# Crow: /home/farook/cppsrv/crow-0.3-fordoc/include/crow/websocket.h Source File

websocket.h
#pragma once
#include <boost/algorithm/string/predicate.hpp>
#include <boost/array.hpp>
#include "crow/socket_adaptors.h"
#include "crow/http_request.h"
#include "crow/TinySHA1.hpp"
namespace crow
{
namespace websocket
{
enum class WebSocketReadState
{
MiniHeader,
Len16,
Len64,
Mask,
Payload,
};
///A base class for websocket connection.
struct connection
{
virtual void send_binary(const std::string& msg) = 0;
virtual void send_text(const std::string& msg) = 0;
virtual void send_ping(const std::string& msg) = 0;
virtual void send_pong(const std::string& msg) = 0;
virtual void close(const std::string& msg = "quit") = 0;
virtual ~connection(){}
void userdata(void* u) { userdata_ = u; }
void* userdata() { return userdata_; }
private:
void* userdata_;
};
// 0 1 2 3 -byte
// 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 -bit
// +-+-+-+-+-------+-+-------------+-------------------------------+
// |F|R|R|R| opcode|M| Payload len | Extended payload length |
// |I|S|S|S| (4) |A| (7) | (16/64) |
// |N|V|V|V| |S| | (if payload len==126/127) |
// | |1|2|3| |K| | |
// +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
// | Extended payload length continued, if payload len == 127 |
// + - - - - - - - - - - - - - - - +-------------------------------+
// | |Masking-key, if MASK set to 1 |
// +-------------------------------+-------------------------------+
// | Masking-key (continued) | Payload Data |
// +-------------------------------- - - - - - - - - - - - - - - - +
// : Payload Data continued ... :
// + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
// | Payload Data continued ... |
// +---------------------------------------------------------------+
/// A websocket connection.
template <typename Adaptor>
class Connection : public connection
{
public:
/// Constructor for a connection.
///
/// Requires a request with an "Upgrade: websocket" header.<br>
/// Automatically handles the handshake.
Connection(const crow::request& req, Adaptor&& adaptor,
std::function<void(crow::websocket::connection&)> open_handler,
std::function<void(crow::websocket::connection&, const std::string&, bool)> message_handler,
std::function<void(crow::websocket::connection&, const std::string&)> close_handler,
std::function<void(crow::websocket::connection&)> error_handler,
std::function<bool(const crow::request&)> accept_handler)
: adaptor_(std::move(adaptor)), open_handler_(std::move(open_handler)), message_handler_(std::move(message_handler)), close_handler_(std::move(close_handler)), error_handler_(std::move(error_handler))
, accept_handler_(std::move(accept_handler))
{
if (!boost::iequals(req.get_header_value("upgrade"), "websocket"))
{
adaptor.close();
delete this;
return;
}
if (accept_handler_)
{
if (!accept_handler_(req))
{
adaptor.close();
delete this;
return;
}
}
// Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
// Sec-WebSocket-Version: 13
std::string magic = req.get_header_value("Sec-WebSocket-Key") + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
sha1::SHA1 s;
s.processBytes(magic.data(), magic.size());
uint8_t digest[20];
s.getDigestBytes(digest);
start(crow::utility::base64encode((char*)digest, 20));
}
/// Send data through the socket.
template<typename CompletionHandler>
void dispatch(CompletionHandler handler)
{
adaptor_.get_io_service().dispatch(handler);
}
/// Send data through the socket and return immediately.
template<typename CompletionHandler>
void post(CompletionHandler handler)
{
adaptor_.get_io_service().post(handler);
}
/// Send a "Ping" message.
///
/// Usually invoked to check if the other point is still online.
void send_ping(const std::string& msg) override
{
dispatch([this, msg]{
auto header = build_header(0x9, msg.size());
write_buffers_.emplace_back(std::move(header));
write_buffers_.emplace_back(msg);
do_write();
});
}
/// Send a "Pong" message.
///
/// Usually automatically invoked as a response to a "Ping" message.
void send_pong(const std::string& msg) override
{
dispatch([this, msg]{
auto header = build_header(0xA, msg.size());
write_buffers_.emplace_back(std::move(header));
write_buffers_.emplace_back(msg);
do_write();
});
}
/// Send a binary encoded message.
void send_binary(const std::string& msg) override
{
dispatch([this, msg]{
auto header = build_header(2, msg.size());
write_buffers_.emplace_back(std::move(header));
write_buffers_.emplace_back(msg);
do_write();
});
}
/// Send a plaintext message.
void send_text(const std::string& msg) override
{
dispatch([this, msg]{
auto header = build_header(1, msg.size());
write_buffers_.emplace_back(std::move(header));
write_buffers_.emplace_back(msg);
do_write();
});
}
/// Send a close signal.
///
/// Sets a flag to destroy the object once the message is sent.
void close(const std::string& msg) override
{
dispatch([this, msg]{
has_sent_close_ = true;
if (has_recv_close_ && !is_close_handler_called_)
{
is_close_handler_called_ = true;
if (close_handler_)
close_handler_(*this, msg);
}
auto header = build_header(0x8, msg.size());
write_buffers_.emplace_back(std::move(header));
write_buffers_.emplace_back(msg);
do_write();
});
}
protected:
/// Generate the websocket headers using an opcode and the message size (in bytes).
std::string build_header(int opcode, size_t size)
{
char buf[2+8] = "\x80\x00";
buf[0] += opcode;
if (size < 126)
{
buf[1] += static_cast<char>(size);
return {buf, buf+2};
}
else if (size < 0x10000)
{
buf[1] += 126;
*(uint16_t*)(buf+2) = htons(static_cast<uint16_t>(size));
return {buf, buf+4};
}
else
{
buf[1] += 127;
*reinterpret_cast<uint64_t*>(buf+2) = ((1==htonl(1)) ? static_cast<uint64_t>(size) : (static_cast<uint64_t>(htonl((size) & 0xFFFFFFFF)) << 32) | htonl(static_cast<uint64_t>(size) >> 32));
return {buf, buf+10};
}
}
/// Send the HTTP upgrade response.
///
/// Finishes the handshake process, then starts reading messages from the socket.
void start(std::string&& hello)
{
static std::string header = "HTTP/1.1 101 Switching Protocols\r\n"
"Upgrade: websocket\r\n"
"Connection: Upgrade\r\n"
"Sec-WebSocket-Accept: ";
static std::string crlf = "\r\n";
write_buffers_.emplace_back(header);
write_buffers_.emplace_back(std::move(hello));
write_buffers_.emplace_back(crlf);
write_buffers_.emplace_back(crlf);
do_write();
if (open_handler_)
open_handler_(*this);
do_read();
}
/// Read a websocket message.
///
/// Involves:<br>
/// Handling headers (opcodes, size).<br>
/// Unmasking the payload.<br>
/// Reading the actual payload.<br>
void do_read()
{
is_reading = true;
switch(state_)
{
case WebSocketReadState::MiniHeader:
{
mini_header_ = 0;
//boost::asio::async_read(adaptor_.socket(), boost::asio::buffer(&mini_header_, 1),
adaptor_.socket().async_read_some(boost::asio::buffer(&mini_header_, 2),
[this](const boost::system::error_code& ec, std::size_t
#ifdef CROW_ENABLE_DEBUG
bytes_transferred
#endif
)
{
is_reading = false;
mini_header_ = ntohs(mini_header_);
#ifdef CROW_ENABLE_DEBUG
if (!ec && bytes_transferred != 2)
{
throw std::runtime_error("WebSocket:MiniHeader:async_read fail:asio bug?");
}
#endif
if (!ec)
{
if ((mini_header_ & 0x80) == 0x80)
has_mask_ = true;
if ((mini_header_ & 0x7f) == 127)
{
state_ = WebSocketReadState::Len64;
}
else if ((mini_header_ & 0x7f) == 126)
{
state_ = WebSocketReadState::Len16;
}
else
{
remaining_length_ = mini_header_ & 0x7f;
state_ = WebSocketReadState::Mask;
}
do_read();
}
else
{
close_connection_ = true;
adaptor_.close();
if (error_handler_)
error_handler_(*this);
check_destroy();
}
});
}
break;
case WebSocketReadState::Len16:
{
remaining_length_ = 0;
remaining_length16_ = 0;
boost::asio::async_read(adaptor_.socket(), boost::asio::buffer(&remaining_length16_, 2),
[this](const boost::system::error_code& ec, std::size_t
#ifdef CROW_ENABLE_DEBUG
bytes_transferred
#endif
)
{
is_reading = false;
remaining_length16_ = ntohs(remaining_length16_);
remaining_length_ = remaining_length16_;
#ifdef CROW_ENABLE_DEBUG
if (!ec && bytes_transferred != 2)
{
throw std::runtime_error("WebSocket:Len16:async_read fail:asio bug?");
}
#endif
if (!ec)
{
state_ = WebSocketReadState::Mask;
do_read();
}
else
{
close_connection_ = true;
adaptor_.close();
if (error_handler_)
error_handler_(*this);
check_destroy();
}
});
}
break;
case WebSocketReadState::Len64:
{
boost::asio::async_read(adaptor_.socket(), boost::asio::buffer(&remaining_length_, 8),
[this](const boost::system::error_code& ec, std::size_t
#ifdef CROW_ENABLE_DEBUG
bytes_transferred
#endif
)
{
is_reading = false;
remaining_length_ = ((1==ntohl(1)) ? (remaining_length_) : (static_cast<uint64_t>(ntohl((remaining_length_) & 0xFFFFFFFF)) << 32) | ntohl((remaining_length_) >> 32));
#ifdef CROW_ENABLE_DEBUG
if (!ec && bytes_transferred != 8)
{
throw std::runtime_error("WebSocket:Len16:async_read fail:asio bug?");
}
#endif
if (!ec)
{
state_ = WebSocketReadState::Mask;
do_read();
}
else
{
close_connection_ = true;
adaptor_.close();
if (error_handler_)
error_handler_(*this);
check_destroy();
}
});
}
break;
case WebSocketReadState::Mask:
if (has_mask_)
{
boost::asio::async_read(adaptor_.socket(), boost::asio::buffer((char*)&mask_, 4),
[this](const boost::system::error_code& ec, std::size_t
#ifdef CROW_ENABLE_DEBUG
bytes_transferred
#endif
)
{
is_reading = false;
#ifdef CROW_ENABLE_DEBUG
if (!ec && bytes_transferred != 4)
{
throw std::runtime_error("WebSocket:Mask:async_read fail:asio bug?");
}
#endif
if (!ec)
{
state_ = WebSocketReadState::Payload;
do_read();
}
else
{
close_connection_ = true;
if (error_handler_)
error_handler_(*this);
adaptor_.close();
}
});
}
else
{
state_ = WebSocketReadState::Payload;
do_read();
}
break;
case WebSocketReadState::Payload:
{
auto to_read = static_cast<std::uint64_t>(buffer_.size());
if (remaining_length_ < to_read)
to_read = remaining_length_;
adaptor_.socket().async_read_some(boost::asio::buffer(buffer_, static_cast<std::size_t>(to_read)),
[this](const boost::system::error_code& ec, std::size_t bytes_transferred)
{
is_reading = false;
if (!ec)
{
fragment_.insert(fragment_.end(), buffer_.begin(), buffer_.begin() + bytes_transferred);
remaining_length_ -= bytes_transferred;
if (remaining_length_ == 0)
{
handle_fragment();
state_ = WebSocketReadState::MiniHeader;
do_read();
}
else
do_read();
}
else
{
close_connection_ = true;
if (error_handler_)
error_handler_(*this);
adaptor_.close();
}
});
}
break;
}
}
/// Check if the FIN bit is set.
bool is_FIN()
{
return mini_header_ & 0x8000;
}
/// Extract the opcode from the header.
int opcode()
{
return (mini_header_ & 0x0f00) >> 8;
}
/// Process the payload fragment.
///
/// Unmasks the fragment, checks the opcode, merges fragments into 1 message body, and calls the appropriate handler.
void handle_fragment()
{
if (has_mask_)
{
for(decltype(fragment_.length()) i = 0; i < fragment_.length(); i ++)
{
fragment_[i] ^= ((char*)&mask_)[i%4];
}
}
switch(opcode())
{
case 0: // Continuation
{
message_ += fragment_;
if (is_FIN())
{
if (message_handler_)
message_handler_(*this, message_, is_binary_);
message_.clear();
}
}
break;
case 1: // Text
{
is_binary_ = false;
message_ += fragment_;
if (is_FIN())
{
if (message_handler_)
message_handler_(*this, message_, is_binary_);
message_.clear();
}
}
break;
case 2: // Binary
{
is_binary_ = true;
message_ += fragment_;
if (is_FIN())
{
if (message_handler_)
message_handler_(*this, message_, is_binary_);
message_.clear();
}
}
break;
case 0x8: // Close
{
has_recv_close_ = true;
if (!has_sent_close_)
{
close(fragment_);
}
else
{
adaptor_.close();
close_connection_ = true;
if (!is_close_handler_called_)
{
if (close_handler_)
close_handler_(*this, fragment_);
is_close_handler_called_ = true;
}
check_destroy();
}
}
break;
case 0x9: // Ping
{
send_pong(fragment_);
}
break;
case 0xA: // Pong
{
pong_received_ = true;
}
break;
}
fragment_.clear();
}
/// Send the buffers' data through the socket.
///
/// Also destroyes the object if the Close flag is set.
void do_write()
{
if (sending_buffers_.empty())
{
sending_buffers_.swap(write_buffers_);
std::vector<boost::asio::const_buffer> buffers;
buffers.reserve(sending_buffers_.size());
for(auto& s:sending_buffers_)
{
buffers.emplace_back(boost::asio::buffer(s));
}
boost::asio::async_write(adaptor_.socket(), buffers,
[&](const boost::system::error_code& ec, std::size_t /*bytes_transferred*/)
{
sending_buffers_.clear();
if (!ec && !close_connection_)
{
if (!write_buffers_.empty())
do_write();
if (has_sent_close_)
close_connection_ = true;
}
else
{
close_connection_ = true;
check_destroy();
}
});
}
}
/// Destroy the Connection.
void check_destroy()
{
//if (has_sent_close_ && has_recv_close_)
if (!is_close_handler_called_)
if (close_handler_)
close_handler_(*this, "uncleanly");
if (sending_buffers_.empty() && !is_reading)
delete this;
}
private:
Adaptor adaptor_;
std::vector<std::string> sending_buffers_;
std::vector<std::string> write_buffers_;
boost::array<char, 4096> buffer_;
bool is_binary_;
std::string message_;
std::string fragment_;
WebSocketReadState state_{WebSocketReadState::MiniHeader};
uint16_t remaining_length16_{0};
uint64_t remaining_length_{0};
bool close_connection_{false};
bool is_reading{false};
bool has_mask_{false};
uint32_t mask_;
uint16_t mini_header_;
bool has_sent_close_{false};
bool has_recv_close_{false};
bool error_occured_{false};
bool pong_received_{false};
bool is_close_handler_called_{false};
std::function<void(crow::websocket::connection&)> open_handler_;
std::function<void(crow::websocket::connection&, const std::string&, bool)> message_handler_;
std::function<void(crow::websocket::connection&, const std::string&)> close_handler_;
std::function<void(crow::websocket::connection&)> error_handler_;
std::function<bool(const crow::request&)> accept_handler_;
};
}
}
crow::websocket::Connection
A websocket connection.
Definition: websocket.h:60
crow::websocket::Connection::check_destroy
void check_destroy()
Destroy the Connection.
Definition: websocket.h:579
crow::websocket::Connection::close
void close(const std::string &msg) override
Send a close signal.
Definition: websocket.h:171
crow::websocket::Connection::start
void start(std::string &&hello)
Send the HTTP upgrade response.
Definition: websocket.h:218
crow::websocket::Connection::handle_fragment
void handle_fragment()
Process the payload fragment.
Definition: websocket.h:461
crow::websocket::Connection::opcode
int opcode()
Extract the opcode from the header.
Definition: websocket.h:452
crow::websocket::Connection::send_ping
void send_ping(const std::string &msg) override
Send a "Ping" message.
Definition: websocket.h:121
crow::websocket::Connection::do_write
void do_write()
Send the buffers' data through the socket.
Definition: websocket.h:547
crow::websocket::Connection::dispatch
void dispatch(CompletionHandler handler)
Send data through the socket.
Definition: websocket.h:105
crow::websocket::Connection::Connection
Connection(const crow::request &req, Adaptor &&adaptor, std::function< void(crow::websocket::connection &)> open_handler, std::function< void(crow::websocket::connection &, const std::string &, bool)> message_handler, std::function< void(crow::websocket::connection &, const std::string &)> close_handler, std::function< void(crow::websocket::connection &)> error_handler, std::function< bool(const crow::request &)> accept_handler)
Constructor for a connection.
Definition: websocket.h:67
crow::websocket::Connection::send_text
void send_text(const std::string &msg) override
Send a plaintext message.
Definition: websocket.h:157
crow::websocket::Connection::post
void post(CompletionHandler handler)
Send data through the socket and return immediately.
Definition: websocket.h:112
crow::websocket::Connection::build_header
std::string build_header(int opcode, size_t size)
Generate the websocket headers using an opcode and the message size (in bytes).
Definition: websocket.h:191
crow::websocket::Connection::do_read
void do_read()
Read a websocket message.
Definition: websocket.h:242
crow::websocket::Connection::send_binary
void send_binary(const std::string &msg) override
Send a binary encoded message.
Definition: websocket.h:146
crow::websocket::Connection::send_pong
void send_pong(const std::string &msg) override
Send a "Pong" message.
Definition: websocket.h:135
crow::websocket::Connection::is_FIN
bool is_FIN()
Check if the FIN bit is set.
Definition: websocket.h:446
crow::request
An HTTP request.
Definition: http_request.h:27
crow::websocket::connection
A base class for websocket connection.
Definition: websocket.h:23