From 90bd600c5025ede4db99122f13dfb07b27de46ae Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Sat, 30 Nov 2019 01:38:08 +0300
Subject: initial commit

---
 client/transport.hpp | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 client/transport.hpp

(limited to 'client/transport.hpp')

diff --git a/client/transport.hpp b/client/transport.hpp
new file mode 100644
index 0000000..ae56f73
--- /dev/null
+++ b/client/transport.hpp
@@ -0,0 +1,104 @@
+#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}
+    { }
+};
+
+}
+
+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, '\n');
+        const auto data = boost::asio::buffer_cast<const char*>(m_buffer.data());
+        const std::string result{data, bytes - 1};
+        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);
+}
+
+}
-- 
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