Question

我试图将请求响应（以JSON的形式）序列化为模型 - JSON可能有时会遗漏某些属性，因此我尝试使用方法here来保护反对。

但是，模型从模型中抛出经典的fatal error: unexpectedly found nil while unwrapping an Optional value - 模型试图强制从responseObject JSON中打开init调用的非可选值 - 但是因为它没有存在，力量展开失败。

从Alamofire处理此问题的最佳解决方案是什么？

型号：

final public class User: ResponseObjectSerializable {
    let username: String
    let name: String

    public init?(response: NSHTTPURLResponse, representation: AnyObject) {
        self.username = representation.valueForKeyPath("username") as! String
        self.name = representation.valueForKeyPath("name") as! String
    }
}

Alamofire请求延期：

import Foundation
import Alamofire

public protocol ResponseObjectSerializable {
    init?(response: NSHTTPURLResponse, representation: AnyObject)
}

extension Request {
    public func responseObject<T: ResponseObjectSerializable>(completionHandler: Response<T, NSError> -> Void) -> Self {
        let responseSerializer = ResponseSerializer<T, NSError> { request, response, data, error in
            guard error == nil else { return .Failure(error!) }

            let JSONResponseSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
            let result = JSONResponseSerializer.serializeResponse(request, response, data, error)

            switch result {
            case .Success(let value):
                if let
                response = response,
                responseObject = T(response: response, representation: value)
                {
                    return .Success(responseObject)
                } else {
                    let failureReason = "JSON could not be serialized into response object: \(value)"
                    let error = Error.errorWithCode(.JSONSerializationFailed, failureReason: failureReason)
                    return .Failure(error)
                }
            case .Failure(let error):
                return .Failure(error)
            }
        }

        return response(responseSerializer: responseSerializer, completionHandler: completionHandler)
    }
}

客户请求：

Alamofire.request(.GET, requestUrl, parameters: params, encoding: .URL)
        .validate()
        .responseObject { (response: Response<User, NSError>) in
          switch response.result {
            case .Success(let user):

                completionHandler(user, nil)

          case .Failure(let error):
                print("Request failed with error: \(error)")

                completionHandler(nil, error)
            }
        }
        return self

Answer 1

您的User课程中有一个可用的初始化程序，但您似乎没有使用它。

这是我想到的简单版本：

class User {
let firstName: String

init?(name: String?) {
    guard let name = name else {
        self.firstName = "" // trash value needed until swift 2.2
        return nil
    }
    self.firstName = name
}
}

Alamofire - 将通用响应对象序列化为JSON模型而不强制解包

1 个答案: