title: iOS: How to use AFOAuth1Client with given tokens
body: <p>I want to use a REST service, I need OAuth 1 to allow secure authorization.
  I have the consumer key, the consumer secret, the token and the token secret. 
  In PHP I'm using this:</p>
  
  <pre><code>$apiUrl = 'http://www.web.com/api/rest';
  $consumerKey = 'xxxx';
  $consumerSecret = 'yyyyyy';
  $token = 'zzzzz';
  $tokenSecret = 'wwwww';
  
  session_start();
  
  $authType = OAUTH_AUTH_TYPE_AUTHORIZATION;  
  $oauthClient = new OAuth($consumerKey, $consumerSecret, OAUTH_SIG_METHOD_HMACSHA1, $authType);
  $oauthClient-&gt;enableDebug();
  
  $oauthClient-&gt;setToken($token, $tokenSecret);
  $resourceUrl = "$apiUrl"; 
  $headers = array('Content-Type' =&gt; 'application/json');
  
  $oauthClient-&gt;fetch($resourceUrl.'/category/2681', array(), OAUTH_HTTP_METHOD_GET, $headers);
  
  $productsList = $oauthClient-&gt;getLastResponse();
  </code></pre>
  
  <p>In Objective C I'm using AFOAuth1Client, but I don't know when and how to set the token in the AFOAuth1Client object like $oauthClient->setToken($token, $tokenSecret);</p>
  
  <pre><code>AFOAuth1Client *oAuth1Client = [[AFOAuth1Client alloc] initWithBaseURL:[NSURL URLWithString:kUrlPre] key:@"consumerKey" secret:@"consumerSecret"];
  
  oAuth1Client.signatureMethod = AFHMACSHA1SignatureMethod;
  oAuth1Client.accessToken = [[AFOAuth1Token alloc] initWithKey:@"consumerKey" secret:@"consumerSecret" session:nil expiration:nil renewable:YES]; //I have tried this, but when I add this line I'm getting this error: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** setObjectForKey: object cannot be nil (key: oauth_token)' in authorizeUsingOAuthWithRequestTokenPath 
  
  [oAuth1Client authorizeUsingOAuthWithRequestTokenPath:@"http://www.web.com/api/rest/category/2681"
                                      userAuthorizationPath:nil //??
                                                callbackURL:nil //I don't need it
                                            accessTokenPath:nil //I don't need it
                                               accessMethod:@"GET"
                                                      scope:nil 
                                                    success:^(AFOAuth1Token *accessToken, id responseObject) {
                                                        NSLog(@"Success: %@", accessToken);
                                                    } failure:^(NSError *error) {
                                                        NSLog(@"Error: %@", error);
                                                    }];
  </code></pre>
  
  <p>I think I'm using bad uthorizeUsingOAuthWithRequestTokenPath. How can I parse my PHP code to Objective C. I'm opened to use other OAuth frameworks.</p>