PHP Oauth Invalid signature issue

Question

I am trying to start with OAuth 1.0 in PHP and I faced weird problem. I created pseudo-Consumer which generates signature according to specification and sends it with used parameters via POST to Provider. Consumer uses:

$oauth_consumer_key = '123';
$oauth_consumer_secret = '456';

$oauth_signature_method = 'HMAC-SHA1';
$oauth_timestamp = time();
$oauth_nonce = uniqid();
$oauth_version = '1.0';
$oauth_callback = 'http://localhost/oauth/callback';

$oauth = new OAuth($oauth_consumer_key, $oauth_consumer_secret);
$oauth->enableDebug();

$oauth_signature = $oauth->generateSignature('POST', $oauth_callback, array($oauth_consumer_key, $oauth_signature_method, $oauth_timestamp, $oauth_nonce, $oauth_version));

On Providers side everything seems to work as intended. All values are received:

object(OAuthProvider)[1]
  public 'consumer_key' => string '123' (length=3)
  public 'consumer_secret' => string '456' (length=3)
  public 'nonce' => string '5390610001c90' (length=13)
  public 'token' => null
  public 'token_secret' => null
  public 'timestamp' => string '1401970944' (length=10)
  public 'version' => string '1.0' (length=3)
  public 'signature_method' => string 'HMAC-SHA1' (length=9)
  public 'callback' => string 'http://localhost/oauth/callback' (length=31)
  public 'request_token_endpoint' => boolean true
  public 'signature' => string '8lNbnGTOen4TEOHS9KcpgCiBl+M=' (length=28)

But this is the end of honeymoon - attempt to verify signature causes error: signature_invalid . This is what I used on Providers side:

$provider = new OAuthProvider();
$provider->isRequestTokenEndpoint(true);
$provider->consumerHandler('lookupConsumer');
$provider->timestampNonceHandler('timestampNonceChecker');

try
{
    $request_verified = $provider->checkOAuthRequest();
}
catch(OAuthException $e)
{
    echo $provider->reportProblem($e);
}

and what I receive as an problem report:

oauth_problem=signature_invalid&debug_sbs=POST&http%3A%2F%2Flocalhost%2Foauth%2Fcustom_auth%2Frequest_token.php&oauth_callback%3Dhttp%253A%252F%252Flocalhost%252Foauth%252Fcallback%26oauth_consumer_key%3D123%26oauth_nonce%3D5390610001c90%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1401970944%26oauth_version%3D1.0

As an addition what baffles me is that when I use generateSignature for the same constant parameters (for debugging I set timestamp and nonce to constant values) it gives me every time different value like if there still was some random element I am not aware of. As a validation sample - hash_hmac does not have such issue.

Am I missing something or is there a problem with official PHP OAuth implementation ( http://pecl.php.net/package/oauth )?

Answer 1

I have been scratching my head with this exact question for almost a week now because of lack of documentation but this is what solved everything for me.

It seems the OAuth class does its own request signing. I had done the exact same steps as you to no avail but once I removed all the parameters and just called fetch/getRequestToken on my url it all worked.

My code that works

$consumer_key      = 'key';
$consumer_secret   = 'secret';
$request_token_url = 'http://someurl.com/oauth/request-token';

$oauth = new OAuth($consumer_key, $consumer_secret);
$oauth->enableDebug(); //helpful debug

try {
    $oauth->getRequestToken($request_token_url);
} catch (OAuthException $e) {
    echo OAuthProvider::reportProblem($e); //easier to debug oauth exceptions
}

//this should hold the `request_token` and `request_token_secret` parameters for you to call getAccessToken
$response = json_decode($oauth->getLastResponse());

I have my own provider set up at http://someurl.com/oauth/request-token that looks like:

$provider = new OAuthProvider();
$provider->consumerHandler(array($this,'consumerHandler'));
$provider->timestampNonceHandler(array($this,'timestampNonceHandler'));
$provider->tokenHandler(array($this,'tokenHandler'));
$provider->setRequestTokenPath('/oauth/request-token');

try {
    $request_verified = $provider->checkOAuthRequest();
} catch(OAuthException $e) {
    echo $provider->reportProblem($e);
}
//provider now holds all the required timestamp, nonce, and signature

I hope this helps, even though it's a year after