proxy-conn.cpp

/**
 * @file   proxy-conn.cpp
 * @author Alex Ott <alexott@gmail.com>
 * 
 * @brief  
 * 
 * 
 */

#include "proxy-conn.hpp"

/** 
 * 
 * 
 * @param io_service 
 */
connection::connection(ba::io_service& io_service) : io_service_(io_service),
													 bsocket_(io_service),
													 ssocket_(io_service),
													 resolver_(io_service),
													 proxy_closed(false),
													 isPersistent(false),
													 isOpened(false) 
{
	fHeaders.reserve(8192);
}

/** 
 * Start read data of request from browser
 * 
 */
void connection::start() {
//  	std::cout << "start" << std::endl;
	fHeaders.clear();
	reqHeaders.clear();
	respHeaders.clear();
	
	handle_browser_read_headers(bs::error_code(), 0);
}

/** 
 * Read header of HTTP request from browser
 * 
 * @param err 
 * @param len 
 */
void connection::handle_browser_read_headers(const bs::error_code& err, size_t len) {
//  	std::cout << "handle_browser_read_headers. Error: " << err << ", len=" << len << std::endl;
	if(!err) {
		if(fHeaders.empty())
			fHeaders=std::string(bbuffer.data(),len);
		else
			fHeaders+=std::string(bbuffer.data(),len);
		if(fHeaders.find("\r\n\r\n") == std::string::npos) { // going to read rest of headers
			async_read(bsocket_, ba::buffer(bbuffer), ba::transfer_at_least(1),
					   boost::bind(&connection::handle_browser_read_headers,
								   shared_from_this(),
								   ba::placeholders::error,
								   ba::placeholders::bytes_transferred));
		} else { // analyze headers
			//std::cout << "fHeaders:\n" << fHeaders << std::endl;
			std::string::size_type idx=fHeaders.find("\r\n");
			std::string reqString=fHeaders.substr(0,idx);
			fHeaders.erase(0,idx+2);

			idx=reqString.find(" ");
			if(idx == std::string::npos) {
				std::cout << "Bad first line: " << reqString << std::endl;
				return;
			}
			
			fMethod=reqString.substr(0,idx);
			reqString=reqString.substr(idx+1);
			idx=reqString.find(" ");
			if(idx == std::string::npos) {
				std::cout << "Bad first line of request: " << reqString << std::endl;
				return;
			}
			fURL=reqString.substr(0,idx);
			fReqVersion=reqString.substr(idx+1);
			idx=fReqVersion.find("/");
			if(idx == std::string::npos) {
				std::cout << "Bad first line of request: " << reqString << std::endl;
				return;
			}
			fReqVersion=fReqVersion.substr(idx+1);
			
			// string outputs to console completely, even when using multithreading
			//std::cout << std::string("\n fMethod: " + fMethod + ", fURL: " + fURL + ", fReqVersion: " + fReqVersion + "\n");
			// analyze headers, etc
			parseHeaders(fHeaders,reqHeaders);
			//
			start_connect();
		}
	} else {
		shutdown();
	}
}

/** 
 * Start connecting to the web-server, initially to resolve the DNS-name of web-server into the IP address
 * 
 */
void connection::start_connect() {
	std::string server="";
	std::string port="80";
	boost::regex rHTTP("http://(.*?)(:(\\d+))?(/.*)");
	boost::smatch m;
	
	if(boost::regex_search(fURL, m, rHTTP, boost::match_extra)) {
		server=m[1].str();
		if(m[2].str() != "") {
			port=m[3].str();
		}
		fNewURL=m[4].str();
	}
	if(server.empty()) {
		std::cout << "Can't parse URL "<< std::endl;
		return;
	}
//	std::cout << server << " " << port << " " << fNewURL << std::endl;
	
	if(!isOpened || server != fServer || port != fPort) {
		fServer=server;
		fPort=port;
		ba::ip::tcp::resolver::query query(server, port);
		resolver_.async_resolve(query,
								boost::bind(&connection::handle_resolve, shared_from_this(),
											boost::asio::placeholders::error,
											boost::asio::placeholders::iterator));
	} else {
	    start_write_to_server();
	}
}

/** 
 * If successful, after the resolved DNS-names of web-server into the IP addresses, try to connect
 * 
 * @param err 
 * @param endpoint_iterator 
 */
void connection::handle_resolve(const boost::system::error_code& err,
								ba::ip::tcp::resolver::iterator endpoint_iterator) {
//	std::cout << "handle_resolve. Error: " << err.message() << "\n";
    if (!err) {
		const bool first_time = true;
		handle_connect(boost::system::error_code(), endpoint_iterator, first_time);
    }else {
		shutdown();
	}
}

/** 
 * Try to connect to the web-server
 * 
 * @param err 
 * @param endpoint_iterator 
 */
void connection::handle_connect(const boost::system::error_code& err,
								ba::ip::tcp::resolver::iterator endpoint_iterator, const bool first_time) {
//	std::cout << "handle_connect. Error: " << err << "\n";
    if (!err && !first_time) {
		isOpened=true;
		start_write_to_server();
    } else if (endpoint_iterator != ba::ip::tcp::resolver::iterator()) {
		//ssocket_.close();
		ba::ip::tcp::endpoint endpoint = *endpoint_iterator;
		ssocket_.async_connect(endpoint,
							   boost::bind(&connection::handle_connect, shared_from_this(),
										   boost::asio::placeholders::error,
										   ++endpoint_iterator, false));
    } else {
		shutdown();
	}
}

/** 
 * Write data to the web-server
 * 
 */
void connection::start_write_to_server() {
	fReq=fMethod;
	fReq+=" ";
	fReq+=fNewURL;
	fReq+=" HTTP/";
	fReq+="1.0";
//	fReq+=fReqVersion;
	fReq+="\r\n";
	fReq+=fHeaders;
//	std::cout << "Request: " << Req << std::endl;
	ba::async_write(ssocket_, ba::buffer(fReq),
					boost::bind(&connection::handle_server_write, shared_from_this(),
								ba::placeholders::error,
								ba::placeholders::bytes_transferred));

	fHeaders.clear();
}

/** 
 * If successful, read the header that came from a web server
 * 
 * @param err 
 * @param len 
 */
void connection::handle_server_write(const bs::error_code& err, size_t len) {
// 	std::cout << "handle_server_write. Error: " << err << ", len=" << len << std::endl;
	if(!err) {
		handle_server_read_headers(bs::error_code(), 0);
	}else {
		shutdown();
	}
}

/** 
 * Read header of data returned from the web-server
 * 
 * @param err 
 * @param len 
 */
void connection::handle_server_read_headers(const bs::error_code& err, size_t len) {
// 	std::cout << "handle_server_read_headers. Error: " << err << ", len=" << len << std::endl;
	if(!err) {
		std::string::size_type idx;
		if(fHeaders.empty())
			fHeaders=std::string(sbuffer.data(),len);
		else
			fHeaders+=std::string(sbuffer.data(),len);
		idx=fHeaders.find("\r\n\r\n");
		if(idx == std::string::npos) { // going to read rest of headers
			async_read(ssocket_, ba::buffer(sbuffer), ba::transfer_at_least(1),
					   boost::bind(&connection::handle_server_read_headers,
								   shared_from_this(),
								   ba::placeholders::error,
								   ba::placeholders::bytes_transferred));
		} else { // analyze headers
//			std::cout << "Response: " << fHeaders << std::endl;
			RespReaded=len-idx-4;
			idx=fHeaders.find("\r\n");
 			std::string respString=fHeaders.substr(0,idx);
			RespLen = -1;
			parseHeaders(fHeaders.substr(idx+2),respHeaders);
			std::string reqConnString="",respConnString="";

			std::string respVersion=respString.substr(respString.find("HTTP/")+5,3);
			
			headersMap::iterator it=respHeaders.find("Content-Length");
			if(it != respHeaders.end())
				RespLen=boost::lexical_cast<int>(it->second);
			it=respHeaders.find("Connection");
			if(it != respHeaders.end())
				respConnString=it->second;
			it=reqHeaders.find("Connection");
			if(it != reqHeaders.end())
				reqConnString=it->second;
			
			isPersistent=(
				((fReqVersion == "1.1" && reqConnString != "close") ||
				 (fReqVersion == "1.0" && reqConnString == "keep-alive")) &&
				((respVersion == "1.1" && respConnString != "close") ||
				 (respVersion == "1.0" && respConnString == "keep-alive")) &&
				RespLen != -1);
// 			std::cout << "RespLen: " << RespLen << " RespReaded: " << RespReaded
// 					  << " isPersist: " << isPersistent << std::endl;
			
			// sent data
			ba::async_write(bsocket_, ba::buffer(fHeaders),
							boost::bind(&connection::handle_browser_write,
										shared_from_this(),
										ba::placeholders::error,
										ba::placeholders::bytes_transferred));
		}
	} else {
		shutdown();
	}
}

/** 
 * Writing data to the browser, are recieved from web-server
 * 
 * @param err 
 * @param len 
 */
void connection::handle_browser_write(const bs::error_code& err, size_t len) {
//   	std::cout << "handle_browser_write. Error: " << err << " " << err.message()
//  			  << ", len=" << len << std::endl;
	if(!err) {
		if(!proxy_closed && (RespLen == -1 || RespReaded < RespLen))
			async_read(ssocket_, ba::buffer(sbuffer,len), ba::transfer_at_least(1),
					   boost::bind(&connection::handle_server_read_body,
								   shared_from_this(),
								   ba::placeholders::error,
								   ba::placeholders::bytes_transferred));
		else {
//			shutdown();
 			if(isPersistent && !proxy_closed) {
  				std::cout << "Starting read headers from browser, as connection is persistent" << std::endl;
  				start();
 			}
		}
	} else {
		shutdown();
	}
}

/** 
 * Reading data from a Web server, for the writing them to the browser
 * 
 * @param err 
 * @param len 
 */
void connection::handle_server_read_body(const bs::error_code& err, size_t len) {
//   	std::cout << "handle_server_read_body. Error: " << err << " " << err.message()
//  			  << ", len=" << len << std::endl;
	if(!err || err == ba::error::eof) {
		RespReaded+=len;
// 		std::cout << "len=" << len << " resp_readed=" << RespReaded << " RespLen=" << RespLen<< std::endl;
		if(err == ba::error::eof)
			proxy_closed=true;
		ba::async_write(bsocket_, ba::buffer(sbuffer,len),
						boost::bind(&connection::handle_browser_write,
									shared_from_this(),
									ba::placeholders::error,
									ba::placeholders::bytes_transferred));
	} else {
		shutdown();
	}
}

/** 
 * Close both sockets: for browser and web-server
 * 
 */
void connection::shutdown() {
	if (ssocket_.is_open())
	{
		ssocket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
		ssocket_.close();
	}
	if (bsocket_.is_open())
	{
		bsocket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
		bsocket_.close();
	}
}


void connection::parseHeaders(const std::string& h, headersMap& hm) {
	std::string str(h);
	std::string::size_type idx;
	std::string t;
	while((idx=str.find("\r\n")) != std::string::npos) {
		t=str.substr(0,idx);
		str.erase(0,idx+2);
		if(t == "")
			break;
		idx=t.find(": ");
		if(idx == std::string::npos) {
			std::cout << "Bad header line: " << t << std::endl;
			break;
		}
// 		std::cout << "Name: " << t.substr(0,idx) 
// 				  << " Value: " << t.substr(idx+2) << std::endl;
		hm.insert(std::make_pair(t.substr(0,idx),t.substr(idx+2)));
	}
}