如何使用 Alamofire 6 使用 responseDecodable 而不是 responseJSON

Question

One of my apps no longer works due to JSON serialisation failing when using Alamofire.

'responseJSON(queue:dataPreprocessor:emptyResponseCodes:emptyRequestMethods:options:completionHandler:)' is deprecated: responseJSON deprecated and will be removed in Alamofire 6. Use responseDecodable instead.

For code with the following lines

AF.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: [:]).responseJSON { response in.. } 

When changing to

AF.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: [:])
 .responseDecodable { response in... }

Then I get the error

Generic parameter 'T' could not be inferred

So I add the following

AF.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: [:])
  .responseDecodable(of: ResponseType.self) { response in.. } 

I get the error

Cannot find 'ResponseType' in scope

Does anyone have any suggestions?

Answer 1

Unlike .responseJSON which returns a dictionary or array .responseDecodable deserializes the JSON into structs or classes.

You have to create an appropriate model which conforms to Decodable , in your code it's represented by ResponseType(.self) .

The associated value of the success case is the root struct of the model.

But deprecated (in a yellow warning) means the API is still operational.

Side note: A JSON dictionary is never [String: Any?] the value is always non-optional.

Answer 2

In Alamofire -> Documentation/Usage.md, I found the definition of the Decodable, so I try like this, then found working.

struct DecodableType: Decodable { 
    let url: String 
}

AF.request(urlString).responseDecodable(of: DecodableType.self) { response in
    switch response.result {
        case .success(let dTypes):
            print(dTypes.url})
        case .failure(let error):
            print(error)
    }
}