How to stop NodeJS/Express from caching mongodb query results - node.js

Question

It seems my Node JS or Express is caching the results from MongoDB, this seems to be an advantage for some, but for me it is causing a problem. I don't want the json response to be cached. Please suggest how to stop this.
This is my Server.js if you notice I have used res.headers and app.disable methods to prevent caching.
// set up ======================================================================
var express = require('express');
var path = require('path');
var logger = require('morgan');
var bodyParser = require('body-parser');
var app = express();
var server = require('http').Server(app);
var mongoose = require('mongoose'); // mongoose for mongodb
var port = process.env.PORT || 8000; // set the port
var database = require('./config/database'); // load the database config
var morgan = require('morgan');
var methodOverride = require('method-override');
var io = require('socket.io')(server);
var cors = require('cors');
var messageId = {};
// configuration ===============================================================
// Connect to DB
mongoose.connect(database.remoteUrl)
mongoose.Promise = global.Promise;
mongoose.connection.on('error', function(e) {
console.log('Can not connect Error:>>',e);
process.exit();
});
mongoose.connection.once('open', function(d) {
console.log("Successfully connected to the database");
})
//app.use(express.static('./public')); // set the static files location /public/img will be /img for users
app.use(morgan('dev')); // log every request to the console
app.use(bodyParser.urlencoded({'extended': 'true'})); // parse application/x-www-form-urlencoded
app.use(bodyParser.json()); // parse application/json
app.use(bodyParser.json({type: 'application/vnd.api+json'})); // parse application/vnd.api+json as json
app.use(methodOverride('X-HTTP-Method-Override')); // override with the X-HTTP-Method-Override header in the request
app.use(bodyParser.urlencoded({extended:true}))
app.use(bodyParser.json())
app.use(cors());
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header('Access-Control-Allow-Methods', 'DELETE, PUT');
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.header("Cache-Control", "no-cache, no-store, must-revalidate");
res.header("Pragma", "no-cache");
res.header("Expires", 0);
next();
});
app.disable('view cache');
io.set('origins', '*:*');
http = require('http'),
server = http.createServer(function (req, res) {
//res.writeHead(200,{'content-type':'text/plain'});
// res.write("Sever On");
// res.end();
}),
io = io.listen(server);
io.on('connection', function (socket) {
console.log('User Connected -- Server Online');
socket.on('message', function (msg,msgId) {
io.emit('message', "Hello");
console.log("message from client:", msg);
setInterval(function(){
io.emit("messageStatus",msgId);
},500)
});
});
app.use(require('./app/routes.js'));
app.listen(port);
//server.listen(port);
console.log("App listening on port " + port);
This is my Route.js
var express = require('express')
var app = module.exports = express.Router();
var UserProfile = require('./models/UserProfile');
app.get('/User', function (req, res) {
UserProfile.find({
EmailID: req.query.EmailID
}, function (err, profile) {
// if there is an error retrieving, send the error. nothing after res.send(err) will execute
if (err) {
return res.json({
"success": false,
"msg": err
})
console.log(err);
}
res.status(200).send(profile)
});
});
This is my provider.js
import { Injectable } from '#angular/core';
import { Http } from '#angular/http';
import 'rxjs/add/operator/map';
#Injectable()
export class ProfileProvider {
data : any
constructor(public http: Http,) {
}
// public getProfile(EmailID){
// console.log(this.http.get(CONFIG.apiUrl+'User?EmailID='+EmailID).map(response => response.json().result));
// return this.http.get(CONFIG.apiUrl+'User?EmailID='+EmailID).map(response => response.json().result);
// }
public getProfile(EmailID){
console.log("Provider,>>",EmailID)
if (this.data) {
return Promise.resolve(this.data); }
return new Promise(resolve => {
this.http.get('http://192.168.0.100:8000/User?EmailID='+EmailID)
.map(res => res.json())
.subscribe(data => {
this.data = data;
resolve(this.data);
});
});
}
}
Now if run this (http://192.168.0.100:8000/User?EmailID=abc#abc.com) on my browser and if I change the email ID, i get different responses. But in the ionic app it some how gives me the same responses even after changing the parameters
And I am using AWS and my MongoDB is hosted there.

Answer 1

Your problem is in the provider. You are caching the results of the api call in the data property.
if (this.data) {
return Promise.resolve(this.data); }
Try always fetching the data:
public getProfile(EmailID){
return new Promise(resolve => {
this.http.get('http://192.168.0.100:8000/User?EmailID='+EmailID)
.map(res => res.json())
.subscribe(data => {
resolve(data);
});
});
}