From time to time I find myself using the JSON API plugin for WordPress – it works good, and is handy for providing connectivity with mobile apps. Just form a query, snag the data, sort out what you need, and done. Nice.
Except – one of the projects I’ve got involves a LOT of data. The initial download for a user could be as much as 480k – might not seem like a lot, but when it comes to mobile download speeds, that can really slow things down. So the first step it to see if the client needs to update at all – the easy way is to check to see how many posts are on the server and compair that with the local client.
JSON API plugin doesn’t support just getting a count for posts of a single category. Hm.
So, a quick hack to fix that (and, potentially, could be expanded to do a few other things). Open up jsonapi/controllers/core.php – we’ll make two changes. First, hunt down “public function get_category_posts()”. Below it’s closing for the function, add:
public function get_category_posts_count() {
global $json_api;
$category = $json_api->introspector->get_current_category();
if (!$category) {
$json_api->error("Not found.");
}
$posts = $json_api->introspector->get_posts(array(
'cat' => $category->id
));
return $this->posts_object_result($posts, $category, 1);
}
(There’s only two things different in there – a new function name that adds _count to the name, and a third parameter for the post object call)
Now, scroll down to the bottom of the file and find function posts_object_result(…). Replace it with:
protected function posts_object_result($posts, $object, $skipData = 0) {
global $wp_query;
// Convert something like "JSON_API_Category" into "category"
$object_key = strtolower(substr(get_class($object), 9));
if($skipData == 1) {
return array(
'count' => count($posts),
'pages' => (int) $wp_query->max_num_pages,
$object_key => $object
);
} else {
return array(
'count' => count($posts),
'pages' => (int) $wp_query->max_num_pages,
$object_key => $object,
'posts' => $posts
);
}
}
Now, to get just a count of the posts, with titles but no article data, example.com/api/get_category_post_counts/?slug=whatevercategoryslug will return something like:
{"status":"ok","count":1,"pages":1,"category":{"id":1147,"slug":"my-articles","title":"My Article","description":"","parent":0,"post_count":1}}
Piece of cake. It could be applied to tags and just about any other item easily.