| // |
| // async_client.cpp |
| // ~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #include <iostream> |
| #include <istream> |
| #include <ostream> |
| #include <string> |
| #include <boost/asio.hpp> |
| #include <boost/bind.hpp> |
| |
| using boost::asio::ip::tcp; |
| |
| class client |
| { |
| public: |
| client(boost::asio::io_service& io_service, |
| const std::string& server, const std::string& path) |
| : resolver_(io_service), |
| socket_(io_service) |
| { |
| // Form the request. We specify the "Connection: close" header so that the |
| // server will close the socket after transmitting the response. This will |
| // allow us to treat all data up until the EOF as the content. |
| std::ostream request_stream(&request_); |
| request_stream << "GET " << path << " HTTP/1.0\r\n"; |
| request_stream << "Host: " << server << "\r\n"; |
| request_stream << "Accept: */*\r\n"; |
| request_stream << "Connection: close\r\n\r\n"; |
| |
| // Start an asynchronous resolve to translate the server and service names |
| // into a list of endpoints. |
| tcp::resolver::query query(server, "http"); |
| resolver_.async_resolve(query, |
| boost::bind(&client::handle_resolve, this, |
| boost::asio::placeholders::error, |
| boost::asio::placeholders::iterator)); |
| } |
| |
| private: |
| void handle_resolve(const boost::system::error_code& err, |
| tcp::resolver::iterator endpoint_iterator) |
| { |
| if (!err) |
| { |
| // Attempt a connection to the first endpoint in the list. Each endpoint |
| // will be tried until we successfully establish a connection. |
| tcp::endpoint endpoint = *endpoint_iterator; |
| socket_.async_connect(endpoint, |
| boost::bind(&client::handle_connect, this, |
| boost::asio::placeholders::error, ++endpoint_iterator)); |
| } |
| else |
| { |
| std::cout << "Error: " << err.message() << "\n"; |
| } |
| } |
| |
| void handle_connect(const boost::system::error_code& err, |
| tcp::resolver::iterator endpoint_iterator) |
| { |
| if (!err) |
| { |
| // The connection was successful. Send the request. |
| boost::asio::async_write(socket_, request_, |
| boost::bind(&client::handle_write_request, this, |
| boost::asio::placeholders::error)); |
| } |
| else if (endpoint_iterator != tcp::resolver::iterator()) |
| { |
| // The connection failed. Try the next endpoint in the list. |
| socket_.close(); |
| tcp::endpoint endpoint = *endpoint_iterator; |
| socket_.async_connect(endpoint, |
| boost::bind(&client::handle_connect, this, |
| boost::asio::placeholders::error, ++endpoint_iterator)); |
| } |
| else |
| { |
| std::cout << "Error: " << err.message() << "\n"; |
| } |
| } |
| |
| void handle_write_request(const boost::system::error_code& err) |
| { |
| if (!err) |
| { |
| // Read the response status line. The response_ streambuf will |
| // automatically grow to accommodate the entire line. The growth may be |
| // limited by passing a maximum size to the streambuf constructor. |
| boost::asio::async_read_until(socket_, response_, "\r\n", |
| boost::bind(&client::handle_read_status_line, this, |
| boost::asio::placeholders::error)); |
| } |
| else |
| { |
| std::cout << "Error: " << err.message() << "\n"; |
| } |
| } |
| |
| void handle_read_status_line(const boost::system::error_code& err) |
| { |
| if (!err) |
| { |
| // Check that response is OK. |
| std::istream response_stream(&response_); |
| std::string http_version; |
| response_stream >> http_version; |
| unsigned int status_code; |
| response_stream >> status_code; |
| std::string status_message; |
| std::getline(response_stream, status_message); |
| if (!response_stream || http_version.substr(0, 5) != "HTTP/") |
| { |
| std::cout << "Invalid response\n"; |
| return; |
| } |
| if (status_code != 200) |
| { |
| std::cout << "Response returned with status code "; |
| std::cout << status_code << "\n"; |
| return; |
| } |
| |
| // Read the response headers, which are terminated by a blank line. |
| boost::asio::async_read_until(socket_, response_, "\r\n\r\n", |
| boost::bind(&client::handle_read_headers, this, |
| boost::asio::placeholders::error)); |
| } |
| else |
| { |
| std::cout << "Error: " << err << "\n"; |
| } |
| } |
| |
| void handle_read_headers(const boost::system::error_code& err) |
| { |
| if (!err) |
| { |
| // Process the response headers. |
| std::istream response_stream(&response_); |
| std::string header; |
| while (std::getline(response_stream, header) && header != "\r") |
| std::cout << header << "\n"; |
| std::cout << "\n"; |
| |
| // Write whatever content we already have to output. |
| if (response_.size() > 0) |
| std::cout << &response_; |
| |
| // Start reading remaining data until EOF. |
| boost::asio::async_read(socket_, response_, |
| boost::asio::transfer_at_least(1), |
| boost::bind(&client::handle_read_content, this, |
| boost::asio::placeholders::error)); |
| } |
| else |
| { |
| std::cout << "Error: " << err << "\n"; |
| } |
| } |
| |
| void handle_read_content(const boost::system::error_code& err) |
| { |
| if (!err) |
| { |
| // Write all of the data that has been read so far. |
| std::cout << &response_; |
| |
| // Continue reading remaining data until EOF. |
| boost::asio::async_read(socket_, response_, |
| boost::asio::transfer_at_least(1), |
| boost::bind(&client::handle_read_content, this, |
| boost::asio::placeholders::error)); |
| } |
| else if (err != boost::asio::error::eof) |
| { |
| std::cout << "Error: " << err << "\n"; |
| } |
| } |
| |
| tcp::resolver resolver_; |
| tcp::socket socket_; |
| boost::asio::streambuf request_; |
| boost::asio::streambuf response_; |
| }; |
| |
| int main(int argc, char* argv[]) |
| { |
| try |
| { |
| if (argc != 3) |
| { |
| std::cout << "Usage: async_client <server> <path>\n"; |
| std::cout << "Example:\n"; |
| std::cout << " async_client www.boost.org /LICENSE_1_0.txt\n"; |
| return 1; |
| } |
| |
| boost::asio::io_service io_service; |
| client c(io_service, argv[1], argv[2]); |
| io_service.run(); |
| } |
| catch (std::exception& e) |
| { |
| std::cout << "Exception: " << e.what() << "\n"; |
| } |
| |
| return 0; |
| } |