在 C# 中通过 POST 发送 JSON 并接收返回的 JSON? [英] Send JSON via POST in C# and Receive the JSON returned?

问题描述

这是我第一次在我的任何应用程序中使用 JSON 以及 System.Net 和 WebRequest.我的应用程序应该向身份验证服务器发送一个类似于下面的 JSON 有效负载:

This is my first time ever using JSON as well as System.Net and the WebRequest in any of my applications. My application is supposed to send a JSON payload, similar to the one below to an authentication server:

{
  "agent": {                             
    "name": "Agent Name",                
    "version": 1                                                          
  },
  "username": "Username",                                   
  "password": "User Password",
  "token": "xxxxxx"
}

为了创建这个负载，我使用了 JSON.NET 库.我如何将此数据发送到身份验证服务器并接收其 JSON 响应?这是我在一些示例中看到的，但没有 JSON 内容:

To create this payload, I used the JSON.NET library. How would I send this data to the authentication server and receive its JSON response back? Here is what I have seen in some examples, but no JSON content:

var http = (HttpWebRequest)WebRequest.Create(new Uri(baseUrl));
http.Accept = "application/json";
http.ContentType = "application/json";
http.Method = "POST";

string parsedContent = "Parsed JSON Content needs to go here";
ASCIIEncoding encoding = new ASCIIEncoding();
Byte[] bytes = encoding.GetBytes(parsedContent);

Stream newStream = http.GetRequestStream();
newStream.Write(bytes, 0, bytes.Length);
newStream.Close();

var response = http.GetResponse();

var stream = response.GetResponseStream();
var sr = new StreamReader(stream);
var content = sr.ReadToEnd();

但是，与我过去使用过的其他语言相比，这似乎是很多代码.我这样做正确吗?以及如何获取 JSON 响应以便我可以解析它?

However, this seems to be a lot of code compaired to using other languages I have used in the past. Am I doing this correctly? And how would I get the JSON response back so I can parse it?

谢谢，精英.

更新代码

// Send the POST Request to the Authentication Server
// Error Here
string json = await Task.Run(() => JsonConvert.SerializeObject(createLoginPayload(usernameTextBox.Text, password)));
var httpContent = new StringContent(json, Encoding.UTF8, "application/json");
using (var httpClient = new HttpClient())
{
    // Error here
    var httpResponse = await httpClient.PostAsync("URL HERE", httpContent);
    if (httpResponse.Content != null)
    {
        // Error Here
        var responseContent = await httpResponse.Content.ReadAsStringAsync();
    }
}

推荐答案

我发现自己在使用 HttpClient 库来查询 RESTful API，因为代码非常简单且完全异步.要发送此 JSON 有效负载:

I found myself using the HttpClient library to query RESTful APIs as the code is very straightforward and fully async'ed. To send this JSON payload:

{
  "agent": {                             
    "name": "Agent Name",                
    "version": 1                                                          
  },
  "username": "Username",                                   
  "password": "User Password",
  "token": "xxxxxx"
}

有两个类代表您发布的 JSON 结构，可能如下所示:

With two classes representing the JSON structure you posted that may look like this:

public class Credentials
{
    public Agent Agent { get; set; }
    
    public string Username { get; set; }
    
    public string Password { get; set; }
    
    public string Token { get; set; }
}

public class Agent
{
    public string Name { get; set; }
    
    public int Version { get; set; }
}

您可以使用这样的方法来执行您的 POST 请求:

You could have a method like this, which would do your POST request:

var payload = new Credentials { 
    Agent = new Agent { 
        Name = "Agent Name",
        Version = 1 
    },
    Username = "Username",
    Password = "User Password",
    Token = "xxxxx"
};

// Serialize our concrete class into a JSON String
var stringPayload = JsonConvert.SerializeObject(payload);

// Wrap our JSON inside a StringContent which then can be used by the HttpClient class
var httpContent = new StringContent(stringPayload, Encoding.UTF8, "application/json");

var httpClient = new HttpClient()
    
// Do the actual request and await the response
var httpResponse = await httpClient.PostAsync("http://localhost/api/path", httpContent);

// If the response contains content we want to read it!
if (httpResponse.Content != null) {
    var responseContent = await httpResponse.Content.ReadAsStringAsync();
    
    // From here on you could deserialize the ResponseContent back again to a concrete C# type using Json.Net
}

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