Posting JSON strings with Kohana 3.2 in PHP

When running normal post operations I use the following code:

 $request = Request::factory($url)->method(Request::POST)->post($params);
 $response = $request->execute();

I'm not sure what it is I need to change though to enable me to POST a json string instead of an array variable.

My json string is basically created using the json_encode() function on an array of parameters, like so:

$params = array(
    'var1' => $var1开发者_Python百科,
    'var2' => $var2,
    // etc
);

$json = json_encode($params);

Any help would be greatly appreciated.

I have found these solutions.

Using PUT:

$request = Request::factory('http://example.com/put_api')->method(Request::PUT)->body(json_encode('the body'))->headers('Content-Type', 'application/json');

Using POST:

$request = Request::factory('http://example.com/post_api')->method(Request::POST)->body(json_encode('the body'))->headers('Content-Type', 'application/json');

From here: http://kohanaframework.org/3.2/guide/kohana/requests#external-requests