利用HttpListener创建简单的HTTP服务

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
public class HttpServer : IDisposable
{
    private const string NotFoundResponse = "<!doctype html><html><body>Resource not found</body></html>";
    private readonly HttpListener httpListener;
    private readonly CancellationTokenSource cts = new CancellationTokenSource();
    private readonly string prefixPath;

    private Task processingTask;

    public HttpServer(string listenerUriPrefix)
    {
        this.prefixPath = ParsePrefixPath(listenerUriPrefix);
        this.httpListener = new HttpListener();
        this.httpListener.Prefixes.Add(listenerUriPrefix);
    }

    private static string ParsePrefixPath(string listenerUriPrefix)
    {
        var match = Regex.Match(listenerUriPrefix, @"http://(?:[^/]*)(?:\:\d+)?/(.*)");
        if (match.Success)
        {
            return match.Groups[1].Value.ToLowerInvariant();
        }
        else
        {
            return string.Empty;
        }
    }

    public void Start()
    {
        this.httpListener.Start();
        this.processingTask = Task.Factory.StartNew(async () => await ProcessRequests(), TaskCreationOptions.LongRunning);
    }

    private async Task ProcessRequests()
    {
        while (!this.cts.IsCancellationRequested)
        {
            try
            {
                var context = await this.httpListener.GetContextAsync();
                try
                {
                    await ProcessRequest(context).ConfigureAwait(false);
                    context.Response.Close();
                }
                catch (Exception ex)
                {
                    context.Response.StatusCode = 500;
                    context.Response.StatusDescription = "Internal Server Error";
                    context.Response.Close();
                    Console.WriteLine("Error processing HTTP request\n{0}", ex);
                }
            }
            catch (ObjectDisposedException ex)
            {
                if ((ex.ObjectName == this.httpListener.GetType().FullName) && (this.httpListener.IsListening == false))
                {
                    return; // listener is closed/disposed
                }
                Console.WriteLine("Error processing HTTP request\n{0}", ex);
            }
            catch (Exception ex)
            {
                HttpListenerException httpException = ex as HttpListenerException;
                if (httpException == null || httpException.ErrorCode != 995)// IO operation aborted
                {
                    Console.WriteLine("Error processing HTTP request\n{0}", ex);
                }
            }
        }
    }

    private Task ProcessRequest(HttpListenerContext context)
    {
        if (context.Request.HttpMethod.ToUpperInvariant() != "GET")
        {
            return WriteNotFound(context);
        }

        var urlPath = context.Request.RawUrl.Substring(this.prefixPath.Length)
            .ToLowerInvariant();

        switch (urlPath)
        {
            case "/":
                if (!context.Request.Url.ToString().EndsWith("/"))
                {
                    context.Response.Redirect(context.Request.Url + "/");
                    context.Response.Close();
                    return Task.FromResult(0);
                }
                else
                {
                    return WriteString(context, "Hello World!", "text/plain");
                }
            case "/favicon.ico":
                return WriteFavIcon(context);
            case "/ping":
                return WritePong(context);
        }
        return WriteNotFound(context);
    }

    private static Task WritePong(HttpListenerContext context)
    {
        return WriteString(context, "pong", "text/plain");
    }

    private static async Task WriteFavIcon(HttpListenerContext context)
    {
        context.Response.ContentType = "image/png";
        context.Response.StatusCode = 200;
        context.Response.StatusDescription = "OK";
        using (var stream = File.Open("icon.png", FileMode.Open))
        {
            var output = context.Response.OutputStream;
            await stream.CopyToAsync(output);
        }
    }

    private static Task WriteNotFound(HttpListenerContext context)
    {
        return WriteString(context, NotFoundResponse, "text/plain", 404, "NOT FOUND");
    }

    private static async Task WriteString(HttpListenerContext context, string data, string contentType,
        int httpStatus = 200, string httpStatusDescription = "OK")
    {
        AddCORSHeaders(context.Response);
        AddNoCacheHeaders(context.Response);

        context.Response.ContentType = contentType;
        context.Response.StatusCode = httpStatus;
        context.Response.StatusDescription = httpStatusDescription;

        var acceptsGzip = AcceptsGzip(context.Request);
        if (!acceptsGzip)
        {
            using (var writer = new StreamWriter(context.Response.OutputStream, Encoding.UTF8, 4096, true))
            {
                await writer.WriteAsync(data).ConfigureAwait(false);
            }
        }
        else
        {
            context.Response.AddHeader("Content-Encoding", "gzip");
            using (GZipStream gzip = new GZipStream(context.Response.OutputStream, CompressionMode.Compress, true))
            using (var writer = new StreamWriter(gzip, Encoding.UTF8, 4096, true))
            {
                await writer.WriteAsync(data).ConfigureAwait(false);
            }
        }
    }


    private static bool AcceptsGzip(HttpListenerRequest request)
    {
        string encoding = request.Headers["Accept-Encoding"];
        if (string.IsNullOrEmpty(encoding))
        {
            return false;
        }

        return encoding.Contains("gzip");
    }

    private static void AddNoCacheHeaders(HttpListenerResponse response)
    {
        response.Headers.Add("Cache-Control", "no-cache, no-store, must-revalidate");
        response.Headers.Add("Pragma", "no-cache");
        response.Headers.Add("Expires", "0");
    }

    private static void AddCORSHeaders(HttpListenerResponse response)
    {
        response.Headers.Add("Access-Control-Allow-Origin", "*");
        response.Headers.Add("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
    }

    private void Stop()
    {
        cts.Cancel();
        if (processingTask != null && !processingTask.IsCompleted)
        {
            processingTask.Wait();
        }
        if (this.httpListener.IsListening)
        {
            this.httpListener.Stop();
            this.httpListener.Prefixes.Clear();
        }
    }

    public void Dispose()
    {
        this.Stop();
        this.httpListener.Close();
        using (this.cts) { }
        using (this.httpListener) { }
    }
}
posted @ 2016-04-07 18:36 binking338 阅读(3280) 评论(0) 编辑收藏举报
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利用HttpListener创建简单的HTTP服务

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