如何发出 HTTP POST 网络请求 [英] How to make an HTTP POST web request

问题描述

规范
如何使用 POST 方法发出 HTTP 请求并发送一些数据?

我可以执行 GET 请求，但我不知道如何发出 POST 请求.

I can do a GET request, but I have no idea of how to make a POST request.

推荐答案

有几种方法可以执行 HTTP GET 和 POST 请求:

There are several ways to perform HTTP GET and POST requests:

适用于:.NET Framework 4.5+、.NET Standard 1.1+、.NET Core 1.0+ .

这是目前首选的方法，并且是异步和高性能的.大多数情况下使用内置版本，但对于非常旧的平台，有一个 NuGet 包.

It is currently the preferred approach, and is asynchronous and high performance. Use the built-in version in most cases, but for very old platforms there is a NuGet package.

using System.Net.Http;

设置

建议实例化一个HttpClient 在您的应用程序的生命周期内共享它，除非您有特定的理由不这样做.

Setup

It is recommended to instantiate one HttpClient for your application's lifetime and share it unless you have a specific reason not to.

private static readonly HttpClient client = new HttpClient();

参见 HttpClientFactory 用于 依赖注入解决方案.

• POST

var values = new Dictionary<string, string>
{
    { "thing1", "hello" },
    { "thing2", "world" }
};

var content = new FormUrlEncodedContent(values);

var response = await client.PostAsync("http://www.example.com/recepticle.aspx", content);

var responseString = await response.Content.ReadAsStringAsync();

GET

var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");

RestSharp

• POST

 var client = new RestClient("http://example.com");
 // client.Authenticator = new HttpBasicAuthenticator(username, password);
 var request = new RestRequest("resource/{id}");
 request.AddParameter("thing1", "Hello");
 request.AddParameter("thing2", "world");
 request.AddHeader("header", "value");
 request.AddFile("file", path);
 var response = client.Post(request);
 var content = response.Content; // Raw content as string
 var response2 = client.Post<Person>(request);
 var name = response2.Data.Name;

Flurl.Http

它是一个较新的库，具有流畅的 API、测试助手、在后台使用 HttpClient 并且是可移植的.它可以通过 NuGet 获得.

It is a newer library sporting a fluent API, testing helpers, uses HttpClient under the hood, and is portable. It is available via NuGet.

    using Flurl.Http;

<小时>

• POST

  var responseString = await "http://www.example.com/recepticle.aspx"
      .PostUrlEncodedAsync(new { thing1 = "hello", thing2 = "world" })
      .ReceiveString();
  

• GET

  var responseString = await "http://www.example.com/recepticle.aspx"
      .GetStringAsync();
  

适用于:.NET Framework 1.1+、.NET Standard 2.0+、.NET Core 1.0+.在 .NET Core 中，它主要是为了兼容性——它封装了 HttpClient，性能较低，并且不会获得新功能.

Available in: .NET Framework 1.1+, .NET Standard 2.0+, .NET Core 1.0+. In .NET Core, it is mostly for compatibility -- it wraps HttpClient, is less performant, and won't get new features.

using System.Net;
using System.Text;  // For class Encoding
using System.IO;    // For StreamReader

<小时>

• POST

  var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");
  
  var postData = "thing1=" + Uri.EscapeDataString("hello");
      postData += "&thing2=" + Uri.EscapeDataString("world");
  var data = Encoding.ASCII.GetBytes(postData);
  
  request.Method = "POST";
  request.ContentType = "application/x-www-form-urlencoded";
  request.ContentLength = data.Length;
  
  using (var stream = request.GetRequestStream())
  {
      stream.Write(data, 0, data.Length);
  }
  
  var response = (HttpWebResponse)request.GetResponse();
  
  var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
  

• GET

  var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");
  
  var response = (HttpWebResponse)request.GetResponse();
  
  var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
  

这是对 HttpWebRequest 的封装.与HttpClient比较.

This is a wrapper around HttpWebRequest. Compare with HttpClient.

适用于:.NET Framework 1.1+、NET Standard 2.0+、.NET Core 2.0+

using System.Net;
using System.Collections.Specialized;

<小时>

• POST

  using (var client = new WebClient())
  {
      var values = new NameValueCollection();
      values["thing1"] = "hello";
      values["thing2"] = "world";
  
      var response = client.UploadValues("http://www.example.com/recepticle.aspx", values);
  
      var responseString = Encoding.Default.GetString(response);
  }
  

• GET

  using (var client = new WebClient())
  {
      var responseString = client.DownloadString("http://www.example.com/recepticle.aspx");
  }
  

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