Alamofire: Serializer reports success when HTTP response is 500

[josephknelf]

I am uploading a file to a server which responds, occasionally, with an error 500. The problem is that the result is marked as a success and this confuses my client code something fierce. Here's an example of the problem:

     let endpointUrl = NSURL("http://aserver.com/somepath/uploadImageEndpoint")

    let cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData

    let request = NSMutableURLRequest(URL: endpointUrl!, cachePolicy: cachePolicy, timeoutInterval: 60.0)
    request.HTTPMethod = "POST"

    // set credentials
    let userCredentials = UserCredentials()
    let base64EncodedCredentials = userCredentials.base64EncodedCredentials()
    request.setValue("Basic \(base64EncodedCredentials)", forHTTPHeaderField: "Authorization")

    // set boundary
    let boundary = "NET-POST-boundary-\(arc4random())-\(arc4random())"
    request.setValue("multipart/form-data;boundary="+boundary,
        forHTTPHeaderField: "Content-Type")

    // create request parameters
    let parameters = NSMutableData()
    for s in ["\r\n--\(boundary)\r\n",
        "Content-Disposition: form-data; filename=\"userimage.png\"\r\n",
        "Content-Type: image/png\r\n\r\n"] {
            parameters.appendData(s.dataUsingEncoding(NSUTF8StringEncoding)!)
    }
    parameters.appendData(UIImagePNGRepresentation(image)!)
    parameters.appendData("\r\n--\(boundary)--\r\n"
        .dataUsingEncoding(NSUTF8StringEncoding)!)

    upload(request, data: parameters).responseData() { (_, response, result) in
        if(response?.statusCode == 500) {
            NSLog("@@@@@@@@@@@@@@@ Received 500")
        }
        if(result.isSuccess) {
            NSLog("@@@@@@@@@@@@@@@ result is success")
        }
        if(result.isFailure) {
            NSLog("@@@@@@@@@@@@@@@ result is failure")
        }
        switch result {
            case .Success(_):
                successHandler()
            case .Failure(_, let error):
                let nsError = error as NSError
                errorHandler(nsError)
        }
    }

This will output:

@@@@@@@@@@@@@@@ Received 500
@@@@@@@@@@@@@@@ result is success

I don't believe this an intuitive result. The result should be a failure if the server returns a 500.

This issue was encountered in XCode 7.0.1 running an iPhone 6 simulator which is simulating iOS 9.0.1

[jshier]

By default Alamofire registers any response that makes it through the response serializer (in your example, the dataResponseSerializer used by .responseData) as a success. If you wish to validate the response code of your request, just add a .validate() to your request chain. This will ensure that your response code is between 200 and 299, inclusive. You can also customize validation using the methods described in the documentation.

[josephknelf]

Thank you Jon, great response!