boost asio使用

例子

void TestHttps(const char *host)
{
    boost::asio::io_service io;
    ip::tcp::resolver resolver(io); // handle DNS ?
    ip::tcp::resolver::query query(host, "443");
    boost::asio::ssl::context ctx(boost::asio::ssl::context::sslv23);
    boost::asio::ssl::stream<boost::asio::ip::tcp::socket> sock(io, ctx);
    boost::asio::streambuf response;
    response.prepare(100);
    resolver.async_resolve(query, [&](const boost::system::error_code &ec, ip::tcp::resolver::iterator iter)
                           {
            printf("resolve %s", ec.message().c_str());
            if (iter != ip::tcp::resolver::iterator())
            {
                /* code */
            async_connect(sock.lowest_layer(), iter, [&](const boost::system::error_code &ec2, ip::tcp::resolver::iterator iter2)
                          {
                            printf("connect %s %s", iter2->endpoint().address().to_string().c_str(),  ec2.message().c_str());
                            if (!ec2)
                            {
                                //ssl建连
                                sock.async_handshake(boost::asio::ssl::stream_base::client, [&](const boost::system::error_code &ec3)
                                                     {

                                    printf("ssl handshake %s", ec3.message().c_str());
                                    if (!ec3)
                                    {
                                        //发送http请求
                                        string req = "GET / HTTP/1.1\r\nAccept: */*\r\nHost: " + query.host_name() + "\r\n\r\n";
                                        printf("send http request \n%s", req.c_str());
                                        boost::asio::async_write(sock, boost::asio::buffer(req.c_str(), req.size()), [&](const boost::system::error_code &ec4, std::size_t bytes_transferred)
                                                                 {
                                                                     printf("send http %s,bytes_transferred:%d", ec4.message().c_str(),bytes_transferred);
                                                                     if (bytes_transferred > 0)
                                                                     {
                                                                         //接收http返回
                                                                         boost::asio::async_read(sock, response, [&](const boost::system::error_code &ec5, std::size_t bytes_transferred)
                                                                                                 {
                                                                                                     printf("recv http %s,bytes_transferred:%d", ec5.message().c_str(), bytes_transferred);
                                                                                                     if (bytes_transferred > 0)
                                                                                                     {
                                                                                                         //printf("recv http content:%s", response.data().);
                                                                                                     } });
                                                                     }
                                                                     });
                                    } });
                            }
                          });
            }

            while (iter != ip::tcp::resolver::iterator())
            {
                printf("resolve %s\n", iter->endpoint().address().to_string().c_str());
                ++iter;
            } });

    io.run();
    printf("io_service release\n");
}