字符串 urlsession 响应未正确处理

Question

我是 swift 的初学者，我创建了 post URLSession，我想从中获取字符串响应，如果我得到“EXIST”，则表示用户存在，我会显示警报，如果我得到“确定”，则相反。我想做的是以那种方式处理这种反应，我在操场上看到像这样的响应“存在”或“确定”但是当我想比较它时它不起作用并且我的警报 none 被执行

//这里是我的函数

 @IBAction func register(_ sender: Any) {

        
        print("hello")
          if(txtPassword.text != txtPasswordrepeat.text) {
              
              let alert = UIAlertController(title: "Register Failed", message: "Passwords Mismatch", preferredStyle: .alert)
              alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil))
              alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
              self.present(alert, animated: true)
            print("passwords mismatch")
              
          }else {
          
          //post
      
          guard let url = URL(string: "http://localhost:3000/register/") else {
          return
          }
          
          let bodyparameters = ["name": txtName.text,"lastname": txtLastname.text, "phone": txtPhone.text,"email": txtEmail.text, "password": txtPassword.text]
         
          var request = URLRequest(url: url)
          request.httpMethod = "POST"
          request.addValue("application/json", forHTTPHeaderField: "Content-Type")
          guard let httpBody = try? JSONSerialization.data(withJSONObject: bodyparameters, options: []) else{
              return
              }
          request.httpBody = httpBody
          let session = URLSession.shared
          session.dataTask(with: request) { (data,response,error) in
              if let response = response {
                  print(response)
              }
              
            if let data = data , let dataString = String(data: data, encoding: String.Encoding.utf8){
                 
                      print(data)
                      
                      DispatchQueue.main.async {
                          
                          
                        let string = dataString as! String
                        print(string)
                        if(string.elementsEqual("EXIST") == true  ){
                             
                              let alert = UIAlertController(title: "Register Failed", message: "User Already Exist", preferredStyle: .alert)
                              alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil))
                              alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
                              self.present(alert, animated: true)
                            
                              
                          }else if(string.elementsEqual("OK") == true){
                          
                              let alert = UIAlertController(title: "Register Successful", message: "User Registred", preferredStyle: .alert)
                              alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil))
                              alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
                              self.present(alert, animated: true)
                              
                          }
                      
                      }
                                   
              }
              
          }.resume()
          
          }
        
    }

//播放地面响应

 2020-12-12 14:06:55.285299-0800 Bicycall[25347:386347] [] nw_protocol_get_quic_image_block_invoke dlopen libquic failed
    <NSHTTPURLResponse: 0x6000036f0140> { URL: http://localhost:3000/login } { Status Code: 200, Headers {
        Connection =     (
            "keep-alive"
        );
        "Content-Length" =     (
            74
        );
        "Content-Type" =     (
            "application/json; charset=utf-8"
        );
        Date =     (
            "Sat, 12 Dec 2020 22:06:55 GMT"
        );
        Etag =     (
            "W/\"4a-yeGoMwACtIYJqSJyS6bmKwCePsk\""
        );
        "Keep-Alive" =     (
            "timeout=5"
        );
        "X-Powered-By" =     (
            Express
        );
    } }
    74 bytes
    21
    
    INSERT SUCCESSFULLY
    21
    hello
    <NSHTTPURLResponse: 0x6000036fa6c0> { URL: http://localhost:3000/register/ } { Status Code: 200, Headers {
        Connection =     (
            "keep-alive"
        );
        "Content-Length" =     (
            7
        );
        "Content-Type" =     (
            "application/json; charset=utf-8"
        );
        Date =     (
            "Sat, 12 Dec 2020 22:07:04 GMT"
        );
        Etag =     (
            "W/\"7-cf+VCoacHzeb2ZclL0nsiKzxBq4\""
        );
        "Keep-Alive" =     (
            "timeout=5"
        );
        "X-Powered-By" =     (
            Express
        );
    } }
    7 bytes
    "EXIST"
    hello
    <NSHTTPURLResponse: 0x6000036e7bc0> { URL: http://localhost:3000/register/ } { Status Code: 200, Headers {
        Connection =     (
            "keep-alive"
        );
        "Content-Length" =     (
            7
        );
        "Content-Type" =     (
            "application/json; charset=utf-8"
        );
        Date =     (
            "Sat, 12 Dec 2020 22:07:06 GMT"
        );
        Etag =     (
            "W/\"7-cf+VCoacHzeb2ZclL0nsiKzxBq4\""
        );
        "Keep-Alive" =     (
            "timeout=5"
        );
        "X-Powered-By" =     (
            Express
        );
    } }
    7 bytes
    "EXIST"
    hello
    <NSHTTPURLResponse: 0x6000036ebcc0> { URL: http://localhost:3000/register/ } { Status Code: 200, Headers {
        Connection =     (
            "keep-alive"
        );
        "Content-Length" =     (
            7
        );
        "Content-Type" =     (
            "application/json; charset=utf-8"
        );
        Date =     (
            "Sat, 12 Dec 2020 22:07:07 GMT"
        );
        Etag =     (
            "W/\"7-cf+VCoacHzeb2ZclL0nsiKzxBq4\""
        );
        "Keep-Alive" =     (
            "timeout=5"
        );
        "X-Powered-By" =     (
            Express
        );
    } }
    7 bytes
    "EXIST"

我想知道我在这里遗漏了什么

Answer 1

欢迎来到 SO 和 Swift！

您的服务器正在发送 "EXIST"，但您正在检查 EXIST。

IOW，而不是 string.elementsEqual("EXIST") == true，试试 string.elementsEqual("\"EXIST\"") == true。

但不要就此止步。将表达式简化为 string == "\"EXIST\"".

字符串 urlsession 响应未正确处理

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