Node.js: making db variable available in controller files - javascript

I am fairly new to node.js.
I am currently using lowdb for my database while I get the app started.
In the index.js file I have:
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var request = require('request');
var path = require('path');
var low = require('lowdb');
var db = low('db.json');
var routes = require('./routes');
app.set('view engine', 'ejs');
app.set('views', path.join(__dirname, 'views'));
app.use(express.static(path.join(__dirname, '/public')));
app.use('/', routes);
server.listen(3000, function(){
console.log('listening on port 3000');
});
Then in my routes file I have something like:
var express = require('express');
var router = express.Router();
var account = require('./controllers/accounts.js');
router.post('/login', account.login);
router.get('/', function(req, res){
res.render('home');
});
module.exports = router;
And finally in my account controller I have:
exports.login = function(req, res){
var email = req.body.email;
var password = req.body.password;
...
}
The routing to controller system works. However I need to access the lowdb object from all of my routed controller functions (and also possibly elsewhere).
If in app.js I set:
global.db = db;
Then it seems to work, but from what I have read, setting this globally isn't the ideal solution. What is the appropriate way to be able to access the db from the controller files without having to set the db connection in every single file.

In your index.js file (application root) store the lowdb object in your express object :
var app = express();
var db = low('db.json');
app.db = db;
In your controller (accounts.js), access your database with req.app.db :
exports.login = function(req, res){
var email = req.body.email;
var password = req.body.password;
var db = req.app.db;
}

It looks like you can probably just setup and use the db directly in your routes file since you're not actually using the db in your main file. If it's that simple then I'd opt for doing that:
// routes file
var low = require('lowdb');
var db = low('db.json');
Alternatively, if you need to setup your db in the main file and pass it into the routes file and/or other modules, instead of exporting the router directly in the routes file, export a function which takes the db as input and returns the router. Then you can pass the db into the routes module when you require it.
// routes file
module.exports = function (db) {
// router setup using the input `db`
// ...
return router;
}
// index.js
var low = require('lowdb');
var db = low('db.json');
var routes = require('./routes')(db);

Related

Structure event listeners in Node.js [duplicate]

This question already has answers here:
How to separate routes on Node.js and Express 4?
(9 answers)
Closed 1 year ago.
In my NodeJS express application I have app.js that has a few common routes. Then in a wf.js file I would like to define a few more routes.
How can I get app.js to recognize other route handlers defined in wf.js file?
A simple require does not seem to work.
If you want to put the routes in a separate file, for example routes.js, you can create the routes.js file in this way:
module.exports = function(app){
app.get('/login', function(req, res){
res.render('login', {
title: 'Express Login'
});
});
//other routes..
}
And then you can require it from app.js passing the app object in this way:
require('./routes')(app);
Have a look at these examples: https://github.com/visionmedia/express/tree/master/examples/route-separation
In Express 4.x you can get an instance of the router object and import another file that contains more routes. You can even do this recursively so your routes import other routes allowing you to create easy-to-maintain URL paths.
For example, if I have a separate route file for my /tests endpoint already and want to add a new set of routes for /tests/automated I may want to break these /automated routes out into a another file to keep my /test file small and easy to manage. It also lets you logically group routes together by URL path which can be really convenient.
Contents of ./app.js:
var express = require('express'),
app = express();
var testRoutes = require('./routes/tests');
// Import my test routes into the path '/test'
app.use('/tests', testRoutes);
Contents of ./routes/tests.js:
var express = require('express'),
router = express.Router();
var automatedRoutes = require('./testRoutes/automated');
router
// Add a binding to handle '/tests'
.get('/', function(){
// render the /tests view
})
// Import my automated routes into the path '/tests/automated'
// This works because we're already within the '/tests' route
// so we're simply appending more routes to the '/tests' endpoint
.use('/automated', automatedRoutes);
module.exports = router;
Contents of ./routes/testRoutes/automated.js:
var express = require('express'),
router = express.Router();
router
// Add a binding for '/tests/automated/'
.get('/', function(){
// render the /tests/automated view
})
module.exports = router;
Building on #ShadowCloud 's example I was able to dynamically include all routes in a sub directory.
routes/index.js
var fs = require('fs');
module.exports = function(app){
fs.readdirSync(__dirname).forEach(function(file) {
if (file == "index.js") return;
var name = file.substr(0, file.indexOf('.'));
require('./' + name)(app);
});
}
Then placing route files in the routes directory like so:
routes/test1.js
module.exports = function(app){
app.get('/test1/', function(req, res){
//...
});
//other routes..
}
Repeating that for as many times as I needed and then finally in app.js placing
require('./routes')(app);
If you're using express-4.x with TypeScript and ES6, this would be the best template to use:
src/api/login.ts
import express, { Router, Request, Response } from "express";
const router: Router = express.Router();
// POST /user/signin
router.post('/signin', async (req: Request, res: Response) => {
try {
res.send('OK');
} catch (e) {
res.status(500).send(e.toString());
}
});
export default router;
src/app.ts
import express, { Request, Response } from "express";
import compression from "compression"; // compresses requests
import expressValidator from "express-validator";
import bodyParser from "body-parser";
import login from './api/login';
const app = express();
app.use(compression());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(expressValidator());
app.get('/public/hc', (req: Request, res: Response) => {
res.send('OK');
});
app.use('/user', login);
app.listen(8080, () => {
console.log("Press CTRL-C to stop\n");
});
Much cleaner than using var and module.exports.
Full recursive routing of all .js files inside /routes folder, put this in app.js.
// Initialize ALL routes including subfolders
var fs = require('fs');
var path = require('path');
function recursiveRoutes(folderName) {
fs.readdirSync(folderName).forEach(function(file) {
var fullName = path.join(folderName, file);
var stat = fs.lstatSync(fullName);
if (stat.isDirectory()) {
recursiveRoutes(fullName);
} else if (file.toLowerCase().indexOf('.js')) {
require('./' + fullName)(app);
console.log("require('" + fullName + "')");
}
});
}
recursiveRoutes('routes'); // Initialize it
in /routes you put whatevername.js and initialize your routes like this:
module.exports = function(app) {
app.get('/', function(req, res) {
res.render('index', { title: 'index' });
});
app.get('/contactus', function(req, res) {
res.render('contactus', { title: 'contactus' });
});
}
And build yet more on the previous answer, this version of routes/index.js will ignore any files not ending in .js (and itself)
var fs = require('fs');
module.exports = function(app) {
fs.readdirSync(__dirname).forEach(function(file) {
if (file === "index.js" || file.substr(file.lastIndexOf('.') + 1) !== 'js')
return;
var name = file.substr(0, file.indexOf('.'));
require('./' + name)(app);
});
}
I am trying to update this answer with "express": "^4.16.3". This answer is similar to the one from ShortRound1911.
server.js:
const express = require('express');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
const db = require('./src/config/db');
const routes = require('./src/routes');
const port = 3001;
const app = new express();
//...use body-parser
app.use(bodyParser.urlencoded({ extended: true }));
//...fire connection
mongoose.connect(db.url, (err, database) => {
if (err) return console.log(err);
//...fire the routes
app.use('/', routes);
app.listen(port, () => {
console.log('we are live on ' + port);
});
});
/src/routes/index.js:
const express = require('express');
const app = express();
const siswaRoute = require('./siswa_route');
app.get('/', (req, res) => {
res.json({item: 'Welcome ini separated page...'});
})
.use('/siswa', siswaRoute);
module.exports = app;
/src/routes/siswa_route.js:
const express = require('express');
const app = express();
app.get('/', (req, res) => {
res.json({item: 'Siswa page...'});
});
module.exports = app;
If you want a separate .js file to better organize your routes, just create a variable in the app.js file pointing to its location in the filesystem:
var wf = require(./routes/wf);
then,
app.get('/wf', wf.foo );
where .foo is some function declared in your wf.js file. e.g
// wf.js file
exports.foo = function(req,res){
console.log(` request object is ${req}, response object is ${res} `);
}
One tweak to all of these answers:
var routes = fs.readdirSync('routes')
.filter(function(v){
return (/.js$/).test(v);
});
Just use a regex to filter via testing each file in the array. It is not recursive, but it will filter out folders that don't end in .js
I know this is an old question, but I was trying to figure out something like for myself and this is the place I ended up on, so I wanted to put my solution to a similar problem in case someone else has the same issues I'm having. There's a nice node module out there called consign that does a lot of the file system stuff that is seen here for you (ie - no readdirSync stuff). For example:
I have a restful API application I'm trying to build and I want to put all of the requests that go to '/api/*' to be authenticated and I want to store all of my routes that go in api into their own directory (let's just call it 'api'). In the main part of the app:
app.use('/api', [authenticationMiddlewareFunction], require('./routes/api'));
Inside of the routes directory, I have a directory called "api" and a file called api.js. In api.js, I simply have:
var express = require('express');
var router = express.Router();
var consign = require('consign');
// get all routes inside the api directory and attach them to the api router
// all of these routes should be behind authorization
consign({cwd: 'routes'})
.include('api')
.into(router);
module.exports = router;
Everything worked as expected. Hope this helps someone.
index.js
const express = require("express");
const app = express();
const http = require('http');
const server = http.createServer(app).listen(3000);
const router = (global.router = (express.Router()));
app.use('/books', require('./routes/books'))
app.use('/users', require('./routes/users'))
app.use(router);
routes/users.js
const router = global.router
router.get('/', (req, res) => {
res.jsonp({name: 'John Smith'})
}
module.exports = router
routes/books.js
const router = global.router
router.get('/', (req, res) => {
res.jsonp({name: 'Dreams from My Father by Barack Obama'})
}
module.exports = router
if you have your server running local (http://localhost:3000) then
// Users
curl --request GET 'localhost:3000/users' => {name: 'John Smith'}
// Books
curl --request GET 'localhost:3000/books' => {name: 'Dreams from My Father by Barack Obama'}
I wrote a small plugin for doing this! got sick of writing the same code over and over.
https://www.npmjs.com/package/js-file-req
Hope it helps.
you can put all route functions in other files(modules) , and link it to the main server file.
in the main express file, add a function that will link the module to the server:
function link_routes(app, route_collection){
route_collection['get'].forEach(route => app.get(route.path, route.func));
route_collection['post'].forEach(route => app.post(route.path, route.func));
route_collection['delete'].forEach(route => app.delete(route.path, route.func));
route_collection['put'].forEach(route => app.put(route.path, route.func));
}
and call that function for each route model:
link_routes(app, require('./login.js'))
in the module files(for example - login.js file), define the functions as usual:
const login_screen = (req, res) => {
res.sendFile(`${__dirname}/pages/login.html`);
};
const forgot_password = (req, res) => {
console.log('we will reset the password here')
}
and export it with the request method as a key and the value is an array of objects, each with path and function keys.
module.exports = {
get: [{path:'/',func:login_screen}, {...} ],
post: [{path:'/login:forgotPassword', func:forgot_password}]
};

Express route not being recognized. Responds with 'Cannot GET'

app.js
var express = require("express");
var app = express();
var path = require('path');
var db = require('./db');
var bodyParser = require('body-parser');
app.listen(80);
app.set('view engine', 'jade');
app.set('views', "./views");
// app.get('/', _GetMainPage);
// app.get('/sites', _GetSites);
app.use(express.static(path.join(__dirname, 'public')));
app.use(bodyParser.urlencoded({ extended: true })); // Support encoded bodies
app.use(bodyParser.json()); // Support json encoded bodies
app.use(require('./controllers'));
./controllers/index.js
var express = require('express');
var router = express.Router();
router.use('/', require('./sites'));
router.use('/site', require('./site'));
module.exports = router;
./controllers/sites.js
var express = require('express');
var router = express.Router();
var site = require('../models/site');
router.get('/', function(req, res) {
site.getAll(function(err, rows){
if(err) {
res.send(err);
return;
}
res.render('sites', { sites : rows });
});
});
./controllers/site.js
var express = require('express');
var router = express.Router();
var site = require('../models/site');
router.get('/site', function(req, res) {
// console.log("get /site received. req.body: " + req.body);
res.render('site', {
site: {
name : req.params.name
}
});
});
module.exports = router;
When I request localhost/site I get a response saying:
Cannot GET /site
localhost/ works perfectly
I have been looking at this for a while and can't find the problem yet. If there is anything I can add, let me know. Thanks.
Thank you to the person that commented with the answer:
What happens if you navigate to /site/site? Your site.js route is relative to the route you provided in use. So it should be router.get('/' ... not router.get('/site' ...
The ./controllers/site route is already being routed to /site. On top of this I was calling router.get('/site', ...). This means it was actually routing to /site/site.
The solution is to just use router.get('/', ...) in the site.js file instead.
This really helped me, thank you.
Basically, the root path in the sub-app is defined in your core app where you mount it via the app.use() method.
the best example I can find from app.mountpath docs is here:
https://expressjs.com/en/4x/api.html#express.router
The app.mountpath property contains one or more path patterns on which a sub-app was mounted.
var express = require('express');
var app = express(); // the main app
var admin = express(); // the sub app
admin.get('/', function (req, res) {
console.log(admin.mountpath); // /admin
res.send('Admin Homepage');
});
app.use('/admin', admin); // mount the sub app
It is similar to the baseUrl property of the req object, except
req.baseUrl returns the matched URL path, instead of the matched
patterns.
If a sub-app is mounted on multiple path patterns, app.mountpath
returns the list of patterns it is mounted on, as shown in the
following example.
var admin = express();
admin.get('/', function (req, res) {
console.log(admin.mountpath); // [ '/adm*n', '/manager' ]
res.send('Admin Homepage');
});
var secret = express();
secret.get('/', function (req, res) {
console.log(secret.mountpath); // /secr*t
res.send('Admin Secret');
});
admin.use('/secr*t', secret); // load the 'secret' router on '/secr*t', on the 'admin' sub app
app.use(['/adm*n', '/manager'], admin); // load the 'admin' router on '/adm*n' and '/manager', on the parent app

How to implemet a session in Node/Express?

I am trying to understand how sessions work. I need to do a post to the route /task/save and do a get to /task/list where I am going to be getting the elements I posted in /task/save, the post should go with an object on req.body like this { "name" : "task name" }, and, before I post it, I need to modify that object and put an ID generated by node-uuid, then, I need to push those elements to an array and put them in a session with the name "task". I am using express-session and here is how I have my code so far
app.js
var express = require('express');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var uuid = require('node-uuid');
var session = require('express-session');
var _ = require('lodash');
var routes = require('./routes/index');
var save = require('./routes/save');
var app = express();
app.use(bodyParser.json());
app.use(cookieParser());
app.use(session({secret: '1234567890QWERTY'}));
app.use('/', routes);
app.use('/task/list', save);
app.use('/task/save', save);
});
module.exports = app;
here the folder routes where I have save.js
var express = require('express');
var router = express.Router();
/* GET task save */
router.get('/', function(req, res, next) {
res.send('Get the list of tasks');
});
router.post('/', function(req, res, next) {
res.send('Send body with name, taskName & the modified object including the UUID');
});
module.exports = router;
what are your recommendations in order for me to put those tasks in a session ?
Inside the router.post hander method, you need to add an array to the req.session variable if the array doesn't exist. It is within this array that you can save your tasks.
req.session.tasks = req.session.tasks || [] // set tasks to be a new array if it doesn't exist yet
req.session.tasks.push({"name":"I am a new task"})
Once you have a reference to the tasks array, you can store your task inside it.
In your handler for router.get, you'll have access to your tasks:
console.log(req.session.tasks) // [{"name":"I am a new task"}, .... ]

How to get app in router files (in Node/Express app)

My app.js looks like this:
app = express();
setup.configure(app);
//...more stuff (e.g. database setup, middleware definition, etc.)...
var api = require('./routes/api');
app.use('/api', api);
module.exports = app;
In the routes/api.js, I then have routes with middleware like this:
router.get('/myroute',
app.sessionMW,
function (req, res, next) {
//...
});
JSLint flags an error because I declare the app variable as global.
If I declare it with var, I get an error in the route because app is undefined. If I require the app in the routes file with var app = require('../app'), I get this error:
Error: Route.get() requires callback functions but got a [object
Undefined]
I would like to properly define the app by doing
var app = express();
But how do I access the app in the routes file?
According to the Express 4.x docs, you can access the app object easily through the request and response objects using req.app & res.app
The Express application object can be referred from the Request object
and the Response object as req.app, and res.app, respectively.
req.app
This property holds a reference to the instance of the Express application that is using the middleware.
res.app
res.app is identical to the req.app property in the Request object.
code-example:
server.js:
var path = require('path');
var express = require('express');
var app = express();
app.set('firends', 'nodejs, python');
var page = require(path.join(
__dirname,
'page'
));
app.use('', page);
app.listen(3000);
page.js:
var express = require('express');
var router = express.Router();
router.get('/test-route', function (req, res) {
var app = req.app; // get app object
res.send('firends are: ' + app.get('firends')); // get firends from app
});
module.exports = router;
Tips:
server.js and page.js are in the same folder.
run with command: node server.js
visit with url: http://127.0.0.1:3000/test-route
You can just pass your app object in your routes/api.js file:
app.js
var api = require('./routes/api')(app); // pass 'app'
routes/api.js
module.exports = function(app) {
...
router.get('/myroute', app.sessionMW, function (req, res, next) { //... });
...
})

Dynamic routes with different functions in express js

I have loads of router.get functions in my code which I think, could be reduced to a single switch-case function. Here is what I have tried:
function handlerA(req, res) {}
function handlerB(req, res) {}
var routes = {
'/url-one': handlerA,
'/url-two': handlerB
}
router.get('/*', function(req, res) {
var url = req.url;
if (routes[url]) {
routes[url](req, res);
}
});
This works but also, significantly slows my application. Is there any other solution which would not hit the performance of my app?
Thanks
Is there a reason you don't want to use router.get functions? I would guess express.js is internally performing the same logic that you are doing anyway. You are just replacing get functions with handlers.
If you are using similar logic between multiple routes, that may be worth abstracting.
I usually go with a setup like this:
app.js
routes.js
api/
user/
index.js
user.controller.js
user.model.js
image/
index.js
image.controller.js
image.model.js
/api/user/index.js:
var express = require('express');
var controller = require('./user.controller');
var router = express.Router();
router.get('/', controller.index);
router.post('/', controller.create);
module.exports = router;
/api/user/user.controller.js:
var User = require('./user.model');
exports.index = function(req, res) {
// Show list of users
};
exports.create = function (req, res, next) {
// Create user
};
/routes.js:
module.exports = function(app) {
// Insert routes below
app.use('/api/users', require('./api/user'));
app.use('/api/images', require('./api/image'));
// All undefined asset or api routes should return a 404
app.route('/:url(api|auth|components|app|bower_components|assets)/*')
.get(errors[404]);
// All other routes should redirect to the index.html
app.route('/*')
.get(function(req, res) {
res.sendfile(app.get('appPath') + '/index.html');
});
};
And lastly, the /app.js:
// Set default node environment to development
process.env.NODE_ENV = process.env.NODE_ENV || 'development';
var express = require('express');
var mongoose = require('mongoose');
var config = require('./config/environment');
// Connect to database
mongoose.connect(config.mongo.uri, config.mongo.options);
// Populate DB with sample data
if(config.seedDB) { require('./config/seed'); }
// Setup server
var app = express();
var server = require('http').createServer(app);
require('./config/express')(app);
require('./routes')(app);
// Start server
server.listen(config.port, config.ip, function () {
console.log('Express server listening on %d, in %s mode', config.port, app.get('env'));
});
// Expose app
exports = module.exports = app;
Most of this is directly from the Yeoman Generator Angular-Fullstack and it has a really nice setup!

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