Date string does not match format expected by formatter - json

Question

Was only able to reproduce this issue on a friend's device. The device is from Germany and is set to the German region in Settings. I cannot reproduce on any Canadian devices. Why is it failing when trying to create a Date property from the JSON?
Console:
dataCorrupted(Swift.DecodingError.Context(codingPath: [_JSONKey(stringValue: "60", intValue: nil), CodingKeys(stringValue: "expiration", intValue: nil)], debugDescription: "Date string does not match format expected by formatter.", underlyingError: nil))
Struct:
struct TokenResponse: Decodable {
var ticket : String
var expiration : Date?
var sessionId: String
}
Inside URLSession:
do {
let decoder = JSONDecoder()
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
decoder.dateDecodingStrategy = .formatted(formatter)
let json = try decoder.decode([String: TokenResponse].self, from: data)
}
catch {
print(error)
}
JSON:
{
"60":{
"ticket":"aVeryLongJWT",
"expiration":"2022-02-04T22:00:34.8325102Z",
"sessionId":"aUUID"
}
}

Answer 1

You should set the locale before setting dateFormat string:
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
See “Working With Fixed Format Date Representations” in DateFormatter documentation.

Answer 2

Previous answer is worked for me! You should check the date format coming from server. Mine was different and its case sensitive. I just arranged df.dateFormat Good luck!
private let dateFormatter: DateFormatter = {
let df = DateFormatter()
df.locale = Locale(identifier: "en_US_POSIX")
df.dateFormat = "yyyy-MM-dd'T'HH:mm:ss-hh:ss"
return df
}()
and then in the dataFetch function
do {
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(self.dateFormatter)
let results = try! decoder.decode(Model.self, from: data)
print(results)
} catch {
print("Decoding Error!")
}