Alamofire invalid value around character 0

Question

Alamofire.request(.GET, "url").authenticate(user: "", password: "").responseJSON() {
    (request, response, json, error) in
    println(error)
    println(json)

}

This is my request with Alamofire, for a certain request it sometime works, but sometimes i get:

Optional(Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (Invalid value around character 0.) UserInfo=0x78e74b80 {NSDebugDescription=Invalid value around character 0.})

I've read that this can be due to invalid JSON, but the response is a static json string that i have validated in JSON validator as valid. It does contain å ä ö characters and some HTML.

Why am i getting this error sometimes?

Answer 1

I also faced same issue. I tried responseString instead of responseJSON and it worked. I guess this is a bug in Alamofire with using it with django.

Answer 2

In my case , my server URL was incorrect. Check your server URL !!

Answer 3

I got same error while uploading image in multipart form in Alamofire as i was using

multipartFormData.appendBodyPart(data: image1Data, name: "file")

i fixed by replacing by

multipartFormData.appendBodyPart(data: image1Data, name: "file", fileName: "myImage.png", mimeType: "image/png")

Hope this help someone.

Answer 4

May this Help YOu

Alamofire.request(.GET, "YOUR_URL")
     .validate()
     .responseString { response in
         print("Success: \(response.result.isSuccess)")
         print("Response String: \(response.result.value)")
     }

Answer 5

The same issue happened to me and it actually ended up being a server issue since the content type wasn't set.

Adding

.validate(contentType: ["application/json"])

To the request chain solved it for me

Alamofire.request(.GET, "url")
        .validate(contentType: ["application/json"])
        .authenticate(user: "", password: "")
        .responseJSON() { response in
            switch response.result {
            case .Success:
                print("It worked!")
                print(response.result.value)
            case .Failure(let error):
                print(error)
            }
        }

Answer 6

I got the same error. But i found the solution for it.

NOTE 1: "It is not Alarmofire error", it's bcouse of server error.

NOTE 2: You don't need to change "responseJSON" to "responseString".

public func fetchDataFromServerUsingXWWWFormUrlencoded(parameter:NSDictionary, completionHandler: @escaping (_ result:NSDictionary) -> Void) -> Void {

        let headers = ["Content-Type": "application/x-www-form-urlencoded"]
        let completeURL = "http://the_complete_url_here"
        Alamofire.request(completeURL, method: .post, parameters: (parameter as! Parameters), encoding: URLEncoding.default, headers: headers).responseJSON { response in

            if let JSON = response.result.value {
                print("JSON: \(JSON)") // your JSONResponse result
                completionHandler(JSON as! NSDictionary)
            }
            else {
                print(response.result.error!)
            }
        }
    }

Answer 7

This is how I managed to resolve the Invalid 3840 Err.

The error log

 responseSerializationFailed(Alamofire.AFError.ResponseSerializationFailureReason.jsonSerializationFailed(Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 0." UserInfo={NSDebugDescription=Invalid value around character 0.}))

1. It was with Encoding Type used in the Request, The Encoding Type used should be acceptedin your Server-Side.

In-order to know the Encoding I had to run through all the Encoding Types:

default/ methodDependent/ queryString/ httpBody

    let headers: HTTPHeaders = [
        "Authorization": "Info XXX",
        "Accept": "application/json",
        "Content-Type" :"application/json"
    ]

    let parameters:Parameters = [
        "items": [
                "item1" : value,
                "item2": value,
                "item3" : value
        ]
    ]

    Alamofire.request("URL",method: .post, parameters: parameters,encoding:URLEncoding.queryString, headers: headers).responseJSON { response in
        debugPrint(response)
     }

2. It also depends upon the response we are recieving use the appropriate
   • responseString
   • responseJSON
   • responseData

If the response is not a JSON & just string in response use responseString

Example: in-case of login/ create token API :

"20dsoqs0287349y4ka85u6f24gmr6pah"

responseString

Answer 8

I solved using this as header:

let header = ["Content-Type": "application/json", "accept": "application/json"]

Answer 9

In my case, there was an extra / in the URL .

Answer 10

Maybe it is too late but I solved this problem in another way not mentioned here:

When you use .responseJSON(), you must set the response header with content-type = application/json, if not, it'll crash even if your body is a valid JSON. So, maybe your response header are empty or using another content-type.

Make sure your response header is set with content-type = application/json to .responseJSON() in Alamofire work properly.

Answer 11

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

Answer 12

I was sending the improper type (String) to the server in my parameters (needed to be an Int).

Answer 13

Error was resolved after adding encoding: JSONEncoding.default with Alamofire.

  Alamofire.request(urlString, method: .post, parameters: 
  parameters,encoding: 
  JSONEncoding.default, headers: nil).responseJSON {  
   response in
   switch response.result {
                   case .success:
                    print(response)
                    break

                    case .failure(let error):
                     print(error)
        }
   }

Answer 14

The application I was working on this morning had the same error. I believed it to be a server side error since I was unable to upload a user image.

However, upon checking my custom API, I realized that after adding an SSL certificate to my website that I had not updated the api.swift URLs, the data was unable to post:

let HOME_URL = "http://sitename.io"
let BASE_URL = "http://sitename.io/api"
let UPLOAD_URL = "http://sitename.io/api/user/upload"

I changed the URL's to https://. Problem solved.

Answer 15

In my case I have to add this Key: "Accept":"application/json" to my header request.

Something like this:

let Auth_header: [String:String] = ["Accept":"application/json", "Content-Type" : "application/json", "Authorization":"Bearer MyToken"]

I hope that this can help someone.

Answer 16

I face same issue and problem is in params.

let params = [kService: service,
                  kUserPath: companyModal.directory_path,
                  kCompanyDomain: UserDefaults.companyDomain,
                  kImageObject: imageString,
                  kEntryArray: jsonString,
                  kUserToken:  UserDefaults.authToken] as [String : Any]

companyModal.directory_path is url. it coerced from string to any which create issues at server side. To resolve this issue I have to give default value which make it string value.

 let params = [kService: kGetSingleEntry,
                  kUserPath: companyModal.directory_path ?? "",
                  kCompanyDomain: UserDefaults.companyDomain,
                  kUserToken: UserDefaults.authToken,
                  kEntryId: id,
                  ] as [String: Any]

Answer 17

Probably you have "/" at the end of your path. If it is not GET request, you shouldn't put "/" at the end, otherwise you'll get the error

Answer 18

I Changed mimeType from "mov" to "multipart/form-data".

Alamofire.upload(multipartFormData: { (multipartFormData) in
            do {
                let data = try Data(contentsOf: videoUrl, options: .mappedIfSafe)
                let fileName = String(format: "ios-video_%@.mov ", profileID)
                multipartFormData.append(data, withName: "video", fileName: fileName, mimeType: "multipart/form-data")

            } catch  {
                completion("Error")
            }
        }, usingThreshold: .init(), to: url,
           method: .put,
           headers: header)

Worked for me.. :)

Answer 19

For my case:

let header = ["Authorization": "Bearer \(Authserices.instance.tokenid)"]

I forgot the space before \ (after Bearer)

Answer 20

In my case error was due to duplicate email. You can recheck your API on postman to see if response there is OK or not.

Answer 21

In my case, I tried using Postman to get API and this error come from backend.