examples/objc/AppRTCMobile/ARDTURNClient.m

/*
 *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#import "ARDTURNClient+Internal.h"

#import "ARDUtilities.h"
#import "RTCIceServer+JSON.h"

// TODO(tkchin): move this to a configuration object.
static NSString *kTURNRefererURLString = @"https://appr.tc";
static NSString *kARDTURNClientErrorDomain = @"ARDTURNClient";
static NSInteger kARDTURNClientErrorBadResponse = -1;

@implementation ARDTURNClient {
  NSURL *_url;
}

- (instancetype)initWithURL:(NSURL *)url {
  NSParameterAssert([url absoluteString].length);
  if (self = [super init]) {
    _url = url;
  }
  return self;
}

- (void)requestServersWithCompletionHandler:
    (void (^)(NSArray *turnServers, NSError *error))completionHandler {

  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:_url];
  [NSURLConnection sendAsyncRequest:request
                  completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
      if (error) {
        completionHandler(nil, error);
        return;
      }
      NSDictionary *responseDict = [NSDictionary dictionaryWithJSONData:data];
      NSString *iceServerUrl = responseDict[@"ice_server_url"];
      [self makeTurnServerRequestToURL:[NSURL URLWithString:iceServerUrl]
                 WithCompletionHandler:completionHandler];
    }];
}

#pragma mark - Private

- (void)makeTurnServerRequestToURL:(NSURL *)url
             WithCompletionHandler:(void (^)(NSArray *turnServers,
                                             NSError *error))completionHandler {
  NSMutableURLRequest *iceServerRequest = [NSMutableURLRequest requestWithURL:url];
  iceServerRequest.HTTPMethod = @"POST";
  [iceServerRequest addValue:kTURNRefererURLString forHTTPHeaderField:@"referer"];
  [NSURLConnection sendAsyncRequest:iceServerRequest
                  completionHandler:^(NSURLResponse *response,
                                      NSData *data,
                                      NSError *error) {
      if (error) {
        completionHandler(nil, error);
        return;
      }
      NSDictionary *turnResponseDict = [NSDictionary dictionaryWithJSONData:data];
      NSMutableArray *turnServers = [NSMutableArray array];
      [turnResponseDict[@"iceServers"] enumerateObjectsUsingBlock:
                         ^(NSDictionary *obj, NSUInteger idx, BOOL *stop){
          [turnServers addObject:[RTCIceServer serverFromJSONDictionary:obj]];
        }];
      if (!turnServers) {
        NSError *responseError =
          [[NSError alloc] initWithDomain:kARDTURNClientErrorDomain
                                     code:kARDTURNClientErrorBadResponse
                                 userInfo:@{
            NSLocalizedDescriptionKey: @"Bad TURN response.",
            }];
        completionHandler(nil, responseError);
        return;
      }
      completionHandler(turnServers, nil);
    }];
}

@end