Express, node.js and redis: Separated function to access data

Question

Express, node.js and redis: Separated function to access data

Im trying to create a file 'users.js' where id like to manage all the redis accesses to the users data. In this file i have the next function, where i get the users ive saved in a list, to then load all of them from their keys:

exports.getUsers = function(){
    var usrs;
    client.lrange('users', 0, -1, function(err, rep){
        client.mget(rep, function(e,r){
            usrs = r;
        });
    });
    return usrs;
};

I have another file 'admin.js' where i try to manage the routes for my administration panel. In this file I require the users.js file, and i call to the users.getUsers() function. I expect to get an array with the users objects, or at least the string with all of them. The problem is that it always returns 'undefined'.

As i understand it, what is happening is that i try to return the usrs variable before the mget finish with the callback. But i dont know how to solve that.

The question is... how can i make the return statement wait for mget? Is there any other way to organize the code and keep the DB accesses separated by fields?

node.js
express
redis

Answer 1

You can't make getUsers wait for the response before returning, so you need to have your function support a callback parameter that your function calls when the data is ready:

exports.getUsers = function(callback){
    client.lrange('users', 0, -1, function(err, rep){
        client.mget(rep, function(e,usrs){
            callback(e,usrs);
        });
    });
};