How to handle two different JSON responses with Alamofire - swift

Question

I am making a login functionality in a SwiftUI app.
When the login in successful the JSON response is:
{
"user_id": 41,
"token": "Token",
"token_type": "bearer",
"expires_in": 12096000
}
When the login is failed the JSON response is:
{
"message": "this is a failure message"
}
I made two different structs to encode the responses
struct LoginResponseModelFailure:Codable {
let message:String
}
struct LoginResponseModelSuccess:Codable{
let user_id: Int
let token: String
let token_type : String
let expires_in: Int
}
Do I need to merge these two structs to single one? if so how to do that?
How can I handle two different responses using alamofire or urlSession?

Answer 1

To avoid optionals my suggestion is to declare the root object as enum with associated values
enum Response : Decodable {
case success(ResponseSuccess)
case failure(ResponseFailure)
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
do {
self = .success(try container.decode(ResponseSuccess.self))
} catch {
self = .failure(try container.decode(ResponseFailure.self))
}
}
}
The other structs can remain as they are except the names became camelCase
struct ResponseFailure : Decodable {
let message : String
}
struct ResponseSuccess : Decodable {
let userId : Int
let token : String
let tokenType : String
let expiresIn : Int
}
To decode the data switch on the result, data represents the received raw data. The key decoding strategy is added to handle the snake_case keys
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let result = try decoder.decode(Response.self, from: data)
switch result {
case .success(let data): print(data)
case .failure(let error): print(error)
}
} catch {
print(error)
}

Answer 2

As mentioned in the comment, one way is to create one Struct but then you have to make all the properties Optional as below,
struct LoginResponse: Codable {
let user_id: Int?
let token: String?
let token_type : String?
let expires_in: Int?
let message: String?
}
So now you have to deal with all the optionals.
Another way that seems more appropriate is to introduce another Struct that holds success and failure but you have to implement the init(from decoder: Decoder) method as below,
struct LoginFailure: Codable {
let message:String
}
struct LoginSuccess: Codable {
let user_id: Int
let token: String
let token_type : String
let expires_in: Int
}
struct LoginRespone: Codable {
var data: LoginSuccess?
var message: LoginFailure?
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
if let data = try? container.decode(LoginSuccess.self) {
self.data = data
} else {
self.message = try container.decode(LoginFailure.self)
}
}
}
let success = """
{
"user_id": 41,
"token": "Token",
"token_type": "bearer",
"expires_in": 12096000
}
""".data(using: .utf8)!
let failure = """
{
"message": "this is a failure message"
}
""".data(using: .utf8)!
do {
let r = try JSONDecoder().decode(LoginRespone.self, from: failure)
print(r.message?.message)
} catch {
print(error)
}

Answer 3

You can use one structure to handle the response. Based on status code, you can differentaite the response.
struct LoginModel:Codable {
let message:String
let userId: Int
let token: String
let tokenType : String
let expiresIn: Int
enum CodingKeys : String,CodingKey {
case message, token
case userId = "user_id"
case tokenType = "token_type"
case expiresIn = "expires_in"
}
init(from decoder: Decoder) throws {
let value = try decoder.container(keyedBy: CodingKeys.self)
self.message = try value.decodeIfPresent(String.self, forKey: .message) ?? ""
self.userId = try value.decodeIfPresent(Int.self, forKey: .userId) ?? 0
self.token = try value.decodeIfPresent(String.self, forKey: .token) ?? ""
self.tokenType = try value.decodeIfPresent(String.self, forKey: .tokenType) ?? ""
self.expiresIn = try value.decodeIfPresent(Int.self, forKey: .expiresIn) ?? 0
}
}