AFNetworking 2.0 AFHTTPSessionManager: how to get status code and response JSON in failure block?

Question

When switched to AFNetworking 2.0 the AFHTTPClient has been replaced by AFHTTPRequestOperationManager / AFHTTPSessionManager (as mentioned in the migration guide). The very

Answer 1

In Swift 2.0 (in case you cannot use Alamofire yet):

Get status code:

if let response = error.userInfo[AFNetworkingOperationFailingURLResponseErrorKey] as? NSHTTPURLResponse {
    print(response.statusCode)
}

Get response data:

if let data = error.userInfo[AFNetworkingOperationFailingURLResponseDataErrorKey] as? NSData {
    print("\(data.length)")
}

Some JSON REST APIs return error messages in their error responses (Amazon AWS services for example). I use this function to extract the error message from an NSError that has been thrown by AFNetworking:

// Example: Returns string "error123" for JSON { message: "error123" }
func responseMessageFromError(error: NSError) -> String? {
    do {
        guard let data = error.userInfo[AFNetworkingOperationFailingURLResponseDataErrorKey] as? NSData else {
            return nil
        }
        guard let json = try NSJSONSerialization.JSONObjectWithData(data, options: .AllowFragments) as? [String: String] else {
            return nil
        }
        if let message = json["message"] {
            return message
        }
        return nil
    } catch {
        return nil
    }
}