HTTP 1.1请求消息不能获得最后一个字节块，而通过套接字获取结果 [英] HTTP 1.1 request message cannot get last chunk of bytes, while getting result through socket

问题描述

这是我的Scratch代码：

Here is my scratch code:

using System;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace SocketsDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            Uri uri;
            if (args.Any()) uri = new Uri(args[0]);
            else uri = new Uri("http://odetocode.com/Articles/473.aspx"); //http://www.odetocode.com
            var result = GetResource(uri);
            Console.WriteLine(result);
            Console.ReadLine();
        }

        private static string GetResource(Uri uri)
        {
            var host = uri.Host;
            var resource = uri.PathAndQuery;
            var hostEntry = Dns.GetHostEntry(host);

            var socket = CreateSocket(hostEntry);
            SendRequest(socket, host, resource);
            return GetResponse(socket);
        }

        private static Socket CreateSocket(IPHostEntry hostEntry)
        {
            const int HTTP_PORT = 80;
            var endPoint = new IPEndPoint(hostEntry.AddressList[0], HTTP_PORT);
            var socket = new Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
            socket.Connect(endPoint);
            return socket.Connected ? socket : null;
        }

        private static void SendRequest(Socket socket, string host, string resource)
        {
            var requestMessage = String.Format(
                "GET {0} HTTP/1.1\r\n" +
                "HOST: {1}\r\n" +
                "\r\n", resource, host);

            var requestBytes = Encoding.ASCII.GetBytes(requestMessage);
            socket.Send(requestBytes);
        }

        private static string GetResponse(Socket socket)
        {
            int bytesCount = 0;
            var buffer = new byte[256];
            var result = new StringBuilder();

            do
            {
                bytesCount = socket.Receive(buffer);
                result.Append(Encoding.ASCII.GetString(buffer, 0, bytesCount));
            } while (bytesCount > 0);
            return result.ToString();
        }
    }
}

请求消息在 SendRequest 方法到HTTP / 1.0 - 一切工作。
但是当我尝试在HTTP / 1.1上重复这个，这个块 do {..} while（bytesCount> 0）挂起181周期。看起来像服务器或客户端不能处理最后一块字节。

When i change HTTP part of request message in SendRequest method to HTTP/1.0 - everything working. But when I try to repeat this on HTTP/1.1, this block do { .. } while (bytesCount > 0) hangs out on 181 cycle. Looks like server or client cannot deal with last chunk of bytes. Can anybody explain what stays behind this and how i can repair this with smallest changes to existing code.

推荐答案

这是一个很好的解决方案。 http的保持活动的特征。服务器在发送其消息后不会断开连接，让您等待进一步的数据。

That's the keep-alive "feature" of http. The server does not disconnect after sending its message, keeping you waiting for further data.

您必须解析HTTP头。如果有一个 Transfer-Encoding：chunked ，你必须解析你接收的块，直到你收到一个0字节的块。

You'll have to parse the HTTP headers. If there's a Transfer-Encoding: chunked, you'll have to parse the chunks you're receiving until you receive a chunk of 0 bytes.

如果不是以块的形式发送，你必须解析一个 Content-Length 头来查看总共读取多少字节。

If it isn't sent as chunks, you'll have to parse a Content-Length header to see how many bytes total to read.

HTTP / 1.0不支持块，并且某些客户端不支持保持连接活动，因此对于HTTP / 1.0，保持活动 off ，而对于HTTP / 1.1，默认为 on 。

HTTP/1.0 did not support chunks and some clients did not support keeping the connection alive, so for HTTP/1.0 the default server behavior should be keep-alive off, while for HTTP/1.1 the default is on.

请参阅 http://en.wikipedia.org/wiki/Chunked_transfer_encoding

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