如何在C#中通过POST发送JSON并接收返回的JSON?

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这是我第一次在任何应用程序中使用JSON甚至System.NetWebRequest部分。我的应用程序应该发送一个JSON有效载荷,类似于下面的一个到认证服务器:

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

为了创建这个有效载荷,我使用了JSON.NET库。我如何将这些数据发送到认证服务器并返回其JSON响应?这里是我在一些例子中看到的,但没有JSON内容:

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,这似乎是很多代码比较使用我以前使用的其他语言。我是否正确地做了这件事?我怎么会得到的JSON响应,所以我可以解析它?

// 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();
    }
}
提问于
用户回答回答于

我发现自己使用HttpClient库来查询RESTful API,因为代码非常简单并且完全异步。

有两个类表示您发布的JSON结构,可能如下所示:

public class Credentials
{
    [JsonProperty("agent")]
    public Agent Agent { get; set; }

    [JsonProperty("username")]
    public string Username { get; set; }

    [JsonProperty("password")]
    public string Password { get; set; }

    [JsonProperty("token")]
    public string Token { get; set; }
}

public class Agent
{
    [JsonProperty("name")]
    public string Name { get; set; }

    [JsonProperty("version")]
    public int Version { get; set; }
}

你可以有这样的方法,它会做你的POST请求:

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 = await Task.Run(() => 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");

using (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
    }
}
用户回答回答于

可以HttpContent使用以下组合来构建您的组合:JObject避免并在构建以下对象时JProperty调用ToString()StringContent

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

        JObject payLoad = new JObject(
            new JProperty("agent", 
                new JObject(
                    new JProperty("name", "Agent Name"),
                    new JProperty("version", 1)
                    ),
                new JProperty("username", "Username"),
                new JProperty("password", "User Password"),
                new JProperty("token", "xxxxxx")    
                )
            );

        using (HttpClient client = new HttpClient())
        {
            var httpContent = new StringContent(payLoad.ToString(), Encoding.UTF8, "application/json");

            using (HttpResponseMessage response = await client.PostAsync(requestUri, httpContent))
            {
                response.EnsureSuccessStatusCode();
                string responseBody = await response.Content.ReadAsStringAsync();
                return JObject.Parse(responseBody);
            }
        }

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