Fix monitoring mode

lib/individualCommands.js

@@ -33,6 +33,41 @@ RedisClient.prototype.select = RedisClient.prototype.SELECT = function select (d
     });
 };
 
+RedisClient.prototype.monitor = RedisClient.prototype.MONITOR = function (callback) {
+    // Use a individual command, as this is a special case that does not has to be checked for any other command
+    var self = this;
+    return this.send_command('monitor', [], function (err, res) {
+        if (err === null) {
+            self.reply_parser.returnReply = function (reply) {
+                // If in monitor mode, all normal commands are still working and we only want to emit the streamlined commands
+                // As this is not the average use case and monitor is expensive anyway, let's change the code here, to improve
+                // the average performance of all other commands in case of no monitor mode
+                if (self.monitoring) {
+                    var replyStr;
+                    if (self.buffers && Buffer.isBuffer(reply)) {
+                        replyStr = reply.toString();
+                    } else {
+                        replyStr = reply;
+                    }
+                    // While reconnecting the redis server does not recognize the client as in monitor mode anymore
+                    // Therefor the monitor command has to finish before it catches further commands
+                    if (typeof replyStr === 'string' && utils.monitor_regex.test(replyStr)) {
+                        var timestamp = replyStr.slice(0, replyStr.indexOf(' '));
+                        var args = replyStr.slice(replyStr.indexOf('"') + 1, -1).split('" "').map(function (elem) {
+                            return elem.replace(/\\"/g, '"');
+                        });
+                        self.emit('monitor', timestamp, args, replyStr);
+                        return;
+                    }
+                }
+                self.return_reply(reply);
+            };
+            self.monitoring = true;
+        }
+        utils.callback_or_emit(self, callback, err, res);
+    });
+};
+
 // Store info in this.server_info after each call
 RedisClient.prototype.info = RedisClient.prototype.INFO = function info (section, callback) {
     var self = this;

lib/utils.js

@@ -39,8 +39,6 @@ function print (err, reply) {
     }
 }
 
-var redisErrCode = /^([A-Z]+)\s+(.+)$/;
-
 // Deep clone arbitrary objects with arrays. Can't handle cyclic structures (results in a range error)
 // Any attribute with a non primitive value besides object and array will be passed by reference (e.g. Buffers, Maps, Functions)
 function clone (obj) {
@@ -102,7 +100,8 @@ module.exports = {
     reply_to_strings: replyToStrings,
     reply_to_object: replyToObject,
     print: print,
-    err_code: redisErrCode,
+    err_code: /^([A-Z]+)\s+(.+)$/,
+    monitor_regex: /^[0-9]{10,11}\.[0-9]+ \[[0-9]{1,3} [0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}:[0-9]{1,5}\].*/,
     clone: convenienceClone,
     callback_or_emit: callbackOrEmit,
     reply_in_order: replyInOrder