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C# HTTP请求 GET&POST

什么是 HTTP ？

　　超文本传输协议（HTTP）的设计目的是保证客户端与服务器之间的通信。

　　HTTP 的工作方式是客户端与服务器之间的请求-应答协议。

　　web 浏览器可能是客户端，而计算机上的网络应用程序也可能作为服务器端。

　　举例：客户端（浏览器）向服务器提交 HTTP 请求；服务器向客户端返回响应。响应包含关于请求的状态信息以及可能被请求的内容。

　　两种最常用的 HTTP 方法是：GET 和 POST。

GET - 从指定的资源请求数据。
POST - 向指定的资源提交要被处理的数据。

一. GET请求

　　参数是通过Url来传输，接在Url后面中间用?分开，不同参数之间用&分开，也可不带参数，直接从服务器拉取数据。

GET 请求可被缓存
GET 请求保留在浏览器历史记录中
GET 请求可被收藏为书签
GET 请求不应在处理敏感数据时使用
GET 请求有长度限制
GET 请求只应当用于取回数据

 1             string result = String.Empty;
 2             string url = $"http://localhost:52307/API/CommonAPI/GetTest1?param1={100}&param2={200}";
 3             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
 4             request.Method = "GET";
 5             HttpWebResponse response = (HttpWebResponse)request.GetResponse();
 6             Stream stream = response.GetResponseStream();
 7             if (stream != null)
 8             {
 9                 using (StreamReader reader = new StreamReader(stream, Encoding.Default))
10                 {
11                     result = reader.ReadToEnd();
12                     reader.Close();
13                 }
14             }
15 
16             Console.WriteLine($"result={result}");
17             Console.ReadKey();

View Code

二. POST请求

　　请注意，查询字符串（名称/值对）是在 POST 请求的 HTTP 消息主体中发送的。

POST 请求不会被缓存
POST 请求不会保留在浏览器历史记录中
POST 不能被收藏为书签
POST 请求对数据长度没有要求

　　1. ContentType = "application/x-www-form-urlencoded"

 1             string result = String.Empty;
 2 
 3             string data = $"param1={100}&param2={200}";
 4             byte[] bytes = Encoding.Default.GetBytes(data);
 5 
 6             string url = $"http://localhost:52307/API/CommonAPI/PostTest2";
 7             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
 8             request.Method = "POST";
 9             request.ContentType = "application/x-www-form-urlencoded";
10             request.ContentLength = bytes.Length;
11             Stream requestStream = request.GetRequestStream();
12             requestStream.Write(bytes, 0, bytes.Length);
13             HttpWebResponse response = (HttpWebResponse)request.GetResponse();
14             Stream responseStream = response.GetResponseStream();
15             if (responseStream != null)
16             {
17                 using (StreamReader reader = new StreamReader(responseStream, Encoding.Default))
18                 {
19                     result = reader.ReadToEnd();
20                     reader.Close();
21                 }
22             }
23 
24             Console.WriteLine($"result={result}");
25             Console.ReadKey();

View Code

　　WebApi 获取请求参数：

　方法1.　

 1             try
 2             {
 3                 HttpContextBase httpContextBase = (HttpContextBase)Request.Properties["MS_HttpContext"];
 4                 HttpRequestBase httpRequestBase = httpContextBase.Request;
 5 
 6                 string param1 = httpRequestBase.Form["param1"];
 7                 string param2 = httpRequestBase.Form["param2"];
 8                 PrintLog.WriteLog(LogType.DEBUG, "CommonAPIController", "PostTest2", $"param1={param1},param2={param2}");
 9 
10                 return JsonConvert.SerializeObject(new { param1, param2 });
11             }
12             catch (Exception)
13             {
14 
15                 throw;
16             }

View Code

　方法2.　

 1         public string PostTest1([FromBody]AClass p)
 2         {
 3             try
 4             {
 5                 PrintLog.WriteLog(LogType.DEBUG, "CommonAPIController", "PostTest1", $"param1={p.Param1},param2={p.Param2}");
 6 
 7                 return JsonConvert.SerializeObject(new { p.Param1, p.Param2 });
 8             }
 9             catch (Exception)
10             {
11 
12                 throw;
13             }
14         }
15         public class AClass
16         {
17             public string Param1 { get; set; }
18             public string Param2 { get; set; }
19         }

View Code

　　2. ContentType = "application/json"

 1             string result = String.Empty;
 2 
 3             string data = "{"param1":100,"param2":200}";
 4             byte[] bytes = Encoding.Default.GetBytes(data);
 5 
 6             string url = $"http://localhost:52307/API/CommonAPI/PostTest1";
 7             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
 8             request.Method = "POST";
 9             request.ContentType = "application/json";
10             request.ContentLength = bytes.Length;
11             Stream requestStream = request.GetRequestStream();
12             requestStream.Write(bytes, 0, bytes.Length);
13             HttpWebResponse response = (HttpWebResponse)request.GetResponse();
14             Stream responseStream = response.GetResponseStream();
15             if (responseStream != null)
16             {
17                 using (StreamReader reader = new StreamReader(responseStream, Encoding.Default))
18                 {
19                     result = reader.ReadToEnd();
20                     reader.Close();
21                 }
22             }
23 
24             Console.WriteLine($"result={result}");
25             Console.ReadKey();

View Code

　　WebApi 获取请求参数：　

　　　　参见上面方法2.

　　3.multipart/form-data

　　它会将表单的数据处理为一条消息，以标签为单元，用分隔符（这就是boundary的作用）分

　　开。由于这种方式将数据有很多部分，它既可以上传键值对，也可以上传文件，甚至多个文

　　件。当上传的字段是文件时，会有Content-Type来说明文件类型；Content-disposition，用来

　　说明字段的一些信息。每部分都是以 – – –boundary 开始，紧接着是内容描述信息，然后是回

　　 车，最后是字段具体内容（字段、文本或二进制等）。如果传输的是文件，还要包含文件名和

　　 文件类型信息。消息主体最后以 – – –boundary– – – 标示结束。

　　　　如果只是传简单的字段没必要用此种类型。

　　　　请求侧：

 1             string result = String.Empty;
 2 
 3             string data = $"param1={300}&param2={600}";
 4             byte[] bytes = Encoding.Default.GetBytes(data);
 5             string url = "http://localhost:10486/API/TEST/PostMultipartFormData1";
 6             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
 7             request.Method = "POST";
 8             request.ContentType = "multipart/form-data";
 9             request.ContentLength = bytes.Length;
10             Stream requestStream = request.GetRequestStream();
11             requestStream.Write(bytes,0, bytes.Length);
12 
13             HttpWebResponse response = (HttpWebResponse)request.GetResponse();
14             Stream responseStream = response.GetResponseStream();
15             if (responseStream != null)
16             {
17                 using (StreamReader reader = new StreamReader(responseStream, Encoding.Default))
18                 {
19                     result = reader.ReadToEnd();
20                     reader.Close();
21                 }
22             }
23 
24             Console.WriteLine($"{result}");
25             Console.ReadKey();

View Code

　　　　接收侧：

 1         [HttpPost]
 2         public string PostMultipartFormData1()
 3         {
 4             string result = "";
 5             HttpContextBase context = (HttpContextBase)Request.Properties["MS_HttpContext"];
 6             HttpRequestBase request = context.Request;
 7 
 8             Stream stream = request.InputStream;
 9             using (StreamReader reader = new StreamReader(stream, Encoding.Default))
10             {
11                 result = reader.ReadToEnd();
12             }
13 
14             return result;
15         }

View Code

　　　　上传及保存文件1:（参考 https://blog.csdn.net/elie_yang/article/details/80710059 从HTTP的multipart/form-data分析看C#后台 HttpWebRequest文件上传

）：

　　　　请求侧：

 1             string result = "";
 2             string filePath = @"C:UsersPublicPicturesSample Pictures1.jpg";
 3             if (!File.Exists(filePath))
 4             {
 5                 return;
 6             }
 7             byte[] bytes = File.ReadAllBytes(filePath);
 8             string url = "http://localhost:10486/API/TEST/PostMultipartFormData2";
 9             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
10             // 边界符
11             var boundary = "---------------" + DateTime.Now.Ticks.ToString("x");
12             request.Method = "POST";
13             request.Timeout = 60000;
14             request.ContentType = "multipart/form-data; boundary=" + boundary;
15             // 开始边界符
16             var beginBoundary = Encoding.ASCII.GetBytes("--" + boundary + "
");
17             // 结束结束符
18             var endBoundary = Encoding.ASCII.GetBytes("--" + boundary + "--
");
19             // 换行
20             var newLineBytes = Encoding.UTF8.GetBytes("
");
21             using (var stream = new MemoryStream())
22             {
23                 // 1.写入开始边界符
24                 stream.Write(beginBoundary, 0, beginBoundary.Length);
25                 // 2.写入文件(name是参数名，filename是文件完整路径名)
26                 var fileHeader = "Content-Disposition: form-data; name={0}; filename={1}
" +
27                                  "Content-Type: application/octet-stream

";
28                 var fileHeaderBytes = Encoding.UTF8.GetBytes(string.Format(fileHeader, "file1", filePath));
29                 stream.Write(fileHeaderBytes, 0, fileHeaderBytes.Length);
30                 stream.Write(bytes, 0, bytes.Length);
31                 // 3.写入新行
32                 stream.Write(newLineBytes, 0, newLineBytes.Length);
33                 // 4.写入普通的文本值
34                 var keyValue = "Content-Disposition: form-data; name={0}

{1}
";
35                 var keyValueBytes = Encoding.UTF8.GetBytes(string.Format(keyValue, "param1", "ATest"));
36                 stream.Write(beginBoundary, 0, beginBoundary.Length);
37                 stream.Write(keyValueBytes, 0, keyValueBytes.Length);
38 
39                 // 5.写入结束边界符
40                 stream.Write(endBoundary, 0, endBoundary.Length);
41                 request.ContentLength = stream.Length;
42                 stream.Position = 0;
43                 var tempBuffer = new byte[stream.Length];
44                 stream.Read(tempBuffer, 0, tempBuffer.Length);
45                 //写入请求流
46                 using (Stream requestStream = request.GetRequestStream())
47                 {
48                     requestStream.Write(tempBuffer, 0, tempBuffer.Length);
49                     //获取响应
50                     using (var response = request.GetResponse())
51                     {
52                         using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
53                         {
54                             result = reader.ReadToEnd();
55                         }
56                     }
57                 }
58 
59             }
60 
61             Console.WriteLine($"{result}");
62             Console.ReadKey();

View Code

　　　　接收侧：

 1         [HttpPost]
 2         public string PostMultipartFormData2()
 3         {
 4             HttpContextBase context = (HttpContextBase)Request.Properties["MS_HttpContext"];
 5             HttpRequestBase request = context.Request;
 6 
 7             string param1 = request.Form["param1"];
 8             HttpPostedFileBase file = request.Files["file1"];
 9             int length = file.ContentLength;
10             string fileName = file.FileName;
11             string contentType = file.ContentType;
12             file.SaveAs(@"C:UsersPublicPicturesSample Pictures2.jpg");
13 
14             return $"length={length},fileName={fileName},contentType={contentType},param1={param1}";
15         }

View Code

　　　上传及保存文件2:

　　　请求侧：

 1             string result = "";
 2             string filePath = @"C:UsersPublicPicturesSample Pictures1.jpg";
 3             if (!File.Exists(filePath))
 4             {
 5                 return;
 6             }
 7             byte[] bytes = File.ReadAllBytes(filePath);
 8             string url = "http://localhost:10486/API/TEST/PostMultipartFormData3";
 9             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
10             request.Method = "POST";
11             request.Timeout = 60000;
12             request.ContentType = "multipart/form-data";
13             request.ContentLength = bytes.Length;
14             Stream requestStream = request.GetRequestStream();
15             requestStream.Write(bytes, 0, bytes.Length);
16             using (var response = request.GetResponse())
17             {
18                 using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
19                 {
20                     result = reader.ReadToEnd();
21                 }
22             }
23             Console.WriteLine($"{result}");

View Code　

　　　　接收侧：

 1         [HttpPost]
 2         public string PostMultipartFormData3()
 3         {
 4             HttpContextBase context = (HttpContextBase)Request.Properties["MS_HttpContext"];
 5             HttpRequestBase request = context.Request;
 6 
 7             Stream stream = request.InputStream;
 8             byte[] bytes = new byte[stream.Length];
 9             stream.Read(bytes, 0, bytes.Length);
10             stream.Seek(0, SeekOrigin.Begin);
11             FileStream fileStream = File.Create(@"C:UsersPublicPicturesSample Pictures3.jpg");
12             using (BinaryWriter writer = new BinaryWriter(fileStream, Encoding.Default))
13             {
14                 writer.Write(bytes);
15                 writer.Close();
16             }
17 
18             return $"success";
19         }

View Code

　　　　参考： https://blog.csdn.net/woaixiaoyu520/article/details/76690686 POST的Content-Type引发的HTTP相关知识思考

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原文地址：https://www.cnblogs.com/lu-yuan/p/12122234.html

C# HTTP请求 GET&POST

什么是 HTTP ？

GET - 从指定的资源请求数据。

POST - 向指定的资源提交要被处理的数据。

GET 请求可被缓存

GET 请求保留在浏览器历史记录中

GET 请求可被收藏为书签

GET 请求不应在处理敏感数据时使用

GET 请求有长度限制

GET 请求只应当用于取回数据

POST 请求不会被缓存

POST 请求不会保留在浏览器历史记录中

POST 不能被收藏为书签

POST 请求对数据长度没有要求