ios - 如何在 Swift 中执行 GET 和 POST 请求？

Question

我改编自 Ray Wenderlich 的 iOS Apprentice 教程第 4 部分。

此代码作为 GET 请求使用简单的数据库模型发送到我的 Strongloop API，但是:

1. 这行得通，但我不知道它为什么行得通，因为它没有调用任何我能看到的实际发送请求的方法。

2. 我认为没有办法将其变成 POST 请求。

我的问题是:如何执行 POST 请求？它是以完全不同的方式完成的吗？

如果您需要更多信息，请告诉我。

    class ViewController: UIViewController {


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

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func getFromDB() {
        let url = urlWithSearchText("")
        println("URL: '\(url)'")
        if let jsonString = performGetRequestWithURL(url) {
            println("Received JSON string '\(jsonString)'")
        }
    }


    func urlWithSearchText(searchText: String) -> NSURL {
        let escapedSearchText = searchText.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!
        let urlString = String(format: "http://localhost:3000/api/Tests", escapedSearchText)
        let url = NSURL(string: urlString)
        return url!
    }    

    func performGetRequestWithURL(url: NSURL) -> String? {
        var error: NSError?
        if let resultString = String(contentsOfURL: url, encoding: NSUTF8StringEncoding, error: &error) {
            return resultString
        } else if let error = error {
            println("Download Error: \(error)")
        } else {
            println("Unknown Download Error")
        }
        return nil
    }

这是工作的图片:

https://dl.dropboxusercontent.com/u/14464971/Images/Messages%20Image%281477993527%29.png

Answer 1

Swift 3 及更高版本

获取

 func getRequest() {
    
    // request url
    let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")! // change the url
    
    // create URLSession with default configuration
    let session = URLSession.shared
    
    // create dataTask using the session object to send data to the server
    let task = session.dataTask(with: url) { data, response, error in
        
        if let error = error {
            print("GET Request Error: \(error.localizedDescription)")
            return
        }
        
        // ensure there is valid response code returned from this HTTP response
        guard let httpResponse = response as? HTTPURLResponse,
              (200...299).contains(httpResponse.statusCode) else {
                  print("Invalid Response received from the server")
                  return
              }
        
        // ensure there is data returned
        guard let responseData = data else {
            print("nil Data received from the server")
            return
        }
        
        do {
            // serialise the data object into Dictionary [String : Any]
            if let jsonResponse = try JSONSerialization.jsonObject(with: responseData, options: .mutableContainers) as? [String: Any] {
                print(jsonResponse)
            } else {
                print("data maybe corrupted or in wrong format")
                throw URLError(.badServerResponse)
            }
        } catch let error {
            print("JSON Parsing Error: \(error.localizedDescription)")
        }
    }
    // resume the task
    task.resume()
}

发布

func postRequest() {
    
    // declare the parameter as a dictionary that contains string as key and value combination. considering inputs are valid
    
    let parameters: [String: Any] = ["name": "abc", "password": "password@123"]
    
    // create the url with URL
    let url = URL(string: "http://myServerName.com/api")! //change the url
    
    // create the session object
    let session = URLSession.shared
    
    // now create the URLRequest object using the url object
    var request = URLRequest(url: url)
    request.httpMethod = "POST" //set http method as POST
    
    // add headers for the request
    request.addValue("application/json", forHTTPHeaderField: "Content-Type") // change as per server requirements
    request.addValue("application/json", forHTTPHeaderField: "Accept")
    
    do {
        // convert parameters to Data and assign dictionary to httpBody of request
        request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: .prettyPrinted)
    } catch let error {
        print(error.localizedDescription)
        return
    }
    
    // create dataTask using the session object to send data to the server
    let task = session.dataTask(with: request) { data, response, error in
        
        if let error = error {
            print("Post Request Error: \(error.localizedDescription)")
            return
        }
        
        // ensure there is valid response code returned from this HTTP response
        guard let httpResponse = response as? HTTPURLResponse,
              (200...299).contains(httpResponse.statusCode)
        else {
            print("Invalid Response received from the server")
            return
        }
        
        // ensure there is data returned
        guard let responseData = data else {
            print("nil Data received from the server")
            return
        }
        
        do {
            // create json object from data or use JSONDecoder to convert to Model stuct
            if let jsonResponse = try JSONSerialization.jsonObject(with: responseData, options: .mutableContainers) as? [String: Any] {
                print(jsonResponse)
                // handle json response
            } else {
                print("data maybe corrupted or in wrong format")
                throw URLError(.badServerResponse)
            }
        } catch let error {
            print(error.localizedDescription)
        }
    }
    task.resume()
}