"Incorrect JSON format" - json

Question

I am making a POST request with required body parameters, testing this POST request in POSTMAN gives me correct response, but when I am passing same body parameters from my code I am getting below error-:
Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.
Code -:
func submitStudentAttendance(url:String,id:String,SessionID: Int,SchoolID:Int,BatchID:Int,ClassID:Int,SectionID:Int,Medium:Int,Date:String,accessToken:String) {
let params : [String:Any] = [
"$id":"1",
"SchoolID":1,
"SessionID":42,
"BatchID":106,
"ClassID":634,
"SectionID":1246,
"Medium":"English",
"Date":"0001-01-01T00:00:00",
"CreatedBy":118,
"CreatedOn":"2019-04-14T17:02:34",
"studentList":"",
"AttendenceData":"[{\"ID\":0,\"SchoolID\":null,\"SessionID\":null,\"ClassID\":634,\"SectionID\":1246,\"StudID\":\"DSM00399\",\"SubjectID\":null,\"Date\":\"0001-01-01T00:00:00\",\"Attendence\":\"P\",\"CreatedOn\":null,\"CreatedBy\":0,\"IsActive\":null,\"Remarks\":\"rem16\",\"timeID\":null,\"AtndType\":null,\"BatchID\":null,\"Medium\":null}]"
]
let urlRequest = NSURL(string: url)
var request = URLRequest(url: urlRequest! as URL)
let tokenString = "Bearer " + accessToken
request.httpMethod = "POST"
request.setValue(tokenString, forHTTPHeaderField: "Authorization")
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
let data = try! JSONSerialization.data(withJSONObject: params, options: [])
let json = NSString(data: data, encoding: String.Encoding.utf8.rawValue)
if let json = json {
print(json)
}
request.httpBody = json!.data(using: String.Encoding.utf8.rawValue);
let alamoRequest = Alamofire.request(request as URLRequestConvertible)
alamoRequest.responseString {
response in
switch response.result {
case .success:
if response.data != nil {
do{
let json = try JSON(data: response.data!)
print(json)
}catch{
print(error)
}
}
break
case .failure(let error):
print(error)
}
}
}
The body part is exactly same as in POSTMAN, but still not working. Can anyone let me know what's going wrong here? Is this server side issue or I am sending body request in wrong format?
POSTMAN RESPONSE -:

Answer 1

When the params as declared in your question is converted into JSON, it looks like this. Here, AttendanceData value is not converted as proper JSON structure. It looks like a string.
JSON from your param:
{
"Date": "0001-01-01T00:00:00",
"CreatedBy": 118,
"$id": "1",
"BatchID": 106,
"ClassID": 634,
"Medium": "English",
"studentList": "",
"SchoolID": 1,
"SectionID": 1246,
"AttendenceData": "[{\"ID\":0,\"SchoolID\":null,\"SessionID\":null,\"ClassID\":634,\"SectionID\":1246,\"StudID\":\"DSM00399\",\"SubjectID\":null,\"Date\":\"0001-01-01T00:00:00\",\"Attendence\":\"P\",\"CreatedOn\":null,\"CreatedBy\":0,\"IsActive\":null,\"Remarks\":\"rem16\",\"timeID\":null,\"AtndType\":null,\"BatchID\":null,\"Medium\":null}]",
"CreatedOn": "2019-04-14T17:02:34",
"SessionID": 42
}
But if you declare param as shown below, and converted to JSON, AttendanceData value is properly converted to JSON.
let params : [String:Any] = [
"$id":"1",
"SchoolID":1,
"SessionID":42,
"BatchID":106,
"ClassID":634,
"SectionID":1246,
"Medium":"English",
"Date":"0001-01-01T00:00:00",
"CreatedBy":118,
"CreatedOn":"2019-04-14T17:02:34",
"studentList":"",
"AttendenceData":[
"ID":0,"SchoolID":"null","SessionID":"null","ClassID":634,"SectionID":1246,"StudID":"DSM00399","SubjectID":"null","Date":"0001-01-01T00:00:00","Attendence":"P","CreatedOn":"null","CreatedBy":0,"IsActive":"null","Remarks":"rem16","timeID":"null","AtndType":"null","BatchID":"null","Medium":"null"
]
]
JSON
{
"$id": "1",
"BatchID": 106,
"CreatedBy": 118,
"ClassID": 634,
"studentList": "",
"SectionID": 1246,
"SessionID": 42,
"AttendenceData": {
"IsActive": "null",
"AtndType": "null",
"SectionID": 1246,
"timeID": "null",
"SessionID": "null",
"Attendence": "P",
"Date": "0001-01-01T00:00:00",
"Remarks": "rem16",
"Medium": "null",
"SchoolID": "null",
"BatchID": "null",
"ClassID": 634,
"StudID": "DSM00399",
"SubjectID": "null",
"CreatedBy": 0,
"ID": 0,
"CreatedOn": "null"
},
"Date": "0001-01-01T00:00:00",
"CreatedOn": "2019-04-14T17:02:34",
"Medium": "English",
"SchoolID": 1
}
Hope it could also solve your problem.