Alamofire invalid value around character 0

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?

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.

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

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.

May this Help YOu

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

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)
            }
        }

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!)
            }
        }
    }

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

I solved using this as header:

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

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

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.

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

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

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)
        }
   }

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.

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.

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]

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

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.. :)

For my case:

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

I forgot the space before \ (after Bearer)

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.

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