Passing Redis Key-value in Routes in Node.js / Express - node.js

Question

This is similar to this question, but my code has multiple routes.
The code works below for what I want to do, but I want to know if there's a cleaner way to write it as I'm fairly new to Node/Express/Redis.
var express = require('express');
var router = express.Router();
var io = require('socket.io');
var redis = require('./../lib/redis');
redis.get('count', function(err, value) {
if(err) throw err;
/* GET Dashboard */
router.get('/', function(req, res) {
res.render('dashboard', {title: 'Data Dashboard', count: value });
});
/* GET Backend */
router.get('/backend', function(req, res) {
res.render('backend', {title: 'Backend', count: value });
});
});
module.exports = router;
Basically, I'm just passing a single Redis key-value to both of my routes.
Any suggestions to clean it up are appreciated.

Answer 1

The way your code is written you'll be passing the same value of the count key for your whole application life-cycle. There's nothing wrong with the code from a cleaning up perspective, but from a service point of view, the routes shouldn't be within the REDIS GET callback.
Getting the value within the route
// Use everytime you need to count the key
function redisCount = function(callback) {
redis.get('count', function(err, value) {
if(err) callback(err)
callback(null, value)
}
}
/* GET Dashboard */
router.get('/', function(req, res) {
redisCount(function(err,value) {
if(err) throw err;
res.render('dashboard', {title: 'Data Dashboard', count: value });
})
});
/* GET Backend */
router.get('/backend', function(req, res) {
redisCount(function(err,value) {
if(err) throw err;
res.render('backend', {title: 'Backend', count: value });
})
});
However if you do this count call for absolutely every single route, I would suggest a piece of middleware that just sets value into the context for every call:
Getting the value in a separate middleware
app.use(function (req, res, next) {
// using the same function for the redis count
redisCount(function(err, value) {
// respond with error
if (err) res.status("Could not connect to Redis")
// otherwise set the value in the session
req.session.value = value
// and move on to the next middleware
next()
});
});
// now simply declare your routes
/* GET Dashboard */
router.get('/', function(req, res) {
res.render('dashboard', {title: 'Data Dashboard', count: req.session.value });
});
/* GET Backend */
router.get('/backend', function(req, res) {
res.render('backend', {title: 'Backend', count: req.session.value });
});