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?

One thing I like to do when I get this error is comment out the `responseJSON() { ... }` block and replace with `.responseString { _, _, s, _ in println(s) }`. That lets you see the json that is returned to look for any odd text that would make it unparsible by `responseJSON` — ad121, Sep 02 '15 at 15:23
I get a status code of 200 and I get this error. AHHH. Brain death in my case :). I wasn't actually returning JSON from the server. That solves it. — Chris Prince, Nov 22 '15 at 23:49

score 153 · Accepted Answer · edited Oct 07 '18 at 13:23

153

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.

edited Oct 07 '18 at 13:23

Lukas Würzburger

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answered Nov 05 '15 at 09:58

Smit

1,696
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3

Thanks for pointing that out. I was using responseJSON but the actual response from the server was in XML format! Saved me the headache :) – C0D3 Dec 07 '15 at 22:43
saved my project after hours facing this problem.I should set response in JSON format within my server. I was not doing this, but once I did, I could use responseJSON from alamofire – guijob Dec 14 '16 at 22:16
If you are using GET then you need to check with responseString only otherwise for POST check it using responseJSON. Reference: https://grokswift.com/updating-alamofire-to-swift-3-0/ – Anurag Sharma Jan 27 '17 at 05:21
I lost customers because of this issue in my iOS app. – Jaseem Abbas Mar 21 '17 at 09:44
@Smit Thakkar how would you parse the json response from the string?, i´m receiving this response but i cannot use responseJSON due to the html error message but i need to process the json anyways "
\nNotice: Undefined offset: 0 in server/file on line 357
\n
\nNotice: Undefined offset: 0 in server/file on line 358
\n{\"status\":\"success\",\"desc\":\"all proceed",\"data\":[{\"token\":\"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJyZW50aS5teCIsImF1ZCI6Imh0dHBzOlwvXC9yZW50aS5teCIsImlhdCI6MTQ5MzYwMzY2MCwiZXhwIjox\"}]}" – Cesar Mtz May 01 '17 at 01:56
1

Your response is messed up with html, you need to parse the html and get the json string out and convert it to dictionary. I recommend trying out SwiftSoup or for better alternatives to parseHtml look at http://stackoverflow.com/questions/31080818/what-is-the-best-practice-to-parse-html-in-swift. – Smit May 01 '17 at 04:34
making above change again returning this error `The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.` while it is wokring well on `Postman` – Vaibhav Saran Aug 27 '17 at 17:43
@VaibhavSaran can you put the gist of your code snippet and also tell me the status code that you are getting. – Smit Nov 06 '17 at 12:56
Authorization is need to apply forcefully then you dont need to change it to "responcestring" Keep responseJSON as it is. – Yogesh Dalavi Dec 26 '18 at 12:27
THANK YOU! This was exactly what I needed! – lizziepika Mar 07 '19 at 00:36

Saeed · Answer 2 · 2021-04-23T10:34:08.293

11

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

edited Apr 23 '21 at 10:34

answered Jun 24 '19 at 11:22

Saeed

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This was the issue for me. I can't believe I missed it. I have to make a habit of checking the URL first, and always! – LondonGuy Jun 16 '20 at 19:51

score 9 · Answer 3 · answered Feb 22 '16 at 10:35

9

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.

answered Feb 22 '16 at 10:35

Avijit Nagare

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I had hours trying to figure this out. I wonder why this solution works... Thank you! – MVZ Oct 10 '16 at 20:18

score 8 · Answer 4 · answered Jul 18 '16 at 08:56

8

May this Help YOu

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

answered Jul 18 '16 at 08:56

Krutarth Patel

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Yes Bro.i inspired from your answer. i just upload code for any fresher – Krutarth Patel Jul 18 '16 at 09:57

score 7 · Answer 5 · answered Jul 01 '16 at 04:09

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)
            }
        }

score 4 · Answer 6 · answered Feb 15 '17 at 07:43

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!)
            }
        }
    }

Ratz · Answer 7 · 2017-12-28T09:11:25.833

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.}))

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)
     }

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

score 3 · Answer 8 · answered May 19 '18 at 20:43

3

I solved using this as header:

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

answered May 19 '18 at 20:43

Bruno Muniz

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score 2 · Answer 9 · answered Apr 29 '19 at 12:06

2

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

answered Apr 29 '19 at 12:06

Alok

266
2
11

score 1 · Answer 10 · answered Oct 22 '16 at 21:32

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.

score 1 · Answer 11 · answered Nov 14 '17 at 18:20

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

score 1 · Answer 12 · answered Jul 19 '18 at 00:33

1

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

answered Jul 19 '18 at 00:33

agrippa

819
10
8

score 1 · Answer 13 · answered Aug 21 '18 at 13:05

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)
        }
   }

score 0 · Answer 14 · answered Nov 22 '16 at 19:47

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.

score 0 · Answer 15 · answered Aug 18 '17 at 02:22

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.

score 0 · Answer 16 · answered Jul 21 '18 at 06:16

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]

score 0 · Answer 17 · answered Nov 25 '18 at 12:06

0

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

answered Nov 25 '18 at 12:06

Mark Darry

27
7

score 0 · Answer 18 · answered Jul 08 '19 at 09:11

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.. :)

score 0 · Answer 19 · edited Nov 05 '19 at 17:52

0

For my case:

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

I forgot the space before \ (after Bearer)

edited Nov 05 '19 at 17:52

Studocwho

2,404
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answered Nov 05 '19 at 16:38

haggag

1
2

score 0 · Answer 20 · answered Apr 09 '20 at 16:18

0

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.

answered Apr 09 '20 at 16:18

Arqam Butt

31
1

score 0 · Answer 21 · answered Sep 24 '20 at 03:20

0

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

answered Sep 24 '20 at 03:20

Diệp Lân

21
2

Alamofire invalid value around character 0

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