C#:如何使用套接字执行HTTP请求？

Question

我正在尝试HTTP request使用套接字.我的代码如下:

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class test
{
    public static void Main(String[] args)
    {
        string hostName = "127.0.0.1";
        int hostPort = 9887;
        int response = 0;

        IPAddress host = IPAddress.Parse(hostName);
        IPEndPoint hostep = new IPEndPoint(host, hostPort);
        Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

        sock.Connect(hostep);

        string request_url = "http://127.0.0.1/register?id=application/vnd-fullphat.test&title=My%20Test%20App";
        response = sock.Send(Encoding.UTF8.GetBytes(request_url));
        response = sock.Send(Encoding.UTF8.GetBytes("\r\n"));

        bytes = sock.Receive(bytesReceived, bytesReceived.Length, 0);
        page = page + Encoding.ASCII.GetString(bytesReceived, 0, bytes);
        Console.WriteLine(page);
        sock.Close();
    }
}

现在,当我执行上面的代码时没有任何反应,而当我进入我request_url的浏览器时,我收到来自Snarl的通知,说Application Registered我从浏览器获得的响应是

SNP/2.0/0/OK/556

我从我的代码得到的回应是SNP/3.0/107/BadPacket.

那么,我的代码出了什么问题.

Snarl请求格式规范

Answer 1

我对SNP一无所知.您的代码在接收部分有点混乱.我使用示例bellow来发送和读取HTTP GET请求的服务器响应.首先让我们看看请求,然后检查响应.

HTTP GET请求:

GET / HTTP/1.1
Host: 127.0.0.1
Connection: keep-alive
Accept: text/html
User-Agent: CSharpTests

string - "GET / HTTP/1.1\r\nHost: 127.0.0.1\r\nConnection: keep-alive\r\nAccept: text/html\r\nUser-Agent: CSharpTests\r\n\r\n"

服务器HTTP响应头:

HTTP/1.1 200 OK
Date: Sun, 07 Jul 2013 17:13:10 GMT
Server: Apache/2.4.4 (Win32) OpenSSL/0.9.8y PHP/5.4.16
Last-Modified: Sat, 30 Mar 2013 11:28:59 GMT
ETag: \"ca-4d922b19fd4c0\"
Accept-Ranges: bytes
Content-Length: 202
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html

string - "HTTP/1.1 200 OK\r\nDate: Sun, 07 Jul 2013 17:13:10 GMT\r\nServer: Apache/2.4.4 (Win32) OpenSSL/0.9.8y PHP/5.4.16\r\nLast-Modified: Sat, 30 Mar 2013 11:28:59 GMT\r\nETag: \"ca-4d922b19fd4c0\"\r\nAccept-Ranges: bytes\r\nContent-Length: 202\r\nKeep-Alive: timeout=5, max=100\r\nConnection: Keep-Alive\r\nContent-Type: text/html\r\n\r\n"

我故意省略了服务器响应的主体,因为我们已经知道它正好是202字节,由响应头中的Content-Length指定.

查看HTTP规范将显示HTTP标头以空的新行("\ r \n \n\r \n")结尾.所以我们只需要搜索它.

让我们看看一些代码在行动.假设System.Net.Sockets.Socket类型的变量套接字.

socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.Connect("127.0.0.1", 80);
string GETrequest = "GET / HTTP/1.1\r\nHost: 127.0.0.1\r\nConnection: keep-alive\r\nAccept: text/html\r\nUser-Agent: CSharpTests\r\n\r\n";
socket.Send(Encoding.ASCII.GetBytes(GETrequest));

我们已将请求发送到服务器,让我们接收并正确解析响应.

bool flag = true; // just so we know we are still reading
string headerString = ""; // to store header information
int contentLength = 0; // the body length
byte[] bodyBuff = new byte[0]; // to later hold the body content
while (flag)
{
// read the header byte by byte, until \r\n\r\n
byte[] buffer = new byte[1];
socket.Receive(buffer, 0, 1, 0);
headerString += Encoding.ASCII.GetString(buffer);
if (headerString.Contains("\r\n\r\n"))
{
    // header is received, parsing content length
    // I use regular expressions, but any other method you can think of is ok
    Regex reg = new Regex("\\\r\nContent-Length: (.*?)\\\r\n");
    Match m = reg.Match(headerString);
    contentLength = int.Parse(m.Groups[1].ToString());
    flag = false;
    // read the body
    bodyBuff = new byte[contentLength];
    socket.Receive(bodyBuff, 0, contentLength, 0);
}
}
Console.WriteLine("Server Response :");
string body = Encoding.ASCII.GetString(bodyBuff);
Console.WriteLine(body);
socket.Close();

这可能是在C#中执行此操作的最糟糕的方法,在.NET中有大量的类来处理HTTP请求和响应,但是如果您需要它,它仍然有效.

Answer 2

您必须在最后包含content-length和double new line以指示标题的结尾.

var request = "GET /register?id=application/vnd-fullphat.test&title=My%20Test%20App HTTP/1.1\r\n" + 
    "Host: 127.0.0.1\r\n" +
    "Content-Length: 0\r\n" +
    "\r\n";

HTTP 1.1规范可以在这里找到:http://www.w3.org/Protocols/rfc2616/rfc2616.html