如何同步使用AFNetworking 2.0庫？

Question

使用AFNetworking 2.0下面的代碼是有效的，通過互聯網來獲取數據：

NSString *URLPath = @"http://www.raywenderlich.com/downloads/weather_sample/weather.php?format=json"; 
NSDictionary *parameters = nil; 

[[AFHTTPRequestOperationManager manager] GET:URLPath parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) { 
    NSLog(@"success: %@", responseObject); 

} failure:^(AFHTTPRequestOperation *operation, NSError *error) { 
    NSLog(@"failure: %@", error); 
}]; 

但我想在單元測試同步測試這些請求。

// This code would be blocked. 
dispatch_semaphore_t sema = dispatch_semaphore_create(0); 

NSString *URLPath = @"http://www.raywenderlich.com/downloads/weather_sample/weather.php?format=json"; 
NSDictionary *parameters = nil; 

[[AFHTTPRequestOperationManager manager] GET:URLPath parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) { 
    NSLog(@"success: %@", responseObject); 
    dispatch_semaphore_signal(sema); 

} failure:^(AFHTTPRequestOperation *operation, NSError *error) { 
    NSLog(@"failure: %@", error); 
    dispatch_semaphore_signal(sema); 

}]; 

dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER); 
dispatch_release_ARC_compatible(sema); 

我如何可以獲取使用AFNetworking 2.0庫同步數據（測試中Kiwi這些代碼）：但是，如果使用這樣當GCD信號受阻？

Answer 1

您的信號量將被阻止，因爲默認情況下AFNetworking在主循環上運行。所以如果你在等待信號量的主循環，AFNetworking的代碼永遠不會運行。

爲了解決這個問題，你只需告訴AFNetworking使用不同的調度隊列。你這樣做，通過設置AFHTTPRequestOperationManager

您可以創建自己的調度隊列，或使用預定義者之一的operationQueue財產，像這樣：

// Make sure that the callbacks are not called from the main queue, otherwise we would deadlock 
manager.operationQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);