Re: [Boost-users] How to upload a file with ASIO

Subject: Re: [Boost-users] How to upload a file with ASIO
From: Ramon F Herrera (ramon_at_[hidden])
Date: 2009-11-03 11:36:50

Benjamin Sobotta wrote:

> Hello,
> 
> It would be interesting to know *how* you exactly transfer the 
> information at hand and then build a solution from there.
> 
> Anyways, I use ASIO in conjunction with boost::serialization. There is 
> an example on the ASIO website. I found that combination extremely 
> handy. With this approach one could easily transfer any kind of data, 
> for example in a std::vector.
> 
> hth,
> 
> Benjamin
> 
> 

Hi Benjamin,

Find below the relevant snippets of the client and the server code. As 
you can see, I keep on sending parameters, separated by newlines. Two 
consecutive newlines denote end of input. This obviously does not scale 
to a more complex transfer (i.e., a complete binary file).

Thanks for your kind assistance,

-Ramon

----------------------------------------
Client:

         // stream
         boost::asio::streambuf    buf;
         std::ostream              net_out(&buf);

         // Display the arguments

         if (debug()) cout << "client pushing " <<  argc - 1  << " 
arguments" << endl;

         for (int i = 1; i < argc; i++) {
             net_out << argv[i] << endl;
             if (debug()) cout << "arg[" << i << "], " << argv[i] << " 
was pushed" << endl;
         }

         net_out << endl;

         boost::asio::write(socket, buf);

         while (true) {

             boost::array<char, 128> buf;
             boost::system::error_code error;

             size_t len = socket.read_some(boost::asio::buffer(buf), error);

             if (error == boost::asio::error::eof)
                 break; // Connection closed cleanly by peer.

             else if (error)
                 throw boost::system::system_error(error); // Some other 
error.

             cout.write(buf.data(), len);
         }

----------------------------------------
Server:

         while (true) {

             tcp::socket socket(io_service);
             acceptor.accept(socket);

 
///////////////////////////////////////////////////////////////////////////////////

             boost::asio::streambuf      buf;
             boost::system::error_code   error;

             // read till end-of-args marker
             boost::asio::read_until(socket, buf, "\n\n");

             // extract args from buf
             std::istream net_in(&buf);

             while (getline(net_in, next_line)) {

                 if (next_line.length()) client_argv.push_back(next_line);
             }

             if (debug()) cout << client_argv.size() << " arguments 
received by server" << endl;

 
///////////////////////////////////////////////////////////////////////////////////

             ostringstream response;

             it_takes_two_to_tango(client_argv, tx, db, response);
             client_argv.clear();

             string message = response.str();

             // if (debug()) cout << "Deliver to server:" << endl << 
message << endl;

             boost::system::error_code ignored_error;
             boost::asio::write(socket, boost::asio::buffer(message), 
boost::asio::transfer_all(), ignored_error);
         }
     }