Example: Receive HTTP Post via ASP.Net Generic Handler 转

假设我们要提供一个小小的服务，采用HTTP协议进行通讯，客户端 POST 一些数据到服务器上。客户端不一定是PC，更不一定会按照一个Web Form的格式来提交数据，它可能是一个运行在PC上的Desktop Application，也可能是一个移动设备。

 

服务器端接收这样的请求极其简单，下面寥寥数行代码即可实现：

在Web站点中新建一个Generic Handler（*.ashx），代码如下：

<%@ WebHandler Language=
"C#"
 Class=
"Echo"
 %>

using
 System;
using
 System.Web;
using
 System.IO;

public
 
class
 Echo : IHttpHandler
{
    private
 System.Text.Encoding DefaultEncoding = System.Text.Encoding.UTF8;

    public
 
void
 ProcessRequest (HttpContext context)
    {
        context.Response.ContentType = "text/plain"
;
        context.Response.ContentEncoding = DefaultEncoding;

        Stream inputStream = context.Request.InputStream;
        using
 (StreamReader reader = 
new
 StreamReader(inputStream, DefaultEncoding))
        {
            string
 requestContent = reader.ReadToEnd();
            string
 responseContent = 
string
.Format(
"Received: {0} <== END"
, requestContent);

            context.Response.Write(responseContent);
        }
    }

    public
 
bool
 IsReusable
    {
        get
 { 
return
 
false
; }
    }
}

然后我们写一个简单的客户端来测试它。在这个客户端里我们实现了一个类HttpClient来进行HTTP POST操作：

// -----------------------------------------------------------------------
// <copyright file="HttpClient.cs" author="Yaping Xin">
// Http protocol client.
// </copyright>
// -----------------------------------------------------------------------

namespace
 ConsoleClient
{
    using
 System;
    using
 System.IO;
    using
 System.Net;
    using
 System.Text;

    /// <summary>
    /// Http protocol client.
    /// </summary>
    public
 
class
 HttpClient
    {
        /// <summary>
        /// Post data to specific url and get response content.
        /// </summary>
        /// <param name="url">the url to post</param>
        /// <param name="postData">post data</param>
        /// <returns>response content</returns>
        public
 
string
 Post(
string
 url, 
string
 postData)
        {
            Uri uri = new
 Uri(url);
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
            request.Method = "POST"
;
            request.ContentType = "application/x-www-form-urlencoded"
;

            Encoding encoding = Encoding.UTF8;
            byte
[] bytes = encoding.GetBytes(postData);

            request.ContentLength = bytes.Length;

            using
 (Stream writer = request.GetRequestStream())
            {
                writer.Write(bytes, 0, bytes.Length);
                writer.Close();
            }

            return
 
this
.ReadResponse(request);;
        }

        /// <summary>
        /// Read response content from http request result.
        /// </summary>
        /// <param name="request">http request object</param>
        /// <returns>response content.</returns>
        private
 
string
 ReadResponse(HttpWebRequest request)
        {
            string
 result = 
string
.Empty;

            using
 (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                using
 (Stream responseStream = response.GetResponseStream())
                {
                    using
 (StreamReader reader = 
new
 StreamReader(responseStream, Encoding.UTF8))
                    {
                        result = reader.ReadToEnd();
                        reader.Close();
                    }
                }
            }

            return
 result;
        }
    }
}

然后我们这样就能得到HTTP POST的返回：

// Replace the string content with your actual address please.
string
 defaultUrl = 
"http://ServerName:8081/WebPath/AnyService.ashx"
;

HttpClient client = new
 HttpClient();
string
 response = client.Post(defaultUrl, @
"abc 123! 测试 @"
);

Console.OutputEncoding = System.Text.Encoding.UTF8;
Console.WriteLine(response);

假设Client与Server两端都约定好采取某个格式对数据进行序列化与反序列化，例如都采用Json，客户端把对象通过Json封装后 Post给Server，Server再采用Json将对象从Json字符串中解析出来，这样进行数据传递是便利的。再假设我们要压缩传送出的数据量，那 么可以进行gzip压缩与解压。又假设我们要考虑安全性，那么我们可以在对象的结构中添加security token进行认证，以及采用某种加密算法对字符串进行加密与解密。怎么发挥就看您具体的应用了，构建一个属于您自己的轻量的service易如反掌。