Nodejs redis Q promises, how to make it work?

Question

I am trying to get multiple values ​​from redis, combine them and eventually send. But I just can't get these promises to work.

These are simple get functions from redis

 client.get('user:1:id',function(err,data){ // here I have data which contains user ID }); client.get('user:1:username',function(err,data){ // here I have data which contains username }); 

Now I want to get the ID and username and send them, but I don't know how to do this. I manage to get it to work with callbacks, but this is a very dirty result, so I tried to wrap anonymous functions in Q.fcall even after the .then call, which looks something like this.

 client.get('user:1:id',Q.fcall(function(err,data){ return data; }).then(function(val) { // do something })); 

but it gives me an error because too many arguments have been passed, and I'm not even sure if this will help me, even if it works.

Answer 1

 Q.all([Q.ninvoke(client, 'get', 'user:1:id'), Q.ninvoke(client, 'get', 'user:1:username')]).then(function (data) { var id = data[0]; var username = data[1]; // do something with them }); 

See https://github.com/kriskowal/q#adapting-node

Answer 2

I use the simple RequireJS module, using node -redis and whenjs to create a raised redis wrapper:

 define [ 'redis/lib/commands' 'when' 'when/node/function' ], (Commands, When, NodeFn) -> 'use strict' lift = (redis) -> wrapped = {} Commands.map (cmd) -> wrapped[cmd] = (args...) -> def = When.defer() args.push NodeFn.createCallback def.resolver redis[cmd].apply redis, args def.promise wrapped {lift} 

The use is simple:

 client = lift redis.createClient() client.get("hello").then console.log, console.error 

Answer 3

Using Promise, Bluebird and node_redis:

 import { RedisClient, createClient, ClientOpts } from "redis"; import { promisifyAll, PromisifyAllOptions } from "bluebird"; export module FMC_Redis { export class Redis { opt: ClientOpts; private rc: RedisClient; private rcPromise: any; private static _instance: Redis = null; public static current(_opt?: ClientOpts): Redis { if (!Redis._instance) { Redis._instance = new Redis(_opt); Redis._instance.redisConnect(); } return Redis._instance; } public get client(): RedisClient { if (!this.rc.connected) throw new Error("There is no connection to Redis DB!"); return this.rc; } /******* BLUEBIRD ********/ public get clientAsync(): any { // promisifyAll functions of redisClient // creating new redis client object which contains xxxAsync(..) functions. return this.rcPromise = promisifyAll(this.client); } private constructor(_opt?: ClientOpts) { if (Redis._instance) return; this.opt = _opt ? _opt : { host: "127.0.0.1", port: 6379, db: "0" }; } public redisConnect(): void { this.rc = createClient(this.opt); this.rc .on("ready", this.onReady) .on("end", this.onEnd) .on("error", this.onError); } private onReady(): void { console.log("Redis connection was successfully established." + arguments); } private onEnd(): void { console.warn("Redis connection was closed."); } private onError(err: any): void { console.error("There is an error: " + err); } /****** PROMISE *********/ // promise redis test public getRegularPromise() { let rc = this.client; return new Promise(function (res, rej) { console.warn("> getKeyPromise() ::"); rc.get("cem", function (err, val) { console.log("DB Response OK."); // if DB generated error: if (err) rej(err); // DB generated result: else res(val); }); }); } /******* ASYNC - AWAIT *******/ // async - await test function public delay(ms) { return new Promise<string>((fnResolve, fnReject) => { setTimeout(fnResolve("> delay(" + ms + ") > successfull result"), ms); }); } public async delayTest() { console.log("\n****** delayTest ") let a = this.delay(500).then(a => console.log("\t" + a)); let b = await this.delay(400); console.log("\tb::: " + b); } // async - await function public async getKey(key: string) { let reply = await this.clientAsync.getAsync("cem"); return reply.toString(); } } } let a = FMC_Redis.Redis.current(); // setTimeout(function () { // console.warn(a.client.set("cem", "naber")); // console.warn(a.client.get("cem")); // console.warn(a.client.keys("cem")); // }, 1000); /***** async await test client *****/ a.delayTest(); /** Standart Redis Client test client */ setTimeout(function () { a.client.get("cem", function (err, val) { console.log("\n****** Standart Redis Client") if (err) console.error("\tError: " + err); else console.log("\tValue ::" + val); }); }, 100) /***** Using regular Promise with Redis Client > test client *****/ setTimeout(function () { a.getRegularPromise().then(function (v) { console.log("\n***** Regular Promise with Redis Client") console.log("\t> Then ::" + v); }).catch(function (e) { console.error("\t> Catch ::" + e); }); }, 100); /***** Using bluebird promisify with Redis Client > test client *****/ setTimeout(function () { var header = "\n***** bluebird promisify with Redis Client"; a.clientAsync.getAsync("cem").then(result => console.log(header + result)).catch(console.error); }, 100);