beast/example/websocket/server/chat-multi/http_session.cpp
2019-03-29 20:42:44 -07:00

372 lines
11 KiB
C++

//
// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail 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)
//
// Official repository: https://github.com/vinniefalco/CppCon2018
//
#include "http_session.hpp"
#include "websocket_session.hpp"
#include <boost/config.hpp>
#include <iostream>
#define BOOST_NO_CXX14_GENERIC_LAMBDAS
//------------------------------------------------------------------------------
// Return a reasonable mime type based on the extension of a file.
beast::string_view
mime_type(beast::string_view path)
{
using beast::iequals;
auto const ext = [&path]
{
auto const pos = path.rfind(".");
if(pos == beast::string_view::npos)
return beast::string_view{};
return path.substr(pos);
}();
if(iequals(ext, ".htm")) return "text/html";
if(iequals(ext, ".html")) return "text/html";
if(iequals(ext, ".php")) return "text/html";
if(iequals(ext, ".css")) return "text/css";
if(iequals(ext, ".txt")) return "text/plain";
if(iequals(ext, ".js")) return "application/javascript";
if(iequals(ext, ".json")) return "application/json";
if(iequals(ext, ".xml")) return "application/xml";
if(iequals(ext, ".swf")) return "application/x-shockwave-flash";
if(iequals(ext, ".flv")) return "video/x-flv";
if(iequals(ext, ".png")) return "image/png";
if(iequals(ext, ".jpe")) return "image/jpeg";
if(iequals(ext, ".jpeg")) return "image/jpeg";
if(iequals(ext, ".jpg")) return "image/jpeg";
if(iequals(ext, ".gif")) return "image/gif";
if(iequals(ext, ".bmp")) return "image/bmp";
if(iequals(ext, ".ico")) return "image/vnd.microsoft.icon";
if(iequals(ext, ".tiff")) return "image/tiff";
if(iequals(ext, ".tif")) return "image/tiff";
if(iequals(ext, ".svg")) return "image/svg+xml";
if(iequals(ext, ".svgz")) return "image/svg+xml";
return "application/text";
}
// Append an HTTP rel-path to a local filesystem path.
// The returned path is normalized for the platform.
std::string
path_cat(
beast::string_view base,
beast::string_view path)
{
if(base.empty())
return std::string(path);
std::string result(base);
#ifdef BOOST_MSVC
char constexpr path_separator = '\\';
if(result.back() == path_separator)
result.resize(result.size() - 1);
result.append(path.data(), path.size());
for(auto& c : result)
if(c == '/')
c = path_separator;
#else
char constexpr path_separator = '/';
if(result.back() == path_separator)
result.resize(result.size() - 1);
result.append(path.data(), path.size());
#endif
return result;
}
// This function produces an HTTP response for the given
// request. The type of the response object depends on the
// contents of the request, so the interface requires the
// caller to pass a generic lambda for receiving the response.
template<
class Body, class Allocator,
class Send>
void
handle_request(
beast::string_view doc_root,
http::request<Body, http::basic_fields<Allocator>>&& req,
Send&& send)
{
// Returns a bad request response
auto const bad_request =
[&req](beast::string_view why)
{
http::response<http::string_body> res{http::status::bad_request, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, "text/html");
res.keep_alive(req.keep_alive());
res.body() = std::string(why);
res.prepare_payload();
return res;
};
// Returns a not found response
auto const not_found =
[&req](beast::string_view target)
{
http::response<http::string_body> res{http::status::not_found, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, "text/html");
res.keep_alive(req.keep_alive());
res.body() = "The resource '" + std::string(target) + "' was not found.";
res.prepare_payload();
return res;
};
// Returns a server error response
auto const server_error =
[&req](beast::string_view what)
{
http::response<http::string_body> res{http::status::internal_server_error, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, "text/html");
res.keep_alive(req.keep_alive());
res.body() = "An error occurred: '" + std::string(what) + "'";
res.prepare_payload();
return res;
};
// Make sure we can handle the method
if( req.method() != http::verb::get &&
req.method() != http::verb::head)
return send(bad_request("Unknown HTTP-method"));
// Request path must be absolute and not contain "..".
if( req.target().empty() ||
req.target()[0] != '/' ||
req.target().find("..") != beast::string_view::npos)
return send(bad_request("Illegal request-target"));
// Build the path to the requested file
std::string path = path_cat(doc_root, req.target());
if(req.target().back() == '/')
path.append("index.html");
// Attempt to open the file
beast::error_code ec;
http::file_body::value_type body;
body.open(path.c_str(), beast::file_mode::scan, ec);
// Handle the case where the file doesn't exist
if(ec == boost::system::errc::no_such_file_or_directory)
return send(not_found(req.target()));
// Handle an unknown error
if(ec)
return send(server_error(ec.message()));
// Cache the size since we need it after the move
auto const size = body.size();
// Respond to HEAD request
if(req.method() == http::verb::head)
{
http::response<http::empty_body> res{http::status::ok, req.version()};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, mime_type(path));
res.content_length(size);
res.keep_alive(req.keep_alive());
return send(std::move(res));
}
// Respond to GET request
http::response<http::file_body> res{
std::piecewise_construct,
std::make_tuple(std::move(body)),
std::make_tuple(http::status::ok, req.version())};
res.set(http::field::server, BOOST_BEAST_VERSION_STRING);
res.set(http::field::content_type, mime_type(path));
res.content_length(size);
res.keep_alive(req.keep_alive());
return send(std::move(res));
}
//------------------------------------------------------------------------------
struct http_session::send_lambda
{
http_session& self_;
explicit
send_lambda(http_session& self)
: self_(self)
{
}
template<bool isRequest, class Body, class Fields>
void
operator()(http::message<isRequest, Body, Fields>&& msg) const
{
// The lifetime of the message has to extend
// for the duration of the async operation so
// we use a shared_ptr to manage it.
auto sp = boost::make_shared<
http::message<isRequest, Body, Fields>>(std::move(msg));
// Write the response
auto self = self_.shared_from_this();
http::async_write(
self_.stream_,
*sp,
[self, sp](beast::error_code ec, std::size_t bytes)
{
self->on_write(ec, bytes, sp->need_eof());
});
}
};
//------------------------------------------------------------------------------
http_session::
http_session(
tcp::socket&& socket,
boost::shared_ptr<shared_state> const& state)
: stream_(std::move(socket))
, state_(state)
{
}
void
http_session::
run()
{
do_read();
}
// Report a failure
void
http_session::
fail(beast::error_code ec, char const* what)
{
// Don't report on canceled operations
if(ec == net::error::operation_aborted)
return;
std::cerr << what << ": " << ec.message() << "\n";
}
void
http_session::
do_read()
{
// Construct a new parser for each message
parser_.emplace();
// Apply a reasonable limit to the allowed size
// of the body in bytes to prevent abuse.
parser_->body_limit(10000);
// Set the timeout.
stream_.expires_after(std::chrono::seconds(30));
// Read a request
http::async_read(
stream_,
buffer_,
parser_->get(),
beast::bind_front_handler(
&http_session::on_read,
shared_from_this()));
}
void
http_session::
on_read(beast::error_code ec, std::size_t)
{
// This means they closed the connection
if(ec == http::error::end_of_stream)
{
stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
return;
}
// Handle the error, if any
if(ec)
return fail(ec, "read");
// See if it is a WebSocket Upgrade
if(websocket::is_upgrade(parser_->get()))
{
// Create a websocket session, transferring ownership
// of both the socket and the HTTP request.
boost::make_shared<websocket_session>(
stream_.release_socket(),
state_)->run(parser_->release());
return;
}
// Send the response
#ifndef BOOST_NO_CXX14_GENERIC_LAMBDAS
//
// The following code requires generic
// lambdas, available in C++14 and later.
//
handle_request(
state_->doc_root(),
std::move(req_),
[this](auto&& response)
{
// The lifetime of the message has to extend
// for the duration of the async operation so
// we use a shared_ptr to manage it.
using response_type = typename std::decay<decltype(response)>::type;
auto sp = boost::make_shared<response_type>(std::forward<decltype(response)>(response));
#if 0
// NOTE This causes an ICE in gcc 7.3
// Write the response
http::async_write(this->stream_, *sp,
[self = shared_from_this(), sp](
beast::error_code ec, std::size_t bytes)
{
self->on_write(ec, bytes, sp->need_eof());
});
#else
// Write the response
auto self = shared_from_this();
http::async_write(stream_, *sp,
[self, sp](
beast::error_code ec, std::size_t bytes)
{
self->on_write(ec, bytes, sp->need_eof());
});
#endif
});
#else
//
// This code uses the function object type send_lambda in
// place of a generic lambda which is not available in C++11
//
handle_request(
state_->doc_root(),
parser_->release(),
send_lambda(*this));
#endif
}
void
http_session::
on_write(beast::error_code ec, std::size_t, bool close)
{
// Handle the error, if any
if(ec)
return fail(ec, "write");
if(close)
{
// This means we should close the connection, usually because
// the response indicated the "Connection: close" semantic.
stream_.socket().shutdown(tcp::socket::shutdown_send, ec);
return;
}
// Read another request
do_read();
}