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C# 多线程 09-使用异步 I/O 02-编写一个异步的 HTTP 服务器和客户端 ​

🏷️ 《C# 多线程》

示例代码 ​

csharp
/// <summary>
/// 编写一个异步的 HTTP 服务器和客户端
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
    var server = new AsyncHttpServer(1234);
    var t = Task.Run(() => server.Start());
    Console.WriteLine("Listening on port 1234. Opent http://localhost:1234 iin your browser.");
    Console.WriteLine("Trying to conect:");
    Console.WriteLine();

    GetResponseAsync("http://localhost:1234").GetAwaiter().GetResult();

    Console.WriteLine();
    Console.WriteLine("Press Enter to stop the server");
    Console.ReadLine();

    server.Stop().GetAwaiter().GetResult();

    Console.WriteLine("Press Enter to exit");
    Console.ReadLine();
}

static async Task GetResponseAsync(string url)
{
    using (var client = new HttpClient())
    {
        HttpResponseMessage responseMessage = await client.GetAsync(url);
        string responseHeaders = responseMessage.Headers.ToString();
        string response = await responseMessage.Content.ReadAsStringAsync();

        Console.WriteLine("Response headers:");
        Console.WriteLine(responseHeaders);
        Console.WriteLine("Response body:");
        Console.WriteLine(response);
    }
}

class AsyncHttpServer
{
    // 使用 HttpListener 实现一个简单的服务器
    readonly HttpListener _listener;
    const string RESPONSE_TEMPLATE = "<html><head><title>Test</title></head><body><h2>Testpage</h2><h4>Today is: {0}</h4></body></html>";

    public AsyncHttpServer(int portNumber)
    {
        _listener = new HttpListener();
        _listener.Prefixes.Add($"http://localhost:{portNumber}/");
    }
    
    public async Task Start()
    {
        // 启动服务器
        _listener.Start();
        while (true)
        {
            // 调用 GetContextAsync 会发生异步 I/O 操作
            var ctx = await _listener.GetContextAsync();
            // 接收到请求时继续下面的处理
            Console.WriteLine("Client connected...");
            // 返回一个简单的 HTML 页面
            var response = string.Format(RESPONSE_TEMPLATE, DateTime.Now);

            using (var sw = new StreamWriter(ctx.Response.OutputStream))
            {
                await sw.WriteAsync(response);
                await sw.FlushAsync();
            }
        }
    }

    public async Task Stop()
    {
        // 调用 Abort 方法丢弃所有连接并关闭服务器
        _listener.Abort();
    }
}

运行结果 ​

txt
Listening on port 1234. Opent http://localhost:1234 iin your browser.
Trying to conect:

Client connected...
Response headers:
Transfer-Encoding: chunked
Date: Mon, 28 Aug 2017 08:38:11 GMT
Server: Microsoft-HTTPAPI/2.0

Response body:
<html><head><title>Test</title></head><body><h2>Testpage</h2><h4>Today is: 2017/
8/28 16:38:11</h4></body></html>

Press Enter to stop the server
Client connected...
Client connected...

Press Enter to exit