Feature/redis (#23)

* Fix warning

* (cmake) add a warning about 32/64 conversion problems.

* simple redis clients

* can publish to redis

* redis subscribe

* display messages received per second

* verbose flag

* (cmake) use clang only compile option -Wshorten-64-to-32 when compiling with clang

ws/ws_redis_subscribe.cpp

@@ -0,0 +1,66 @@
+/*
+ *  ws_redis_subscribe.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone, Inc. All rights reserved.
+ */
+
+#include <iostream>
+#include <sstream>
+#include <chrono>
+#include "IXRedisClient.h"
+
+namespace ix
+{
+    int ws_redis_subscribe_main(const std::string& hostname,
+                                int port,
+                                const std::string& channel,
+                                bool verbose)
+    {
+        RedisClient redisClient;
+        if (!redisClient.connect(hostname, port))
+        {
+            std::cerr << "Cannot connect to redis host" << std::endl;
+            return 1;
+        }
+
+        std::chrono::time_point<std::chrono::steady_clock> lastTimePoint;
+        int msgPerSeconds = 0;
+        int msgCount = 0;
+
+        auto callback = [&lastTimePoint, &msgPerSeconds, &msgCount, verbose]
+                         (const std::string& message)
+        {
+            if (verbose)
+            {
+                std::cout << message << std::endl;
+            }
+
+            msgPerSeconds++;
+
+            auto now = std::chrono::steady_clock::now();
+            if (now - lastTimePoint > std::chrono::seconds(1))
+            {
+                lastTimePoint = std::chrono::steady_clock::now();
+
+                msgCount += msgPerSeconds;
+
+                // #messages 901 msg/s 150
+                std::cout << "#messages " << msgCount << " "
+                          << "msg/s " << msgPerSeconds
+                          << std::endl;
+
+                msgPerSeconds = 0;
+            }
+        };
+
+        std::cerr << "Subscribing to " << channel << "..." << std::endl;
+        if (!redisClient.subscribe(channel, callback))
+        {
+            std::cerr << "Error subscribing to channel " << channel << std::endl;
+            return 1;
+        }
+
+        return 0;
+    }
+}
+