ios 如何从 Alamofire 返回值

How to return value from Alamofire

提问by u54r

I am making url calls thru an API that I created using swift as follows:

我正在通过我使用 swift 创建的 API 进行 url 调用，如下所示：

class API {

  let apiEndPoint = "endpoint"
  let apiUrl:String!
  let consumerKey:String!
  let consumerSecret:String!

  var returnData = [:]

  init(){
    self.apiUrl = "https://myurl.com/"
    self.consumerKey = "my consumer key"
    self.consumerSecret = "my consumer secret"
  }

  func getOrders() -> NSDictionary{
    return makeCall("orders")
  }

  func makeCall(section:String) -> NSDictionary{

    let params = ["consumer_key":"key", "consumer_secret":"secret"]

    Alamofire.request(.GET, "\(self.apiUrl)/\(self.apiEndPoint + section)", parameters: params)
        .authenticate(user: self.consumerKey, password: self.consumerSecret)
        .responseJSON { (request, response, data, error) -> Void in
            println("error \(request)")
            self.returnData = data! as NSDictionary
    }
    return self.returnData
  }

}

I call this API in my UITableViewControllerto populate the table with SwiftyJSON library. However my returnDatafrom the API is always empty. There is no problem with Alomofire calls as I can successfully retrieve value. My problem is how I am supposed to carry this dataover to my table view controller?

我在 my 中调用此 API 以UITableViewController使用 SwiftyJSON 库填充表。但是我returnData从 API 总是空的。Alomofire 调用没有问题，因为我可以成功检索值。我的问题是我应该如何将它data传递给我的表视图控制器？

var api = API()
api.getOrders()
println(api.returnData) // returnData is empty

回答by Rob

As mattt points out, Alamofire is returning data asynchronously via a “completion handler” pattern, so you must do the same. You cannot just returnthe value immediately, but you instead want to change your method to not return anything, but instead use a completion handler closure pattern.

正如马特指出的那样，Alamofire 通过“完成处理程序”模式异步返回数据，因此您必须这样做。您不能return立即使用该值，而是希望将方法更改为不返回任何内容，而是使用完成处理程序关闭模式。

Nowadays, that might look like:

如今，这可能看起来像：

func getOrders(completionHandler: @escaping (Result<[String: Any]>) -> Void) {
    performRequest("orders", completion: completionHandler)
}

func performRequest(_ section: String, completion: @escaping (Result<[String: Any]>) -> Void) {
    let url = baseURL.appendingPathComponent(section)
    let params = ["consumer_key": "key", "consumer_secret": "secret"]

    Alamofire.request(url, parameters: params)
        .authenticate(user: consumerKey, password: consumerSecret)
        .responseJSON { response in
            switch response.result {
            case .success(let value as [String: Any]):
                completion(.success(value))

            case .failure(let error):
                completion(.failure(error))

            default:
                fatalError("received non-dictionary JSON response")
            }
    }
}

Then, when you want to call it, you use this completionclosure parameter (in trailing closure, if you want):

然后，当你想调用它时，你可以使用这个completion闭包参数（在尾随闭包中，如果你想要的话）：

api.getOrders { result in
    switch result {
    case .failure(let error):
        print(error)

    case .success(let value):
        // use `value` here
    }
}

// but don't try to use the `error` or `value`, as the above closure
// has not yet been called
//

回答by mattt

From the Alamofire README (emphasis added):

来自 Alamofire README（强调已添加）：

Networking in Alamofire is done asynchronously. Asynchronous programming may be a source of frustration to programmers unfamiliar with the concept, but there are very good reasons for doing it this way.

Rather than blocking execution to wait for a response from the server, a callback is specified to handle the response once it's received. The result of a request is only available inside the scope of a response handler. Any execution contingent on the response or data received from the server must be done within a handler.

Alamofire 中的网络是异步完成的。异步编程可能会让不熟悉这个概念的程序员感到沮丧，但这样做是有充分理由的。

不是阻塞执行以等待来自服务器的响应，而是指定一个回调来处理接收到的响应。请求的结果仅在响应处理程序的范围内可用。任何取决于从服务器接收到的响应或数据的执行都必须在处理程序中完成。

回答by n.by.n

Following is the complete flow for performing the 'Login Action'using Alamofire and Swift.

以下是使用 Alamofire 和 Swift执行“登录操作”的完整流程。

Alamofire v3.3 Swift 2.2 Xcode 7.3

Alamofire v3.3 Swift 2.2 Xcode 7.3

I have used GCDand MBProgressHUDfor my own convenience. Refactor and use as you like :)

为了方便起见，我使用了GCD和MBProgressHUD。重构和使用你喜欢:)

func loginBtnTapped(sender: AnyObject) {

    MBProgressHUD.showHUDAddedTo(self.view, animated: true)

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {

        let loginInfo : Dictionary<String,AnyObject> = ["email":"[email protected]","password":"abc123"]

        self.loginUser(loginInfo) { responseObject, error in

            print("\(responseObject) \n  \(error) ")

            // Parsing JSON Below
            let status = Int(responseObject?.objectForKey("status") as! String)
            if status == 1 {
                // Login Successfull...Move To New VC
            }
            else {
                print(responseObject?.objectForKey("message"))! as! String)
            }
            return
        }
        dispatch_async(dispatch_get_main_queue()) {
            MBProgressHUD.hideHUDForView(self.view, animated: true)
        }
    }

}


func loginUser(parameters:NSDictionary, completionHandler: (NSDictionary?, NSError?) -> ()) {

    self.postRequest("http://qa.company.com/project/index.php/user/login",
                     paramDict: parameters as? Dictionary<String, AnyObject>,
                     completionHandler: completionHandler)
}

func postRequest(urlString: String, paramDict:Dictionary<String, AnyObject>? = nil,
                 completionHandler: (NSDictionary?, NSError?) -> ()) {

    Alamofire.request(.POST, urlString, parameters: paramDict)
        .responseJSON { response in
            switch response.result {
            case .Success(let JSON):
                completionHandler(JSON as? NSDictionary, nil)
            case .Failure(let error):
                completionHandler(nil, error)
            }
    }

}

回答by Vasily Bodnarchuk

Details

细节

xCode 9.1, Swift 4

xCode 9.1，斯威夫特 4

Features:

特征：

• Easy readable code
• Ready templates (it's easy to add more requests)
• Embedded solution with asynchronous data processing
• Full examples

• 易读的代码
• 准备好的模板（很容易添加更多请求）
• 具有异步数据处理的嵌入式解决方案
• 完整示例

Sample 1

示例 1

Return data using closure

使用闭包返回数据

Data1.searchRequest(term: "Hyman johnson") { json, error  in
     print(error ?? "nil")
     print(json ?? "nil")
     print("Update views")
}

Full sample 1

完整样本 1

Data class

数据类

import Alamofire

class Data1 {

    static fileprivate let queue = DispatchQueue(label: "requests.queue", qos: .utility)
    static fileprivate let mainQueue = DispatchQueue.main

    fileprivate class func make(request: DataRequest, closure: @escaping (_ json: [String: Any]?, _ error: Error?)->()) {
        request.responseJSON(queue: Data1.queue) { response in

            // print(response.request ?? "nil")  // original URL request
            // print(response.response ?? "nil") // HTTP URL response
            // print(response.data ?? "nil")     // server data
            //print(response.result ?? "nil")   // result of response serialization

            switch response.result {
            case .failure(let error):
                Data1.mainQueue.async {
                    closure(nil, error)
                }

            case .success(let data):
                Data1.mainQueue.async {
                    closure((data as? [String: Any]) ?? [:], nil)
                }
            }
        }
    }

    class func searchRequest(term: String, closure: @escaping (_ json: [String: Any]?, _ error: Error?)->()) {
        let request = Alamofire.request("https://itunes.apple.com/search?term=\(term.replacingOccurrences(of: " ", with: "+"))")
        Data1.make(request: request) { json, error in
            closure(json, error)
        }
    }
}

UIViewController

视图控制器

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        Data1.searchRequest(term: "Hyman johnson") { json, error  in
            print(error ?? "nil")
            print(json ?? "nil")
            print("Update views")
        }
    }
}

---

---

Sample 2

样本 2

Return data using delegate

使用委托返回数据

// ....
var data = Data2()
data.delegate = self
data.searchRequest(term: "Hyman johnson")
// ....

extension ViewController: Data2Delegate {
    func searchRequest(response json: [String : Any]?, error: Error?) {
        print(error ?? "nil")
        print(json ?? "nil")
        print("Update views")
    }
}

Full sample 2

完整样本 2

Data class

数据类

import Alamofire

protocol Data2Delegate: class {
    func searchRequest(response json: [String: Any]?, error: Error?)
}

class Data2 {

    fileprivate let queue = DispatchQueue(label: "requests.queue", qos: .utility)
    fileprivate let mainQueue = DispatchQueue.main

    weak var delegate: Data2Delegate?

    fileprivate func make(request: DataRequest, closure: @escaping (_ json: [String: Any]?, _ error: Error?)->()) {
        request.responseJSON(queue: queue) { response in

            // print(response.request ?? "nil")  // original URL request
            // print(response.response ?? "nil") // HTTP URL response
            // print(response.data ?? "nil")     // server data
            //print(response.result ?? "nil")   // result of response serialization

            switch response.result {
            case .failure(let error):
                self.mainQueue.async {
                    closure(nil, error)
                }

            case .success(let data):
                self.mainQueue.async {
                    closure((data as? [String: Any]) ?? [:], nil)
                }
            }
        }
    }

    func searchRequest(term: String) {
        let request = Alamofire.request("https://itunes.apple.com/search?term=\(term.replacingOccurrences(of: " ", with: "+"))")
        make(request: request) { json, error in
            self.delegate?.searchRequest(response: json, error: error)
        }
    }
}

UIViewController

视图控制器

import UIKit

class ViewController: UIViewController {
    private var data = Data2()
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        data.delegate = self
        data.searchRequest(term: "Hyman johnson")
    }
}

extension ViewController: Data2Delegate {
    func searchRequest(response json: [String : Any]?, error: Error?) {
        print(error ?? "nil")
        print(json ?? "nil")
        print("Update views")
    }
}

Sample 3

示例 3

Return data using PromiseKit

使用PromiseKit返回数据

_ = data.searchRequest(term: "Hyman johnson").then { response in
      print(response.error ?? "nil")
      print(response.json ?? "nil")
      print("Update views")
      return .void
}

Full sample 3

完整样本 3

Data class import Alamofire import PromiseKit

数据类导入 Alamofire 导入 PromiseKit

class Data3 {

    fileprivate let queue = DispatchQueue(label: "requests.queue", qos: .utility)
    fileprivate let mainQueue = DispatchQueue.main

    fileprivate func make(request: DataRequest) -> Promise<(json:[String: Any]?, error: Error?)> {
         return Promise { fulfill, reject in
            request.responseJSON(queue: queue) { response in

                // print(response.request ?? "nil")  // original URL request
                // print(response.response ?? "nil") // HTTP URL response
                // print(response.data ?? "nil")     // server data
                //print(response.result ?? "nil")   // result of response serialization

                switch response.result {
                    case .failure(let error):
                        self.mainQueue.async {
                            fulfill((nil, error))
                        }

                    case .success(let data):
                        self.mainQueue.async {
                            fulfill(((data as? [String: Any]) ?? [:], nil))
                        }
                }
            }
        }
    }

    func searchRequest(term: String) -> Promise<(json:[String: Any]?, error: Error?)> {
        let request = Alamofire.request("https://itunes.apple.com/search?term=\(term.replacingOccurrences(of: " ", with: "+"))")
        return make(request: request)
    }
}

extension AnyPromise {

    class var void: AnyPromise {
        return AnyPromise(Promise<Void>())
    }
}

UIViewController

视图控制器

import UIKit
import PromiseKit

class ViewController: UIViewController {
    private var data = Data3()
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        _ = data.searchRequest(term: "Hyman johnson").then { response in
            print(response.error ?? "nil")
            print(response.json ?? "nil")
            print("Update views")
            return .void
        }
    }
}

回答by kishorer747

To parse a json using Swifty JSON, here is how i am doing it.

For @Jenita _Alice4Real

要使用 Swifty JSON 解析 json，这是我的做法。

对于@Jenita _Alice4Real

func uploadScans(parameters: [String: AnyObject], completionHandler: (AnyObject?, NSError?) -> ()) {
    makePostCall(CommonFunctions().getSaveSKUDataUrl(), parameters: parameters,completionHandler: completionHandler)
}

func makePostCall(url: String, parameters: [String: AnyObject], completionHandler: (AnyObject?, NSError?) -> ()) {
    Alamofire.request(.POST, url, parameters: parameters)
        .responseJSON { response in
            switch response.result {
                case .Success(let value):
                    completionHandler(value, nil)
                case .Failure(let error):
                    completionHandler(nil, error)
            }
    }
}

uploadScans(params) { responseObject, error in
    let json = JSON(responseObject!)
}