如何在C++中使用Boost创建代理服务器

Question

我正在制作一个Web应用程序模糊器和我的代理服务器，我使用的是由Alex Ott开发的开源代码（现在）。我注意到，尽管当我从某些网站发出请求时，那些不会被捕获，所以我真的想用C++编写自己的代理，但我绝对不知道从哪里开始。有人可以向我解释吗？

最终目标是真正能够捕获和写入通过代理到达文件的每个请求，我已经在做，但现在我的代理服务器没有捕获所有这些请求，知道在那里。

编辑：由于问题不清楚，这里是：我想知道代码是用C++编写的使用Boost扩展库的代理服务器是什么。过去四个月同样的问题。

Answer 1

那么，这里有一个有点功能的例子，让你开始。它在两个连接之间转发。请注意，这个简单的示例不适用于Web浏览器，因为客户端将尝试建立多个连接，而此示例仅侦听一个连接。使用这个（非常简单）的基础，你应该能够取得一些进展。

有趣的东西发生在handle_read，这是接收数据时执行的回调。该函数在套接字之间转发数据。请注意，当我们最初称它为“本地”和“远程”连接时，我们通过套接字的顺序相反（read_from和write_to）。

#include <iostream> 
using namespace std; 

#include <boost/asio.hpp> 
#include <boost/lexical_cast.hpp> 
#include <boost/thread.hpp> 
#include <boost/bind.hpp> 

boost::asio::io_service& io_service() 
{ 
    static boost::asio::io_service svc; 
    return svc; 
} 

char local_data[1024] = {0}; 
char remote_data[1024] = {0}; 

void handle_read(
    boost::asio::ip::tcp::socket& read_from, 
    boost::asio::ip::tcp::socket& write_to, 
    char* read_buffer, 
    size_t bytes, 
    const boost::system::error_code& e) 
{ 
    // this function is called whenever data is received 

    // for debugging purposes, show the data in the console window 
    // or write to file, or whatever... 
    std::string data(read_buffer, read_buffer + bytes);  
    std::cout << data << "\n"; 

    // forward the received data on to "the other side"  
    write_to.send(
     boost::asio::buffer(read_buffer, bytes)); 

    // read more data from "this side" 
    read_from.async_read_some(
     boost::asio::buffer(read_buffer, 1024), 
     boost::bind(handle_read, boost::ref(read_from), boost::ref(write_to), read_buffer, boost::asio::placeholders::bytes_transferred, boost::asio::placeholders::error)); 
} 

int main(int argc, char** argv) 
{ 
    if(argc == 5) 
    { 
     boost::asio::io_service::work w(io_service()); 

     boost::thread t(boost::bind(&boost::asio::io_service::run, (&io_service()))); 

     // extract the connection information from the command line 
     boost::asio::ip::address local_address = boost::asio::ip::address::from_string(argv[1]); 
     uint16_t local_port = boost::lexical_cast<uint16_t>(argv[2]); 
     boost::asio::ip::address remote_address = boost::asio::ip::address::from_string(argv[3]); 
     uint16_t remote_port = boost::lexical_cast<uint16_t>(argv[4]); 

     boost::asio::ip::tcp::endpoint local_ep(local_address, local_port); 
     boost::asio::ip::tcp::endpoint remote_ep(remote_address, remote_port); 

     // start listening on the "local" socket -- note this does not 
     // have to be local, you could in theory forward through a remote device 
     // it's called "local" in the logical sense  
     boost::asio::ip::tcp::acceptor listen(io_service(), local_ep); 
     boost::asio::ip::tcp::socket local_socket(io_service()); 
     listen.accept(local_socket); 

     // open the remote connection 
     boost::asio::ip::tcp::socket remote_socket(io_service()); 
     remote_socket.open(remote_ep.protocol()); 
     remote_socket.connect(remote_ep); 

     // start listening for data on the "local" connection 
     local_socket.async_receive(
     boost::asio::buffer(local_data, 1024), 
     boost::bind(handle_read, boost::ref(local_socket), boost::ref(remote_socket), local_data, boost::asio::placeholders::bytes_transferred, boost::asio::placeholders::error)); 

     // also listen for data on the "remote" connection 
     remote_socket.async_receive(
     boost::asio::buffer(remote_data, 1024), 
     boost::bind(handle_read, boost::ref(remote_socket), boost::ref(local_socket), remote_data, boost::asio::placeholders::bytes_transferred, boost::asio::placeholders::error)); 

     t.join(); 
    } 
    else 
    { 
     cout << "proxy <local ip> <port> <remote ip> <port>\n"; 
    } 

    return 0; 
}