Sorting results from JSON-API on custom fields

Looking through the source code, this plugin maps the query variable orderby to the WP_Query argument of the same name, orderby.

What this means is that you should be able to do the following: http://www.example.com/wordpress/?json=get_author_posts&author_slug=user&post_type=custom&include=title,custom_fields&custom_fields=date_value&count=10&page=1&orderby=date_value

You can sort via javascript .sort() a json array.

Your example string was also splitable via php, like explode()

explode( '&', $your_string );

or parse_url

For sorting a JSON with php use usort; do you find solutions via G* search.

Also you can use json_decode(), my favorite way, and create a php array from the json object and use on of different php functions to sort this array.

I'm new to JSON API but this worked for me.

This answer is inspired by https://wordpress.stackexchange.com/a/18200 and documentation about JSON API external controller as described: here

First create your controller file mikictrl.php, in your theme directory.

class JSON_API_Mikictrl_Controller {

  public function get_custom_posts() {
  global $json_api;

  // See also: http://codex.wordpress.org/Template_Tags/query_posts
  $posts = $json_api->introspector->get_posts(array(
    'meta_key' => $json_api->query->key,
    'meta_value' => $json_api->query->value,
    'orderby' => $json_api->query->key
  ));

  return array(
    'key' => $json_api->query->key,
    'value' => $json_api->query->value,
    'posts' => $posts
  );
 }
}

Then add following to your theme's functions.php

// Add a custom controller
add_filter('json_api_controllers', 'add_my_controller');
function add_my_controller($controllers) {
  $controllers[] = 'Mikictrl';
  return $controllers;
}

// Register the source file for our controller
add_filter('json_api_mikictrl_controller_path', 'mikictrl_controller_path');
function mikictrl_controller_path($default_path) {
  return get_stylesheet_directory() . '/mikictrl.php';
}

And last, go to JSON API in wordpress admin, and enable the Mikictrl controller.

Now you can sort a query by meta_key of your custom fields :

http://example.com/api/Mikictrl/get_custom_posts/?key=_yourcustomfieldkey&custom_fields=_yourcustomfieldkey&order=desc&include=title,custom_fields&dev=1

Also, you can filter by a meta_value if you fill the value parameter :

http://example.com/api/Mikictrl/get_custom_posts/?key=_yourcustomfieldkey&value=yourcustomfieldvalue&custom_fields=_yourcustomfieldkey&order=desc&include=title,custom_fields&dev=1