Create a XML and JSON web service using WordPress

In this article, we are going to discuss about How to create a XML and JSON web service using Wordpress. WordPress started in 2003 with a single bit of code to enhance the typography of everyday writing and with fewer users than you can count on your fingers and toes. Since then it has grown to be the largest self-hosted blogging tool in the world, used on millions of sites and seen by tens of millions of people every day.

Create a wordpress page and call it json or whatever you like and then add a json.php file within your wordpress theme then add the code below.

<?php
/*
Template Name: json
*/

/* require the user as the parameter */
if(isset($_GET['user']) && intval($_GET['user'])) {

  /* soak in the passed variable or set our own */
  $number_of_posts = isset($_GET['num']) ? intval($_GET['num']) : 10; //10 is the default
  $format = strtolower($_GET['format']) == 'json' ? 'json' : 'xml'; //xml is the default
  $user_id = intval($_GET['user']); //no default

  /* connect to the db */
  global $wpdb;

  /* create one master array of the records */
  $posts = array();
  
  $the_query = new WP_Query( "author=$user_id&showposts=$number_of_posts" );

  while ( $the_query->have_posts() ) : $the_query->the_post();
         
// add any extras that you would like to this array 
$posts[] = array('title'=> get_the_title(),'content'=>get_the_content(),'link'=>get_permalink(get_the_ID()));

  endwhile;


  /* output in necessary format */
  if($format == 'json') {
    header('Content-type: application/json');
    echo json_encode(array('posts'=>$posts));
  }
  else {
    header('Content-type: text/xml');
    echo '<posts>';
    foreach($posts as $index => $post) {
      if(is_array($post)) {
        foreach($post as $key => $value) {
          echo '<',$key,'>';
          if(is_array($value)) {
            foreach($value as $tag => $val) {
              echo '<',$tag,'>',htmlentities($val),'</',$tag,'>';
            }
          }
          echo '</',$key,'>';
        }
      }
    }
    echo '</posts>';
  }

  /* reset query */
  wp_reset_postdata();
}

http://example.co.uk/json/?user=1&num=3&format=json