可用于 API 请求的编码

Question

我如何通过可编码来发出相同的 API 请求？ 在我的应用中，这个函数在每个调用 API 的视图中重复。

func getOrders() {

        DispatchQueue.main.async {

            let spinningHUD = MBProgressHUD.showAdded(to: self.view, animated: true)
            spinningHUD.isUserInteractionEnabled = false

            let returnAccessToken: String? = UserDefaults.standard.object(forKey: "accessToken") as? String

            let access  = returnAccessToken!
            let headers = [
                "postman-token": "dded3e97-77a5-5632-93b7-dec77d26ba99",
                "Authorization": "JWT \(access)"
            ]

            let request = NSMutableURLRequest(url: NSURL(string: "https://somelink.com")! as URL,
                                              cachePolicy: .useProtocolCachePolicy,
                                              timeoutInterval: 10.0)

            request.httpMethod          = "GET"
            request.allHTTPHeaderFields = headers

            let session  = URLSession.shared
            let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
                if (error != nil) {
                    print(error!)

                } else {
                    if let dataNew = data, let responseString = String(data: dataNew, encoding: .utf8) {
                        print("----- Orders -----")
                        print(responseString)
                        print("----------")

                        let dict = self.convertToDictionary(text: responseString)
                        print(dict?["results"] as Any)
                        guard let results = dict?["results"] as? NSArray else { return }
                        self.responseArray = (results) as! [HomeVCDataSource.JSONDictionary]

                        DispatchQueue.main.async {
                            spinningHUD.hide(animated: true)
                            self.tableView.reloadData()
                        }

                    }

                }

            })

            dataTask.resume()
        }
    }

Answer 1

我建议做以下事情

1. 如下创建基础服务

import UIKit
import Foundation

enum MethodType: String {
    case get     = "GET"
    case post    = "POST"
    case put     = "PUT"
    case patch   = "PATCH"
    case delete  = "DELETE"
}

class BaseService {

    var session: URLSession!

    // MARK: Rebuilt Methods
    func FireGenericRequest<ResponseModel: Codable>(url: String, methodType: MethodType, headers: [String: String]?, completion: @escaping ((ResponseModel?) -> Void)) {
        UIApplication.shared.isNetworkActivityIndicatorVisible = true

        // Request Preparation
        guard let serviceUrl = URL(string: url) else {
            print("Error Building URL Object")
            return
        }
        var request = URLRequest(url: serviceUrl)
        request.httpMethod = methodType.rawValue

        // Header Preparation
        if let header = headers {
            for (key, value) in header {
                request.setValue(value, forHTTPHeaderField: key)
            }
        }

        // Firing the request
        session = URLSession(configuration: URLSessionConfiguration.default)
        session.dataTask(with: request) { (data, response, error) in
            DispatchQueue.main.async {
                UIApplication.shared.isNetworkActivityIndicatorVisible = false
            }
            if let data = data {
                do {
                    guard let object = try? JSONDecoder().decode(ResponseModel.self , from: data) else {
                        print("Error Decoding Response Model Object")
                        return
                    }
                    DispatchQueue.main.async {
                        completion(object)
                    }
                }
            }
        }.resume()
    }

    private func buildGenericParameterFrom<RequestModel: Codable>(model: RequestModel?) -> [String : AnyObject]? {
        var object: [String : AnyObject] = [String : AnyObject]()
        do {
            if let dataFromObject = try? JSONEncoder().encode(model) {
                object = try JSONSerialization.jsonObject(with: dataFromObject, options: []) as! [String : AnyObject]
            }
        } catch (let error) {
            print("\nError Encoding Parameter Model Object \n \(error.localizedDescription)\n")
        }
        return object
    }

}

上面的类你可以在不同的场景中重用它，向它添加请求对象并传递你想要的任何类，只要你符合 Coddle 协议

1. 创建符合 Coddle 协议的模型

class ExampleModel: Codable {
    var commentId : String?
    var content : String?

    //if your JSON keys are different than your property name
    enum CodingKeys: String, CodingKey {
        case commentId = "CommentId" 
        case content = "Content"
    }

}

1. 使用端点常量子类化到 BaseService 的特定模型创建服务，如下所示

class ExampleModelService: BaseService<ExampleModel/* or [ExampleModel]*/> {

    func GetExampleModelList(completion: ((ExampleModel?)/* or [ExampleModel]*/ -> Void)?) {
        super.FireRequestWithURLSession(url: /* url here */, methodType: /* method type here */, headers: /* headers here */) { (responseModel) in
            completion?(responseModel)
        }
    }

}

• 用法

class MyLocationsController: UIViewController {

    // MARK: Properties
    // better to have in base class for the controller
    var exampleModelService: ExampleModelService = ExampleModelService()

    // MARK: Life Cycle Methods
    override func viewDidLoad() {
        super.viewDidLoad()
        exampleModelService.GetExampleModelList(completion: { [weak self] (response) in
            // model available here
        })
    }
}

Answer 2

基本上，您需要在模型类中遵守Codable 协议，为此您需要实现两种方法，一种用于编码您的模型，另一种用于从JSON 解码您的模型

func encode(to encoder: Encoder) throws

required convenience init(from decoder: Decoder) throws

之后，您将能够使用 Apple 提供的 JSONDecoder 类来解码您的 JSON，并返回一个数组（如果是这样的话）或您的模型类的一个对象。

class ExampleModel: Codable {
    var commentId : String?
    var content : String?

    //if your JSON keys are different than your property name
    enum CodingKeys: String, CodingKey {
        case commentId = "CommentId" 
        case content = "Content"
    }

}

然后使用JSONDecoder 你可以像这样得到你的模型数组

do {
    var arrayOfOrders : [ExampleModel] = try JSONDecoder().decode([ExampleModel].self, from: dataNew)                           
    }
    catch {
    }

Answer 3

首先，我可以建议您使用此应用程序 -quicktype- 将 json 文件转换为您想要的类或结构（可编码）。 enter link description here.

之后，您可以创建一个通用函数来获取任何类型的可编码类并将其作为响应返回。

func taskHandler<T:Codable>(type: T.Type, useCache: Bool, urlRequest: URLRequest, completion: @escaping (Result<T, Error>) -> Void) {
    let task = URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
        if let error = error {
            print("error : \(error)")
        }
        if let data = data {
            do {
                let dataDecoded = try JSONDecoder().decode(T.self, from: data)
                completion(.success(dataDecoded))
                // if says use cache, let's store response data to cache
                if useCache {
                    if let response = response as? HTTPURLResponse {
                        self.storeDataToCache(urlResponse: response, urlRequest: urlRequest, data: data)
                    }
                }
            } catch let error {
                completion(.failure(error))
            }
        } else {
            completion(.failure(SomeError))
        }
    }
    task.resume()
}