
  switch_theme('corporate', 'tweaked-corporate');
  // Prepare options used by the pageMash plugin, auto-activated for new sites
  if(!is_array(get_option('exclude_pages')))
    $excludePagesList=array();
  else
    $excludePagesList = get_option('exclude_pages'); //if it's empty set as an empty array
  // add pages to support the basic page structure
  // NOTE: the full code is not shown, standard use of wp_insert post
  // for each page:
  $newid = wp_insert_post($postdata);
  if ($newid && !is_wp_error($newid)) {
    add_meta($newid);
    if ( IWANTOEXCLUDETHISPARTICULARPAGEFROMNAVIGATION )
      $excludePagesList[] = $newid;
    if (THISPARTICULARPAGE == 'home') {
      update_option('show_on_front', 'page');
      update_option('page_on_front', $newid);
    }
  } else {
    // error handling if insert post failed
  }
  // end for each page
  update_option('exclude_pages', $excludePagesList);
  // now generate posts for schools from the shared database
  createSchoolAsPost('', $blog_id);
  // we're done! restore our initial blog
  restore_current_blog();
} // function mypp_initialize_blog
 
add_action('wpmu_new_blog', 'mypp_initialize_blog');

OK, this one is obscure. I only post about what I can’t find on Google!

Until recently it has been possible to run command-line PHP scripts that include wp-config.php or wpmu-settings.php, in order to give those scripts access to WordPress globals like $wpdb, functions such as wp_insert_post etc.

These scripts worked with WordPress-MU until recently — now the scripts just exit with no output.

The reason? WPMU now initiates a redirect in the bootstrap process (search for ‘header( “Location: “‘ in wpmu-settings.php). A browser can follow that redirection, but a command line script cannot. So, if you want to initiate scripts that run from the command line, you will have to get the web server involved by invoking a text browser such as curl, wget, or links.

It’s best not to force your scripts to figure out where to find wp-config.php anyway. I have taken to using a method suggested in this thread, as shown in the code sample below. The good news is, you know that your script will work the same whether initiated from a plugin in a graphic browser, used in an Ajax call, or initiated from cron or the command line shell.

So instead of kicking your script off with something like

/usr/bin/php -q myscript.php

You will create the script as a proper plugin and do something like

/usr/bin/curl -d mypp_cmd=status http://mywpmusite.com

Sample plugin code used for the above example follows. The prefix for the functions is ‘mypp’, which of course stands for ‘MY Plugin Prefix’ to create a unique namespace. The code below returns results as JSON encoded, and calls die()/exit() at the end to prevent an entire page being created. For log files run from cron, you may choose to return plain text instead.

  /**
   * Add a query var for this plugin
   * This allows Ajax programs to operate without requiring file paths
   * Instead, Ajax functions look for the query var 'mypp_cmd'
   */
  function mypp_query_vars($qvars) {
    $qvars[] = 'mypp_cmd';
    return $qvars;
  } // function mypp_query_vars
 
  /**
   * Handle AJAX requests in the template_redirect action
   * We recognize our requests from the query var 'mypp_cmd'
   * Here we allow GET requests using $_REQUEST; to restrict to POST, use $_POST instead
   */
  function mypp_template_redirect() {
    global $wpdb;
    $cmd = get_query_var('mypp_cmd');
    $response = array();
    if ($cmd) {
      switch($cmd) {
      case 'status':
	$response['status'] = array('success' => true,
				    'message' => 'Sample status message');
	break;
      default:
	$response['status'] = array('success' => false,
				    'msg' => 'Unknown command',
				    'cmd' => $cmd);
	break;
      } // switch $cmd
      header('Content-type: text/x-json; charset=utf-8');
      print utf8_encode(json_encode($response));
      die();
    } // $cmd is set
  } // function mypp_template_redirect
 
add_filter('query_vars', array($this, 'mypp_query_vars'));
add_action('template_redirect', array($this, 'mypp_template_redirect'));