Pony.fm/app/Library/Poniverse/httpful/examples/override.php

<?php
require(__DIR__ . '/../bootstrap.php');

// We can override the default parser configuration options be registering
// a parser with different configuration options for a particular mime type

// Example setting a namespace for the XMLHandler parser
$conf = ['namespace' => 'http://example.com'];
\Httpful\Httpful::register(\Httpful\Mime::XML, new \Httpful\Handlers\XmlHandler($conf));

// We can also add the parsers with our own...
class SimpleCsvHandler extends \Httpful\Handlers\MimeHandlerAdapter
{
    /**
     * Takes a response body, and turns it into
     * a two dimensional array.
     *
     * @param string $body
     * @return mixed
     */
    public function parse($body)
    {
        return str_getcsv($body);
    }

    /**
     * Takes a two dimensional array and turns it
     * into a serialized string to include as the
     * body of a request
     *
     * @param mixed $payload
     * @return string
     */
    public function serialize($payload)
    {
        $serialized = '';
        foreach ($payload as $line) {
            $serialized .= '"' . implode('","', $line) . '"' . "\n";
        }
        return $serialized;
    }
}

\Httpful\Httpful::register('text/csv', new SimpleCsvHandler());