Wrap redis client using kriskowal/q promise

redis-q.js

/**
 * Wrap redis client using kriskowal/q promise
 */
var redis = require('redis');
var redisClient = redis.createClient();
var Multi = redis.Multi;
var Q = require('q');
var _ = require('underscore');

var object = function(o) {
  function F(){}
  F.prototype = o;
  return new F();
};

var miscellaneous = function(subType, superType) {
  var prototype = object(superType.prototype);
  prototype.constructor = subType;
  subType.prototype = prototype;
};


var commands = require('redis/lib/commands');

function RedisQ() {
  //do nothing
}

RedisQ.prototype.sendCommand = function(command, args, callback) {
  var deferred = Q.defer();
  redisClient.send_command.call(redisClient, command, args, function(err, replies) {
    if(err) {
      deferred.reject(err);
    } else {
      deferred.resolve(replies);
    }
  });
  return deferred.promise.nodeify(callback);
};

_.each(commands, function(command) {
  RedisQ.prototype[command] = function(args, callback) {

    if(_.isArray(args) && _.isFunction(callback)) {
      return this.sendCommand(command, args, callback);
    } else if(_.isArray(args))
      return this.sendCommand(command, args);
    } else {
      // arguments is separate arguments
      if(!_.isFunction(arguments[arguments.length - 1])){
        return this.sendCommand(command, _.toArray(arguments));
      } else {

        var argumentsArray = _.toArray(arguments);
        var lastArg = argumentsArray.pop();
        return this.sendCommand(command, argumentsArray, lastArg);
      }
    }
  };
});

exports.client = function() {
  return new RedisQ();
};

function MultiQ(args) {
  Multi.call(this, redisClient, args);
}

miscellaneous.inheritPrototype(MultiQ, Multi);

var superExec = MultiQ.prototype.exec;

MultiQ.prototype.exec = function(callback) {
  var deferred = Q.defer();
  superExec.call(this, function(err, replies){
    if(err) {
      deferred.reject(err);
    } else {
      deferred.resolve(replies);
    }
  });
  return deferred.promise.nodeify(callback);
};

RedisQ.prototype.multi = function(args) {
  return new MultiQ(redisClient, args);
};