Oauth 1a signature example

oauth1-sign.php

<?php
/**
 *  Implementation of the oAuth1 signature spec: http://oauth.net/core/1.0a/ *
 */
namespace Oauth1\Signature;

class TwitterSignature implements \Oauth\Signature
{
    protected $signatureAlgorithm;
    protected $httpMethod;
    protected $authHeader;
    protected $body;
    protected $requestUri;

    public function __construct($signatureAlgorithm, $httpMethod, array $authHeader, $body = null, \Artax\Http\Uri $requestUri)
    {
        if (!$this->isAlgorithmImplemented($signatureAlgorithm)) {
            throw new \Exception('The selected algorithm (`' . $signatureAlgorithm . '`) isn\'t (yet) implemented.');
        }

        $this->signatureAlgorithm = $signatureAlgorithm;
        $this->httpMethod = $httpMethod;
        $this->authHeader = $authHeader;
        $this->body = $body;
        $this->requestUri = $requestUri;
    }

    protected function isAlgorithmImplemented()
    {
        $implementedAlgorithms = array('HMAC-SHA1', 'RSA-SHA1');

        if (!in_array(strtoupper($this->signatureAlgorithm), $implementedAlgorithms)) {
            return false;
        }

        return true;
    }

    public function getSignature()
    {
        return $this->hashString($this->getBaseString(), $this->getSigningKey());
    }

    protected function getBaseString()
    {
        return strtoupper($this->httpMethod) . '&' . rawurlencode($this->requestUri) . '&' . rawurlencode($this->getParameterString());
    }

    protected function getParameterString()
    {
        $baseStringParts = array();
        foreach($this->authHeader as $key => $value) {
            if ($key == 'realm') {
                continue;
            }

            $baseStringParts[rawurlencode($key)] = rawurlencode($value);
        }

        // add $this->body, $this->requestUri

        ksort($baseStringParts);

        $baseString = '';
        $delimiter = '';
        foreach($baseStringParts as $key => $value) {
            $baseString.= $delimiter . $key . '=' . $value;
            $delimiter = '&';
        }

        return $baseStringParts;
    }

    protected function getSigningKey()
    {
        return $this->consumerSecret . '&' . $this->tokenSeret;
    }

    protected function hashString($string, $key)
    {
        switch($this->signatureAlgorithm) {
            case 'HMAC-SHA1':
                return hash_hmac('sha1', $string, $key, true);

            case 'RSA-SHA1':
                return 'real generate hashed string :-)';
        }
    }
}