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https://github.com/CrowCpp/Crow.git
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705 lines
28 KiB
C++
705 lines
28 KiB
C++
#pragma once
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#include <array>
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#include "crow/logging.h"
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#include "crow/socket_adaptors.h"
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#include "crow/http_request.h"
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#include "crow/TinySHA1.hpp"
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#include "crow/utility.h"
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namespace crow
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{
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namespace websocket
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{
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enum class WebSocketReadState
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{
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MiniHeader,
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Len16,
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Len64,
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Mask,
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Payload,
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};
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/// A base class for websocket connection.
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struct connection
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{
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virtual void send_binary(std::string msg) = 0;
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virtual void send_text(std::string msg) = 0;
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virtual void send_ping(std::string msg) = 0;
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virtual void send_pong(std::string msg) = 0;
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virtual void close(std::string const& msg = "quit") = 0;
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virtual std::string get_remote_ip() = 0;
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virtual ~connection() = default;
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void userdata(void* u) { userdata_ = u; }
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void* userdata() { return userdata_; }
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private:
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void* userdata_;
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};
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// Modified version of the illustration in RFC6455 Section-5.2
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//
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//
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// 0 1 2 3 -byte
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// 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
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// +-+-+-+-+-------+-+-------------+-------------------------------+
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// |F|R|R|R| opcode|M| Payload len | Extended payload length |
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// |I|S|S|S| (4) |A| (7) | (16/64) |
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// |N|V|V|V| |S| | (if payload len==126/127) |
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// | |1|2|3| |K| | |
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// +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
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// | Extended payload length continued, if payload len == 127 |
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// + - - - - - - - - - - - - - - - +-------------------------------+
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// | |Masking-key, if MASK set to 1 |
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// +-------------------------------+-------------------------------+
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// | Masking-key (continued) | Payload Data |
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// +-------------------------------- - - - - - - - - - - - - - - - +
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// : Payload Data continued ... :
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// + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
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// | Payload Data continued ... |
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// +---------------------------------------------------------------+
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//
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/// A websocket connection.
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template<typename Adaptor, typename Handler>
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class Connection : public connection
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{
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public:
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/// Constructor for a connection.
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///
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/// Requires a request with an "Upgrade: websocket" header.<br>
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/// Automatically handles the handshake.
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Connection(const crow::request& req, Adaptor&& adaptor, Handler* handler, uint64_t max_payload,
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std::function<void(crow::websocket::connection&)> open_handler,
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std::function<void(crow::websocket::connection&, const std::string&, bool)> message_handler,
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std::function<void(crow::websocket::connection&, const std::string&)> close_handler,
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std::function<void(crow::websocket::connection&, const std::string&)> error_handler,
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std::function<bool(const crow::request&, void**)> accept_handler):
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adaptor_(std::move(adaptor)),
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handler_(handler),
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max_payload_bytes_(max_payload),
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open_handler_(std::move(open_handler)),
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message_handler_(std::move(message_handler)),
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close_handler_(std::move(close_handler)),
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error_handler_(std::move(error_handler)),
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accept_handler_(std::move(accept_handler))
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{
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if (!utility::string_equals(req.get_header_value("upgrade"), "websocket"))
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{
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adaptor.close();
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handler_->remove_websocket(this);
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delete this;
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return;
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}
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if (accept_handler_)
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{
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void* ud = nullptr;
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if (!accept_handler_(req, &ud))
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{
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adaptor.close();
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handler_->remove_websocket(this);
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delete this;
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return;
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}
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userdata(ud);
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}
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// Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
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// Sec-WebSocket-Version: 13
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std::string magic = req.get_header_value("Sec-WebSocket-Key") + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
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sha1::SHA1 s;
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s.processBytes(magic.data(), magic.size());
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uint8_t digest[20];
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s.getDigestBytes(digest);
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start(crow::utility::base64encode((unsigned char*)digest, 20));
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}
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/// Send data through the socket.
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template<typename CompletionHandler>
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void dispatch(CompletionHandler&& handler)
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{
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asio::dispatch(adaptor_.get_io_service(), std::forward<CompletionHandler>(handler));
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}
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/// Send data through the socket and return immediately.
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template<typename CompletionHandler>
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void post(CompletionHandler&& handler)
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{
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asio::post(adaptor_.get_io_service(), std::forward<CompletionHandler>(handler));
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}
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/// Send a "Ping" message.
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///
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/// Usually invoked to check if the other point is still online.
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void send_ping(std::string msg) override
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{
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send_data(0x9, std::move(msg));
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}
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/// Send a "Pong" message.
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///
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/// Usually automatically invoked as a response to a "Ping" message.
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void send_pong(std::string msg) override
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{
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send_data(0xA, std::move(msg));
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}
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/// Send a binary encoded message.
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void send_binary(std::string msg) override
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{
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send_data(0x2, std::move(msg));
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}
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/// Send a plaintext message.
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void send_text(std::string msg) override
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{
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send_data(0x1, std::move(msg));
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}
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/// Send a close signal.
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///
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/// Sets a flag to destroy the object once the message is sent.
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void close(std::string const& msg) override
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{
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dispatch([this, msg]() mutable {
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has_sent_close_ = true;
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if (has_recv_close_ && !is_close_handler_called_)
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{
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is_close_handler_called_ = true;
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if (close_handler_)
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close_handler_(*this, msg);
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}
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auto header = build_header(0x8, msg.size());
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write_buffers_.emplace_back(std::move(header));
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write_buffers_.emplace_back(msg);
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do_write();
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});
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}
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std::string get_remote_ip() override
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{
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return adaptor_.remote_endpoint().address().to_string();
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}
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void set_max_payload_size(uint64_t payload)
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{
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max_payload_bytes_ = payload;
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}
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protected:
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/// Generate the websocket headers using an opcode and the message size (in bytes).
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std::string build_header(int opcode, size_t size)
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{
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char buf[2 + 8] = "\x80\x00";
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buf[0] += opcode;
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if (size < 126)
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{
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buf[1] += static_cast<char>(size);
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return {buf, buf + 2};
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}
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else if (size < 0x10000)
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{
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buf[1] += 126;
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*(uint16_t*)(buf + 2) = htons(static_cast<uint16_t>(size));
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return {buf, buf + 4};
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}
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else
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{
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buf[1] += 127;
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*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));
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return {buf, buf + 10};
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}
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}
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/// Send the HTTP upgrade response.
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///
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/// Finishes the handshake process, then starts reading messages from the socket.
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void start(std::string&& hello)
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{
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static const std::string header =
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"HTTP/1.1 101 Switching Protocols\r\n"
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"Upgrade: websocket\r\n"
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"Connection: Upgrade\r\n"
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"Sec-WebSocket-Accept: ";
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write_buffers_.emplace_back(header);
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write_buffers_.emplace_back(std::move(hello));
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write_buffers_.emplace_back(crlf);
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write_buffers_.emplace_back(crlf);
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do_write();
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if (open_handler_)
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open_handler_(*this);
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do_read();
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}
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/// Read a websocket message.
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///
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/// Involves:<br>
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/// Handling headers (opcodes, size).<br>
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/// Unmasking the payload.<br>
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/// Reading the actual payload.<br>
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void do_read()
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{
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if (has_sent_close_ && has_recv_close_)
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{
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close_connection_ = true;
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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check_destroy();
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return;
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}
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is_reading = true;
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switch (state_)
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{
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case WebSocketReadState::MiniHeader:
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{
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mini_header_ = 0;
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//asio::async_read(adaptor_.socket(), asio::buffer(&mini_header_, 1),
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adaptor_.socket().async_read_some(
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asio::buffer(&mini_header_, 2),
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[this](const asio::error_code& ec, std::size_t
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#ifdef CROW_ENABLE_DEBUG
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bytes_transferred
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#endif
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)
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{
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is_reading = false;
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mini_header_ = ntohs(mini_header_);
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#ifdef CROW_ENABLE_DEBUG
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if (!ec && bytes_transferred != 2)
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{
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throw std::runtime_error("WebSocket:MiniHeader:async_read fail:asio bug?");
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}
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#endif
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if (!ec)
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{
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if ((mini_header_ & 0x80) == 0x80)
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has_mask_ = true;
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else //if the websocket specification is enforced and the message isn't masked, terminate the connection
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{
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#ifndef CROW_ENFORCE_WS_SPEC
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has_mask_ = false;
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#else
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close_connection_ = true;
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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if (error_handler_)
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error_handler_(*this, "Client connection not masked.");
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check_destroy();
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#endif
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}
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if ((mini_header_ & 0x7f) == 127)
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{
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state_ = WebSocketReadState::Len64;
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}
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else if ((mini_header_ & 0x7f) == 126)
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{
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state_ = WebSocketReadState::Len16;
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}
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else
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{
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remaining_length_ = mini_header_ & 0x7f;
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state_ = WebSocketReadState::Mask;
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}
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do_read();
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}
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else
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{
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close_connection_ = true;
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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if (error_handler_)
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error_handler_(*this, ec.message());
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check_destroy();
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}
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});
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}
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break;
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case WebSocketReadState::Len16:
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{
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remaining_length_ = 0;
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remaining_length16_ = 0;
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asio::async_read(
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adaptor_.socket(), asio::buffer(&remaining_length16_, 2),
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[this](const asio::error_code& ec, std::size_t
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#ifdef CROW_ENABLE_DEBUG
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bytes_transferred
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#endif
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) {
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is_reading = false;
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remaining_length16_ = ntohs(remaining_length16_);
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remaining_length_ = remaining_length16_;
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#ifdef CROW_ENABLE_DEBUG
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if (!ec && bytes_transferred != 2)
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{
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throw std::runtime_error("WebSocket:Len16:async_read fail:asio bug?");
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}
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#endif
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if (!ec)
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{
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state_ = WebSocketReadState::Mask;
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do_read();
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}
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else
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{
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close_connection_ = true;
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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if (error_handler_)
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error_handler_(*this, ec.message());
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check_destroy();
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}
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});
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}
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break;
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case WebSocketReadState::Len64:
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{
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asio::async_read(
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adaptor_.socket(), asio::buffer(&remaining_length_, 8),
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[this](const asio::error_code& ec, std::size_t
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#ifdef CROW_ENABLE_DEBUG
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bytes_transferred
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#endif
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) {
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is_reading = false;
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remaining_length_ = ((1 == ntohl(1)) ? (remaining_length_) : (static_cast<uint64_t>(ntohl((remaining_length_)&0xFFFFFFFF)) << 32) | ntohl((remaining_length_) >> 32));
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#ifdef CROW_ENABLE_DEBUG
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if (!ec && bytes_transferred != 8)
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{
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throw std::runtime_error("WebSocket:Len16:async_read fail:asio bug?");
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}
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#endif
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if (!ec)
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{
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state_ = WebSocketReadState::Mask;
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do_read();
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}
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else
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{
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close_connection_ = true;
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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if (error_handler_)
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error_handler_(*this, ec.message());
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check_destroy();
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}
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});
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}
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break;
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case WebSocketReadState::Mask:
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if (remaining_length_ > max_payload_bytes_)
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{
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close_connection_ = true;
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adaptor_.close();
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if (error_handler_)
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error_handler_(*this, "Message length exceeds maximum paylaod.");
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check_destroy();
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}
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else if (has_mask_)
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{
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asio::async_read(
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adaptor_.socket(), asio::buffer((char*)&mask_, 4),
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[this](const asio::error_code& ec, std::size_t
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#ifdef CROW_ENABLE_DEBUG
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bytes_transferred
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#endif
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) {
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is_reading = false;
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#ifdef CROW_ENABLE_DEBUG
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if (!ec && bytes_transferred != 4)
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{
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throw std::runtime_error("WebSocket:Mask:async_read fail:asio bug?");
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}
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#endif
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if (!ec)
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{
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state_ = WebSocketReadState::Payload;
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do_read();
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}
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else
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{
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close_connection_ = true;
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if (error_handler_)
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error_handler_(*this, ec.message());
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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check_destroy();
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}
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});
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}
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else
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{
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state_ = WebSocketReadState::Payload;
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do_read();
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}
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break;
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case WebSocketReadState::Payload:
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{
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auto to_read = static_cast<std::uint64_t>(buffer_.size());
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if (remaining_length_ < to_read)
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to_read = remaining_length_;
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adaptor_.socket().async_read_some(
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asio::buffer(buffer_, static_cast<std::size_t>(to_read)),
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[this](const asio::error_code& ec, std::size_t bytes_transferred) {
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is_reading = false;
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if (!ec)
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{
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fragment_.insert(fragment_.end(), buffer_.begin(), buffer_.begin() + bytes_transferred);
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remaining_length_ -= bytes_transferred;
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if (remaining_length_ == 0)
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{
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if (handle_fragment())
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{
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state_ = WebSocketReadState::MiniHeader;
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do_read();
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}
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}
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else
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do_read();
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}
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else
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{
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close_connection_ = true;
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if (error_handler_)
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error_handler_(*this, ec.message());
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adaptor_.shutdown_readwrite();
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adaptor_.close();
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check_destroy();
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}
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});
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}
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break;
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}
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}
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/// Check if the FIN bit is set.
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bool is_FIN()
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{
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return mini_header_ & 0x8000;
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}
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/// Extract the opcode from the header.
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int opcode()
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{
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return (mini_header_ & 0x0f00) >> 8;
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}
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/// Process the payload fragment.
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///
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/// Unmasks the fragment, checks the opcode, merges fragments into 1 message body, and calls the appropriate handler.
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bool handle_fragment()
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{
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if (has_mask_)
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{
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for (decltype(fragment_.length()) i = 0; i < fragment_.length(); i++)
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{
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fragment_[i] ^= ((char*)&mask_)[i % 4];
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}
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}
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switch (opcode())
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{
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case 0: // Continuation
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{
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message_ += fragment_;
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if (is_FIN())
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{
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if (message_handler_)
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message_handler_(*this, message_, is_binary_);
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message_.clear();
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}
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}
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break;
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case 1: // Text
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{
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is_binary_ = false;
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message_ += fragment_;
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if (is_FIN())
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{
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if (message_handler_)
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message_handler_(*this, message_, is_binary_);
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message_.clear();
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}
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}
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break;
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case 2: // Binary
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{
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is_binary_ = true;
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message_ += fragment_;
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if (is_FIN())
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{
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if (message_handler_)
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message_handler_(*this, message_, is_binary_);
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message_.clear();
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}
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}
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break;
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case 0x8: // Close
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{
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has_recv_close_ = true;
|
|
if (!has_sent_close_)
|
|
{
|
|
close(fragment_);
|
|
}
|
|
else
|
|
{
|
|
adaptor_.shutdown_readwrite();
|
|
adaptor_.close();
|
|
close_connection_ = true;
|
|
if (!is_close_handler_called_)
|
|
{
|
|
if (close_handler_)
|
|
close_handler_(*this, fragment_);
|
|
is_close_handler_called_ = true;
|
|
}
|
|
check_destroy();
|
|
return false;
|
|
}
|
|
}
|
|
break;
|
|
case 0x9: // Ping
|
|
{
|
|
send_pong(fragment_);
|
|
}
|
|
break;
|
|
case 0xA: // Pong
|
|
{
|
|
pong_received_ = true;
|
|
}
|
|
break;
|
|
}
|
|
|
|
fragment_.clear();
|
|
return true;
|
|
}
|
|
|
|
/// 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<asio::const_buffer> buffers;
|
|
buffers.reserve(sending_buffers_.size());
|
|
for (auto& s : sending_buffers_)
|
|
{
|
|
buffers.emplace_back(asio::buffer(s));
|
|
}
|
|
asio::async_write(
|
|
adaptor_.socket(), buffers,
|
|
[&](const asio::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");
|
|
handler_->remove_websocket(this);
|
|
if (sending_buffers_.empty() && !is_reading)
|
|
delete this;
|
|
}
|
|
|
|
|
|
struct SendMessageType
|
|
{
|
|
std::string payload;
|
|
Connection* self;
|
|
int opcode;
|
|
|
|
void operator()()
|
|
{
|
|
self->send_data_impl(this);
|
|
}
|
|
};
|
|
|
|
void send_data_impl(SendMessageType* s)
|
|
{
|
|
auto header = build_header(s->opcode, s->payload.size());
|
|
write_buffers_.emplace_back(std::move(header));
|
|
write_buffers_.emplace_back(std::move(s->payload));
|
|
do_write();
|
|
}
|
|
|
|
void send_data(int opcode, std::string&& msg)
|
|
{
|
|
SendMessageType event_arg{
|
|
std::move(msg),
|
|
this,
|
|
opcode};
|
|
|
|
post(std::move(event_arg));
|
|
}
|
|
|
|
private:
|
|
Adaptor adaptor_;
|
|
Handler* handler_;
|
|
|
|
std::vector<std::string> sending_buffers_;
|
|
std::vector<std::string> write_buffers_;
|
|
|
|
std::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};
|
|
uint64_t max_payload_bytes_{UINT64_MAX};
|
|
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&, const std::string&)> error_handler_;
|
|
std::function<bool(const crow::request&, void**)> accept_handler_;
|
|
};
|
|
} // namespace websocket
|
|
} // namespace crow
|