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[ASP.net教程]通过HttpListener实现简单的Http服务


使用HttpListener实现简单的Http服务

HttpListener提供一个简单的、可通过编程方式控制的 HTTP 协议侦听器.使用它可以很容易的提供一些Http服务,而无需启动IIS这类大型服务程序。使用HttpListener的方法流程很简单:主要分为以下几步
  1. 创建一个HTTP侦听器对象并初始化
  2. 添加需要监听的URI 前缀
  3. 开始侦听来自客户端的请求
  4. 处理客户端的Http请求
  5. 关闭HTTP侦听器

例如:我们要实现一个简单Http服务,进行文件的下载,或者进行一些其他的操作,例如要发送邮件,使用HttpListener监听,处理邮件队列,避免在网站上的同步等待。以及获取一些缓存的数据等等行为

using System;using System.Collections.Generic;using System.Linq;using System.Net;using System.Text;using System.Threading;using System.Web;using System.IO;using Newtonsoft.Json;namespace HttpListenerApp{  /// <summary>  /// HttpRequest逻辑处理  /// </summary>  public class HttpProvider  {    private static HttpListener httpFiledownload; //文件下载处理请求监听    private static HttpListener httOtherRequest;  //其他超做请求监听    /// <summary>    /// 开启HttpListener监听    /// </summary>    public static void Init()    {      httpFiledownload = new HttpListener(); //创建监听实例      httpFiledownload.Prefixes.Add("http://10.0.0.217:20009/FileManageApi/Download/"); //添加监听地址 注意是以/结尾。      httpFiledownload.Start(); //允许该监听地址接受请求的传入。      Thread ThreadhttpFiledownload = new Thread(new ThreadStart(GethttpFiledownload)); //创建开启一个线程监听该地址得请求      ThreadhttpFiledownload.Start();      httOtherRequest = new HttpListener();      httOtherRequest.Prefixes.Add("http://10.0.0.217:20009/BehaviorApi/EmailSend/"); //添加监听地址 注意是以/结尾。      httOtherRequest.Start(); //允许该监听地址接受请求的传入。      Thread ThreadhttOtherRequest = new Thread(new ThreadStart(GethttOtherRequest));      ThreadhttOtherRequest.Start();    }    /// <summary>    /// 执行文件下载处理请求监听行为    /// </summary>    public static void GethttpFiledownload()    {      while (true)      {        HttpListenerContext requestContext = httpFiledownload.GetContext(); //接受到新的请求        try        {          //reecontext 为开启线程传入的 requestContext请求对象          Thread subthread = new Thread(new ParameterizedThreadStart((reecontext) =>             {            Console.WriteLine("执行文件处理请求监听行为");            var request = (HttpListenerContext)reecontext;            var image = HttpUtility.UrlDecode(request.Request.QueryString["imgname"]); //接受GET请求过来的参数;            string filepath = AppDomain.CurrentDomain.BaseDirectory + image;            if (!File.Exists(filepath))            {              filepath = AppDomain.CurrentDomain.BaseDirectory + "default.jpg";    //下载默认图片            }            using (FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read))            {              byte[] buffer = new byte[fs.Length];              fs.Read(buffer, 0, (int)fs.Length); //将文件读到缓存区              request.Response.StatusCode = 200;              request.Response.Headers.Add("Access-Control-Allow-Origin", "*");              request.Response.ContentType = "image/jpg";               request.Response.ContentLength64 = buffer.Length;              var output = request.Response.OutputStream; //获取请求流              output.Write(buffer, 0, buffer.Length);   //将缓存区的字节数写入当前请求流返回              output.Close();            }          }));          subthread.Start(requestContext); //开启处理线程处理下载文件        }        catch (Exception ex)        {          try          {            requestContext.Response.StatusCode = 500;            requestContext.Response.ContentType = "application/text";            requestContext.Response.ContentEncoding = Encoding.UTF8;            byte[] buffer = System.Text.Encoding.UTF8.GetBytes("System Error");            //对客户端输出相应信息.            requestContext.Response.ContentLength64 = buffer.Length;            System.IO.Stream output = requestContext.Response.OutputStream;            output.Write(buffer, 0, buffer.Length);            //关闭输出流,释放相应资源            output.Close();          }          catch { }        }      }    }    /// <summary>    /// 执行其他超做请求监听行为    /// </summary>    public static void GethttOtherRequest()    {      while (true)      {        HttpListenerContext requestContext = httOtherRequest.GetContext(); //接受到新的请求        try        {          //reecontext 为开启线程传入的 requestContext请求对象          Thread subthread = new Thread(new ParameterizedThreadStart((reecontext) =>          {            Console.WriteLine("执行其他超做请求监听行为");            var request = (HttpListenerContext)reecontext;            var msg = HttpUtility.UrlDecode(request.Request.QueryString["behavior"]); //接受GET请求过来的参数;            //在此处执行你需要进行的操作>>比如什么缓存数据读取,队列消息处理,邮件消息队列添加等等。            request.Response.StatusCode = 200;            request.Response.Headers.Add("Access-Control-Allow-Origin", "*");            request.Response.ContentType = "application/json";            requestContext.Response.ContentEncoding = Encoding.UTF8;            byte[] buffer = System.Text.Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(new { success = true, behavior = msg }));            request.Response.ContentLength64 = buffer.Length;            var output = request.Response.OutputStream;            output.Write(buffer, 0, buffer.Length);            output.Close();          }));          subthread.Start(requestContext); //开启处理线程处理下载文件        }        catch (Exception ex)        {          try          {            requestContext.Response.StatusCode = 500;            requestContext.Response.ContentType = "application/text";            requestContext.Response.ContentEncoding = Encoding.UTF8;            byte[] buffer = System.Text.Encoding.UTF8.GetBytes("System Error");            //对客户端输出相应信息.            requestContext.Response.ContentLength64 = buffer.Length;            System.IO.Stream output = requestContext.Response.OutputStream;            output.Write(buffer, 0, buffer.Length);            //关闭输出流,释放相应资源            output.Close();          }          catch { }        }      }    }  }}

调用方式:注意这里启动程序必须以管理员身份运行,因为上午的监听需要开启端口,所有需要以管理员身份运行。

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace HttpListenerApp{  class Program  {    static void Main(string[] args)    {      //开启请求监听      HttpProvider.Init();    }  }}

执行后的结果为:


这里通过一个简单的控制程序在里面使用HttpListener实现了简单的Http服务程序。里面有少量的线程和和异步处理,比如收到行为信息请求可以先返回给用户,让用户不用同步等待,就可以执行下一步操作,又比如实现的简单邮件服务器,将请求发给HttpListener接收到请求后就立即返回,交给队列去发送邮件。邮件的发送会出现延迟等待等情况出现,这样就不用等待。等等