How To Make HTTP Requests with WordPress

18 February 2014

In the modern web “means 2.0”, Web applications communicate with each other to gather and share data in between. Your WordPress blog is no exception, that’s why WordPress implemented a smart and powerful class WP_Http since version 2.7.0. This class supports all methods you need to use.

Make Your First Request

You can make HTTP requests within WordPress by using one of these functions.

• wp_remote_get($url, $args): Perform request with GET method
• wp_remote_post($url, $args): Perform request with POST method
• wp_remote_head($url, $args): Perform request HEAD method
• wp_remote_request($url, $args): Perform request and take method as argument

As you see, the first parameter is a string representing a valid site URL, and the second parameter is an optional array of parameters to override the defaults. The syntax of these functions is as follows:

var_dump(wp_remote_get('http://wordpress.org'));
var_dump(wp_remote_post('http://wordpress.org'));
var_dump(wp_remote_head('http://wordpress.org'));
//same requests but with different method
var_dump(wp_remote_request('http://wordpress.org'),array('method'=>'GET'));
var_dump(wp_remote_request('http://wordpress.org'),array('method'=>'POST'));
var_dump(wp_remote_request('http://wordpress.org'),array('method'=>'HEAD'));

The default parameters are the following array:

$defaults = array(
   'method' => 'GET',
   'timeout' => 5,
   'redirection' => 5,
   'httpversion' => '1.0',
   'user-agent' => 'WordPress/version;URL',
   'reject_unsafe_urls' => false,
   'blocking' => true,
   'headers' => array(),
   'cookies' => array(),
   'body' => null,
   'compress' => false,
   'decompress' => true,
   'sslverify' => true,
   'stream' => false,
   'filename' => null,
   'limit_response_size' => null,
);

These functions return an array of response data if the request succeeds and a WP_Error object on failure. You can test the response using is_wp_error. Consider the following example:

$response=  wp_remote_get('http://dsc');
if(is_wp_error($response)){
 echo 'Error Found ( '.$response->get_error_message().' )';
}

Other Useful Functions

Actually wordpress like paradise for developers. along with functions that perform HTTP requests, you can use following functions to quickly access parts of returned array.

• wp_remote_retrieve_body($response): Returns body of the response.
• wp_remote_retrieve_header($response, $header): Returns just one particular header from server response.
• wp_remote_retrieve_response_code($response): Returns just the response code for example 200 (List of response codes).
• wp_remote_retrieve_response_message($response): Returns just response message for example ok.
• wp_remote_retrieve_headers($response): Returns all headers from server response.

For example if you like to check if a link exists and don’t return a 404 message.

function CheckURL($url){
 $response = wp_remote_get($url);
  if(is_wp_error($response))
     //request can't performed
     return 1;
  if(wp_remote_retrieve_response_code($response) == '404')
     //request succeed and link not found
     return 2;
   //request succeed and link exist
   return 3;
}