Swift-4：如何使用带有“Content-Type”的 URLSession 参数的 POST 请求获取数据：“application/x-www-form-urlencoded”

Question

朋友们，我已经经历了很多示例，这些示例都可以在 SO 上找到，尽管我没有收到正确的答案，但我仍然面临着使用 URLSession 和 Post 请求并通过它传递参数通过 api 请求获取数据的问题。

首先，我想告诉你，我有什么。 试到现在...

func requestApiCall(){

    let renewal_id = ""
    let policy_no = ""
    let client_name = ""
    let client_id = ""
    let product_name = ""
    let created_date_from = ""
    let created_date_to = ""
    let policy_expiry_from = ""
    let policy_expiry_to = ""

    self.parameters = ["renewal_id":renewal_id,"policy_no":policy_no,"client_name":client_name,"client_id":client_id,"product_name":product_name,"created_date_from":created_date_from,"created_date_to":created_date_to,"policy_expiry_from":policy_expiry_from,"policy_expiry_to":policy_expiry_to]

    let config = URLSessionConfiguration.default
    config.httpAdditionalHeaders = [
        "Accept" : "application/json",
        "Content-Type" : "application/x-www-form-urlencoded"
    ]
    let session = URLSession(configuration: config)
    let Url = String(format: "http://myapi-url");
    let serviceUrl = URL(string: Url)
    var request = URLRequest(url: serviceUrl!)
    print(request.url!)
    request.httpMethod = "POST"
    request.timeoutInterval = 60

    request.httpBody  = try! JSONSerialization.data(withJSONObject: parameters!, options: [])

    let task = session.dataTask(with: request as URLRequest, completionHandler: {data, response, error -> Void in

        if error == nil{
            print(response!)
        }
        else {
            print(error?.localizedDescription as Any)
        }

        print(response!)
        guard let httpResponse = response as? HTTPURLResponse, let receivedData = data
            else {
                print("error: not a valid http response")
                return
        }

        switch (httpResponse.statusCode)
        {
        case 200: //The request was fulfilled
            let response = NSString (data: receivedData, encoding: String.Encoding.utf8.rawValue)

            if response == "SUCCESS"
            {
                print("Network - HandShaking Successfull...!!!")
            }
            else{
                print("Network - HandShaking is not successfull...!!!")
            }

        case 400:
            print("response-status - 400 : The request had bad syntax or was inherently impossible to be satisfied.")
        case 500:
            print("\nresponse-status - 500 : Internal Server Error...!!!")
        default:
            print("response-status - Unknown : Received Response =>  \(httpResponse.statusCode)")
        }
    })
    task.resume()
}

运行上述函数后，我得到 httpResponse.statusCode = 500

但是当我在邮递员中运行它时，我得到了正确的响应，就像方面一样。

Postman API 请求

我也尝试通过邮递员生成代码片段......如下......

func postmanSnippetApiCall(){
    let headers = [
        "Content-Type": "application/x-www-form-urlencoded",
        "cache-control": "no-cache",
        "Postman-Token": "5d571157-86c5-4eac-ba6d-b00779ae5dbd"
    ]

    let postData = NSMutableData(data: "renewal_id=".data(using: String.Encoding.utf8)!)
    postData.append("&policy_no=".data(using: String.Encoding.utf8)!)
    postData.append("&client_name=".data(using: String.Encoding.utf8)!)
    postData.append("&client_id=".data(using: String.Encoding.utf8)!)
    postData.append("&product_name=".data(using: String.Encoding.utf8)!)
    postData.append("&created_date_from=".data(using: String.Encoding.utf8)!)
    postData.append("&created_date_to=".data(using: String.Encoding.utf8)!)
    postData.append("&policy_expiry_from=".data(using: String.Encoding.utf8)!)
    postData.append("&policy_expiry_to=".data(using: String.Encoding.utf8)!)
    postData.append("&undefined=undefined".data(using: String.Encoding.utf8)!)

    let request = NSMutableURLRequest(url: NSURL(string: "http://myapiurl")! as URL,
                                      cachePolicy: .useProtocolCachePolicy,
                                      timeoutInterval: 10.0)
    request.httpMethod = "POST"
    request.allHTTPHeaderFields = headers
    request.httpBody = postData as Data

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

    dataTask.resume()
}

但是在邮递员生成的代码片段中，我在这一行收到错误，即request.httpBody = postData as Data错误是这个： Cannot convert value of type 'NSMutableData' to type 'Data' in coercion

如果我使用第三方库，即Alamofire ，那么我能够非常轻松地获取数据。

Alamofire 代码片段...运行完美...& 给出了正确的响应。

func apiRequestByAlamofire(){
        let urlString = "http://myapiurl"

        let params: [String: Any]? = ["renewal_id":"","policy_no":"","client_name":"","client_id":"","product_name":"","created_date_from":"","created_date_to":"","policy_expiry_from":"","policy_expiry_to":""]

        Alamofire.request(urlString, method: .post, parameters: params).responseJSON { response in
            print(response) //Here getting perfect response successfully...!!!
        }

    }

但我仍然在通过 URLSession 苦苦挣扎......！！！

我仍然怀疑，这就是为什么我在使用 URLSession 时遇到太多问题的原因。

以上我的疑问的朋友，请我愿意接受您的建议，并请帮助我理解它。

不知道，我哪里错了。 请帮帮我。

Answer 1

尝试直接在URLRequest添加标头，而不是直接在URLSession添加标头，还尝试使用不同的Content-Type和Accept例如application/json ， application/x-www-form-urlencoded等。

let config = URLSessionConfiguration.default
config.timeoutIntervalForRequest = TimeInterval(30)
config.timeoutIntervalForResource = TimeInterval(30)

let session = URLSession(configuration: config)
let Url = String(format: "http://myapi-url")
let serviceUrl = URL(string: Url)

var request = URLRequest(url: serviceUrl!)
print(request.url!)

request.httpMethod = "POST"

let parameters: [String: Any]? = //Request parameters in Dictionary format like ["user_id": 2, "name": "TestUser"]

//Set body to url request
if parameters != nil {

    do {
        let bodyData = try JSONSerialization.data(withJSONObject: parameters!,
                                                  options: JSONSerialization.WritingOptions.prettyPrinted)
        request.httpBody = bodyData
    } catch let error {
        print(error.localizedDescription)
    }
}

request.addValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type") //Try different types of Content-Types here like "application/json", etc.
request.addValue("application/json", forHTTPHeaderField: "Accept") //Try different types of Content-Types here like "application/json", etc.

let task = session.dataTask(with: request) { (data, response, error) in

    // Your code here
    guard data != nil && error == nil else {
        return
    }

    let apiResponse = String.init(data: data!, encoding: String.Encoding.utf8)!
    print(apiResponse)
}

task.resume()
session.finishTasksAndInvalidate()

请访问下面的链接，了解如何使用URLSession进行编码。

https://github.com/sateeshyegireddi/MovieFlix/blob/master/MovieFlix/MovieFlix/API/APIHandler.swift

Answer 2

我给你简单的功能，你可以根据你的要求编辑这个功能。 您也可以更改您的 URL 和参数。 在响应中，我写了两行，如果你从服务器获取 JSON 数组，然后使用第一个，如果你正在获取对象，然后第二个删除两行。

func abc()  {
    let request = NSMutableURLRequest(url: URL(string: "Your URL")!)
    request.httpMethod = "POST"
    let postString = "param_name_one=\( value_1 )&param_name_two=\(value_2)&........."
    request.httpBody = postString.data(using: String.Encoding.utf8)
    let task = URLSession.shared.dataTask(with: request as URLRequest) {
        data, response, error in
        if(error != nil){
            // Show Error Message
        } else{
            do {
                //For JSON ARRAY
                let jsonItem  = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSArray
                let json = jsonItem[0] as AnyObject
               //For JSON object 
                let json_object  = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as AnyObject
                print(json_object)
                
            } catch {
                
            }
        }
    }
    task.resume();
}

Answer 3

在对此进行了大量搜索和斗争之后，我提出了以下解决方案：

        guard var components = URLComponents(url: URL(string: "http://example.com")!, resolvingAgainstBaseURL: true)
            else { fatalError("Couldn't create URLComponents") }
        
        components.queryItems = params.map { k, v in URLQueryItem(name: k, value: v) }
        
        var request = URLRequest(url: baseUrl.appendingPathComponent(path.rawValue))
        request.httpBody = Data(components.query!.utf8)
        request.httpMethod = "POST"

“example.com”字面上可以是这样，因为我只是使用URLComponents对参数进行编码。