Alamofire invalid value around character 0

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.

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.

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)
}
}

May this Help YOu

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

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.

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.

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!)
}
}
}

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.

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

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 solved using this as header:

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

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

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]

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)
}
}

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

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

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

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.