Add simple Redis Server which is only capable of doing publish / subscribe. New ws redis_server sub-command to use it. The server is used in the unittest, so that we can run on CI in environment where redis isn not available like github actions env.

ixsnake/ixsnake/IXRedisServer.cpp

@@ -0,0 +1,300 @@
+/*
+ *  IXRedisServer.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone, Inc. All rights reserved.
+ */
+
+#include "IXRedisServer.h"
+
+#include <ixwebsocket/IXNetSystem.h>
+#include <ixwebsocket/IXSocketConnect.h>
+#include <ixwebsocket/IXSocketFactory.h>
+#include <ixwebsocket/IXSocket.h>
+#include <ixwebsocket/IXCancellationRequest.h>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+namespace ix
+{
+    RedisServer::RedisServer(int port, const std::string& host, int backlog, size_t maxConnections)
+        : SocketServer(port, host, backlog, maxConnections)
+        , _connectedClientsCount(0)
+        , _stopHandlingConnections(false)
+    {
+        ;
+    }
+
+    RedisServer::~RedisServer()
+    {
+        stop();
+    }
+
+    void RedisServer::stop()
+    {
+        stopAcceptingConnections();
+
+        _stopHandlingConnections = true;
+        while (_connectedClientsCount != 0)
+        {
+            std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        }
+        _stopHandlingConnections = false;
+        
+        SocketServer::stop();
+    }
+
+    void RedisServer::handleConnection(int fd, std::shared_ptr<ConnectionState> connectionState)
+    {
+        _connectedClientsCount++;
+
+        std::string errorMsg;
+        auto socket = createSocket(fd, errorMsg);
+
+        // Set the socket to non blocking mode + other tweaks
+        SocketConnect::configure(fd);
+
+        while (!_stopHandlingConnections)
+        {
+            std::vector<std::string> tokens;
+            if (!parseRequest(socket, tokens))
+            {
+                if (_stopHandlingConnections)
+                {
+                    logError("Cancellation requested");
+                }
+                else
+                {
+                    logError("Error parsing request");
+                }
+                break;
+            }
+
+            bool success = false;
+
+            // publish
+            if (tokens[0] == "COMMAND")
+            {
+                success = handleCommand(socket, tokens);
+            }
+            else if (tokens[0] == "PUBLISH")
+            {
+                success = handlePublish(socket, tokens);
+            }
+            else if (tokens[0] == "SUBSCRIBE")
+            {
+                success = handleSubscribe(socket, tokens);
+            }
+
+            if (!success)
+            {
+                if (_stopHandlingConnections)
+                {
+                    logError("Cancellation requested");
+                }
+                else
+                {
+                    logError("Error processing request for command: " + tokens[0]);
+                }
+                break;
+            }
+        }
+
+        cleanupSubscribers(socket);
+
+        logInfo("Connection closed for connection id " + connectionState->getId());
+        connectionState->setTerminated();
+        Socket::closeSocket(fd);
+
+        _connectedClientsCount--;
+    }
+
+    void RedisServer::cleanupSubscribers(std::shared_ptr<Socket> socket)
+    {
+        std::lock_guard<std::mutex> lock(_mutex);
+
+        for (auto&& it : _subscribers)
+        {
+            it.second.erase(socket);
+        }
+
+        for (auto it : _subscribers)
+        {
+            std::stringstream ss;
+            ss << "Subscription id: " << it.first
+               << " #subscribers: " << it.second.size();
+
+            logInfo(ss.str());
+        }
+    }
+
+    size_t RedisServer::getConnectedClientsCount()
+    {
+        return _connectedClientsCount;
+    }
+
+    bool RedisServer::startsWith(const std::string& str,
+                                 const std::string& start)
+    {
+        return str.compare(0, start.length(), start) == 0;
+    }
+
+    std::string RedisServer::writeString(const std::string& str)
+    {
+        std::stringstream ss;
+        ss << "$";
+        ss << str.size();
+        ss << "\r\n";
+        ss << str;
+        ss << "\r\n";
+
+        return ss.str();
+    }
+
+    bool RedisServer::parseRequest(
+        std::shared_ptr<Socket> socket,
+        std::vector<std::string>& tokens)
+    {
+        // Parse first line
+        auto cb = makeCancellationRequestWithTimeout(30, _stopHandlingConnections);
+        auto lineResult = socket->readLine(cb);
+        auto lineValid = lineResult.first;
+        auto line = lineResult.second;
+
+        if (!lineValid) return false;
+
+        std::string str = line.substr(1);
+        std::stringstream ss;
+        ss << str;
+        int count;
+        ss >> count;
+
+        for (int i = 0; i < count; ++i)
+        {
+            auto lineResult = socket->readLine(cb);
+            auto lineValid = lineResult.first;
+            auto line = lineResult.second;
+
+            if (!lineValid) return false;
+
+            int stringSize;
+            std::stringstream ss;
+            ss << line.substr(1, line.size() - 1);
+            ss >> stringSize;
+
+            auto readResult = socket->readBytes(stringSize, nullptr, nullptr);
+
+            if (!readResult.first) return false;
+
+            // read last 2 bytes (\r\n)
+            char c;
+            socket->readByte(&c, nullptr);
+            socket->readByte(&c, nullptr);
+
+            tokens.push_back(readResult.second);
+        }
+
+        return true;
+    }
+
+    bool RedisServer::handleCommand(
+        std::shared_ptr<Socket> socket,
+        const std::vector<std::string>& tokens)
+    {
+        if (tokens.size() != 1) return false;
+
+        auto cb = makeCancellationRequestWithTimeout(30, _stopHandlingConnections);
+        std::stringstream ss;
+
+        // return 2 nested arrays
+        ss << "*2\r\n";
+
+        //
+        // publish
+        //
+        ss << "*6\r\n";
+        ss << writeString("publish"); // 1
+        ss << ":3\r\n"; // 2
+        ss << "*0\r\n"; // 3
+        ss << ":1\r\n"; // 4
+        ss << ":2\r\n"; // 5
+        ss << ":1\r\n"; // 6
+
+        //
+        // subscribe
+        //
+        ss << "*6\r\n";
+        ss << writeString("subscribe"); // 1
+        ss << ":2\r\n"; // 2
+        ss << "*0\r\n"; // 3
+        ss << ":1\r\n"; // 4
+        ss << ":1\r\n"; // 5
+        ss << ":1\r\n"; // 6
+
+        socket->writeBytes(ss.str(), cb);
+
+        return true;
+    }
+
+    bool RedisServer::handleSubscribe(
+        std::shared_ptr<Socket> socket,
+        const std::vector<std::string>& tokens)
+    {
+        if (tokens.size() != 2) return false;
+
+        auto cb = makeCancellationRequestWithTimeout(30, _stopHandlingConnections);
+        std::string channel = tokens[1];
+
+        // Respond
+        socket->writeBytes("*3\r\n", cb);
+        socket->writeBytes(writeString("subscribe"), cb);
+        socket->writeBytes(writeString(channel), cb);
+        socket->writeBytes(":1\r\n", cb);
+
+        std::lock_guard<std::mutex> lock(_mutex);
+        _subscribers[channel].insert(socket);
+
+        return true;
+    }
+
+    bool RedisServer::handlePublish(
+        std::shared_ptr<Socket> socket,
+        const std::vector<std::string>& tokens)
+    {
+        if (tokens.size() != 3) return false;
+
+        auto cb = makeCancellationRequestWithTimeout(30, _stopHandlingConnections);
+        std::string channel = tokens[1];
+        std::string data = tokens[2];
+
+        // now dispatch the message to subscribers (write custom method)
+        std::lock_guard<std::mutex> lock(_mutex);
+        auto it = _subscribers.find(channel);
+        if (it == _subscribers.end()) 
+        {
+            // return the number of clients that received the message, 0 in that case
+            socket->writeBytes(":0\r\n", cb);
+            return true;
+        }
+
+        auto subscribers = it->second;
+        for (auto jt : subscribers)
+        {
+            jt->writeBytes("*3\r\n", cb);
+            jt->writeBytes(writeString("message"), cb);
+            jt->writeBytes(writeString(channel), cb);
+            jt->writeBytes(writeString(data), cb);
+        }
+
+        // return the number of clients that received the message.
+        std::stringstream ss;
+        ss << ":"
+           << std::to_string(subscribers.size())
+           << "\r\n";
+        socket->writeBytes(ss.str(), cb);
+
+        return true;
+    }
+
+} // namespace ix