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In a new project we are using wp-super-cache (the client's preferred plugin) to create the static html files for custom content types. But we are trying to figure out if everything is being cached properly.

This is a 2 part question.

1) The theme we have created utilizes page templates to output json that is ingested via ajax calls. ie. if you hit the page: theurl.com/sample - you will get pure json. While there is a non-javascript version of every page and post, Ajax drives the front end of this theme. We have removed the header and footer in these files so that it is pure json, and we are trying to figure out how to determine if the json is being cached. In theory the data would be cached because it is technically a page served up by wordpress. But, how can we figure out if it is being cached?

2) We are using the json api plugin to serve up certain post data as well. http://wordpress.org/extend/plugins/json-api/ For this example, let's say we are utilizing the plugin's default method of output and hitting this page: my url.com/category/news?json=1 - Does anyone know how we can verify if this output is being cached? If it isn't being cached, what method would make this happen?

There doesn't seem to be much information about this online, so in the spirit of creating compelling and optimized wordpress sites, help a brother out

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2 Answers 2

WP Super Cache examines your WordPress site's pages for some HTML tags before it caches them.

Your pages most probably don't have </html> tag (common issue), in that case, try adding something like //</html> -- that's a workaround, and WP Super Cache should then generate cached versions of your pages.

Why does WP Super Cache do it like that? See, there's no obvious way to check if a page is only half-loaded, than to check if all the basic HTML tags exist and are closed properly.

In Donncha's (WP Super Cache's developer) own words, "It's to stop half generated pages being cached."

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I wish they had the option to cache json specifically, or other data types. So many options and yet not the one we needed for this project. But, this is a cool workaround. I'll give it a try. –  Starfs May 9 '12 at 4:34

It did appear that the json wasn't being cached by wp-super-cache, but we decided to take a different approach. By using the transient api, we were able to do a faux-cache on all json, and drastically reduce the taxing of the database. Then on the ajax side of things, we are caching the html that is created from this semi-cached json. Things are super speedy! Here is a scaled down version of the code and concept.

    $transient_key = 'my-transient-key'; 
    $data = get_transient( $transient_key ); 

    if ( $data == '' ) { 
      $args = array(

    'post_type' => 'brand', 
    'posts_per_page' => 50


  $postsArray = array();  
  // The Query
 query_posts( $args );

  // The Loop
  while ( have_posts() ) : the_post();

    $brand_id = get_the_ID();
    $slug = basename(get_permalink());
    $title = get_the_title();
    $description = get_the_content();

                $posts = array(

                   'brand_id' => $brand_id,
                   'machine_name' => $slug,
                              'postTitle' => $title,
                   'description' => $description,




   $data = json_encode($postsArray);

 set_transient( $transient_key, $data, 60 * 60 * 24 ); // one day
 }  // now all the brand information is cached as one table call.

echo $data;
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nice, thumbs up!!! –  Dipesh Kc Nov 21 '12 at 11:53

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