(Cocoa error 3840.)\" (Invalid value around character 0.) AFNetworking

Question

I've been getting the following error when using the GET method to retrieve a file from a server:

Error: Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (Invalid value around character 0.) UserInfo=0x16e81ed0 {NSDebugDescription=Invalid value around character 0.}

I've tried a number of different things and I believe it could be something to do with the JSON format on the file that I'm trying to get.

Here is the code I've been using:

_username = @"JonDoe";
NSDictionary *parameters = @{ @"username" : _username};
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
manager.responseSerializer = [AFJSONResponseSerializer serializerWithReadingOptions:NSJSONReadingAllowFragments];
manager.responseSerializer.acceptableContentTypes = [NSSet setWithObject:@"text/plain"];

[manager GET:@"http://.........."
  parameters:parameters
     success:^(AFHTTPRequestOperation *operation, id responseObject) {
         NSLog(@"JSON: %@", responseObject);
     } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
         NSLog(@"Error: %@", error);
     }];

My POST method works fine. I just can't seem to fix this issue with the GET. Any ideas? Thank you.

Answer 1

Judging by the discussion in the comments it appears that your GET request is successful (response code 200), but the response body is not valid JSON (nor a JSON fragment) as you have requested by your use of AFJSONResponseSerializer. A basic AFHTTPResponseSerializer can be used for responses that are not JSON.

Answer 2

I am pretty sure that you have a valid response from server but your response is not a valid format in JSON, probably because you have carachters in front of first { . Please try this: Put the same URL address manually in your browser and you will see the culprit in the response. Hope it helped.

Answer 3

Hey guys this is what I found to be my issue: I was calling Alamofire via a function to Authenticate Users: I used the function "Login User" With the parameters that would be called from the "body"(email: String, password: String) That would be passed

my errr was exactly:

optional(alamofire.aferror.responseserializationfailed(alamofire.aferror.responseserializationfailurereason.jsonserializationfailed(error domain=nscocoaerrordomain code=3840 "invalid value around character 0." userinfo={nsdebugdescription=invalid value around character 0

character 0 is the key here: meaning the the call for the "email" was not matching the parameters: See the code below

func loginUser(email: String, password: String, completed: @escaping downloadComplete) { let lowerCasedEmail = email.lowercased()

    let header = [
        "Content-Type" : "application/json; charset=utf-8"
    ]
    let body: [String: Any] = [
        "email": lowerCasedEmail,
        "password": password
    ]

    Alamofire.request(LOGIN_USER, method: .post, parameters: body, encoding: JSONEncoding.default, headers: header).responseJSON { (response) in
        if response.result.error == nil {

            if let data = response.result.value as? Dictionary<String, AnyObject> {
                if let email = data["user"] as? String {
                    self.userEmail = email
                    print(self.userEmail)
                }
                if let token = data["token"] as? String {
                    self.token_Key = token
                    print(self.token_Key)
                }

"email" in function parameters must match the let "email" when parsing then it will work..I no longer got the error...And character 0 was the "email" in the "body" parameter for the Alamofire request:

Hope this helps