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// Copyright (c) 2019 Egor Tensin <Egor.Tensin@gmail.com>
// This file is part of the "math-server" project.
// For details, see https://github.com/egor-tensin/math-server.
// Distributed under the MIT License.
#pragma once
#include "error.hpp"
#include <boost/asio.hpp>
#include <boost/system/system_error.hpp>
#include <functional>
#include <memory>
#include <string>
namespace math::client {
namespace transport {
class Error : public client::Error {
public:
explicit Error(const std::string& msg) : client::Error{"transport error: " + msg} {}
};
} // namespace transport
class Transport {
public:
virtual ~Transport() = default;
using ProcessResult = std::function<void(const std::string&)>;
virtual void send_query(const std::string&, const ProcessResult&) = 0;
};
using TransportPtr = std::unique_ptr<Transport>;
class NetworkTransport : public Transport {
public:
static constexpr auto DEFAULT_PORT = "18000";
NetworkTransport(const std::string& host, const std::string& port)
: m_host{host}, m_port{port} {}
protected:
const std::string m_host;
const std::string m_port;
};
class BlockingNetworkTransport : public NetworkTransport {
public:
BlockingNetworkTransport(const std::string& host, const std::string& port)
: NetworkTransport{host, port}, m_socket{m_io_context} {
try {
connect();
} catch (const boost::system::system_error& e) {
throw transport::Error{e.what()};
}
}
void send_query(const std::string& query, const ProcessResult& on_reply) override {
std::string reply;
try {
reply = send_query(query);
} catch (const boost::system::system_error& e) {
throw transport::Error{e.what()};
}
on_reply(reply);
}
private:
void connect() {
boost::asio::ip::tcp::resolver resolver{m_io_context};
boost::asio::connect(m_socket, resolver.resolve(m_host, m_port));
}
std::string send_query(const std::string& query) {
write(query);
return read_line();
}
void write(std::string input) {
input += '\n';
boost::asio::write(m_socket, boost::asio::const_buffer{input.c_str(), input.size()});
}
std::string read_line() {
const auto bytes = boost::asio::read_until(m_socket, m_buffer, "\r\n");
const auto data = boost::asio::buffer_cast<const char*>(m_buffer.data());
const std::string result{data, bytes - 2}; // Skip \r\n
m_buffer.consume(bytes);
return result;
}
boost::asio::io_context m_io_context;
boost::asio::ip::tcp::socket m_socket;
boost::asio::streambuf m_buffer;
};
inline TransportPtr make_blocking_network_transport(const std::string& host,
const std::string& port) {
return std::make_unique<BlockingNetworkTransport>(host, port);
}
} // namespace math::client
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