title: How to get twitter profile pic using api 1.1 from iOS?
body: <p>I am using MGTwitterEngine lib to authenticate Twitter account, but after successful login I want to get user profile pic but not able to get it and following method is stopped working:</p>
  
  <p><a href="https://api.twitter.com/1.1/users/profile_image?screen_name=username&amp;size=bigger" rel="nofollow">https://api.twitter.com/1.1/users/profile_image?screen_name=username&amp;size=bigger</a></p>
  
  <p>I just tried above method but no success. Then I have did lot of research on it and I finally got following api to get user profile information which include profile pic:</p>
  
  <p><a href="https://api.twitter.com/1.1/users/show.json?screen_name=username" rel="nofollow">https://api.twitter.com/1.1/users/show.json?screen_name=username</a></p>
  
  <p>But this api requires authentication by passing Authorization in Request header which I was not able to generate.</p>
  
  <p>Here is my code which I have tried:</p>
  
  <p>here authdata is the string which I am getting back from MGTwitterEngine lib after successful login.</p>
  
  <pre><code>NSString *authData = [[NSUserDefaults standardUserDefaults] valueForKey:@"authData"];
  NSString *subAuthdata = [authData substringFromIndex:[authData rangeOfString:@"oauth_token_secret="].location];
  subAuthdata = [subAuthdata substringToIndex:[subAuthdata rangeOfString:@"&amp;user_id="].location];
  NSLog(@"%@", subAuthdata);
  
  NSLog(@"encoded: %@", [self base64Encode:subAuthdata]);
  
  NSString *accessTokenHeaderToPost = [NSString stringWithFormat:@"Basic %@", [self base64Encode:subAuthdata]];
  
  NSString  *twitURL = @"https://api.twitter.com/1.1/users/show.json?screen_name=username";
  NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
  [request setURL:[NSURL URLWithString: twitURL]];
  [request setHTTPMethod:@"GET"];
  [request setValue:accessTokenHeaderToPost forHTTPHeaderField:@"Authorization"];
  NSError *err;
  NSURLResponse *response;
  NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&amp;response error:&amp;err];
  NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
  
  NSLog (@"RESP: %@", responseString);
  </code></pre>
  
  <p>But it always says Bad authentication data.</p>
  
  <p>Please help me on this...</p>