How to use express route param to access database object - javascript

I'm trying to route different radio sessions/episodes from database queries with express.js. I'm able to grab the route param from the URL in my express route. But I'm unsure how to use the param to query the database for the right object.
I'm able to get this to work by hardcoding the param into my service as shown below with the 'title' variable in service.js. Currently, I only know how to pass variables from express to the view. Is there a way to pass the title param from my express route to the service.js file?
Routes.js
'use strict';
const express = require('express');
const Sessions = require('../models/sessions')
const routes = express.Router();
const apiRoutes = express.Router();
apiRoutes.get('/sessions', (req, res) => {
Sessions.find({}, (err, sessions) => {
if(err) {
return res.status(500).json({message: err.message});
}
res.json({sessions: sessions});
})
});
routes.get('/', (req, res, next) => {
return res.render('index', {title: 'Home'});
});
// I added this bit of code after realizing I needed to use mongoose to query the database. I'm still unsure how to pass the object to my javascript but I'm getting closer.
routes.get('/:title', function (req, res, next) {
const title = req.params.title
Sessions.find((err, sessions) => {
if (err) return console.error(err);
for (let i = 0; i < sessions.length; i++) {
if (title === sessions[i].title.toLowerCase()) {
res.render('session')
}
}
})
})
module.exports = [routes, apiRoutes];
index.js
'use strict';
const express = require('express');
const app = express();
const [routes, apiRoutes] = require('./src/routes');
require('./src/database');
require('./src/seed');
app.use('/', express.static('public'));
app.set('view engine', 'pug');
app.set('views', __dirname + '/views');
app.use('/api', apiRoutes);
app.use('/', routes);
app.listen(process.env.PORT || 8082);
service.js
const root = window.location.origin;
const title = 'session 1'
function callService(){
service(`${root}/api/sessions`)
.then(retrieveSession)
.catch(function(e) {
console.log(e)
});
}
function retrieveSession(data) {
for (let i = 0; i < data.sessions.length; i++) {
if(data.sessions[i].title.toLowerCase() === title) {
return data.sessions[i];
}
}
}
function service(url) {
return new Promise(function(res, rej) {
var httpRequest = new XMLHttpRequest();
httpRequest.open('GET', url);
httpRequest.onreadystatechange = handleResponse;
httpRequest.onerror = function(error) {
rej(error)
}
httpRequest.send();
function handleResponse() {
if (httpRequest.readyState === 4) {
if (httpRequest.status === 200) {
var data = JSON.parse(httpRequest.responseText);
res(data)
} else {
rej(this.statusText)
}
}
};
});
}

I was able to achieve the desired result by passing the data to the view via mongoose with the following snippet.
routes.get('/:title', function (req, res, next) { // Passes url param
const title = req.params.title //stores url param in varaible
Sessions.findOne({ 'title': title }, function (err, session) { // compares url param against my mongoose schema and queries the database for the desired object
if (err) return handleError(err); // checks for errors
res.render('session', {session: session}); // renders the page while passing the desired data.
})
})

Related

Express, using same routes with different imports?

I'm trying to make the a multi-language website. I've decided to go with data objects, to fill in all the text necessary. The routes I'm using for the 2 languages are exactly the same with only a difference in the import. Is there any way to make this happen without code duplication?
The templating engine is Express Handlebars, so if there is another solution for making a website multi-language, I'm open to implementing it :)
Thanks in advance for taking the time to read this.
The code in my routes for Sl language:
const express = require("express"),
router = express.Router(),
data = require("../Views/res/lang/sl");
router.get("/", (req, res) => {
data.Home = setupDataObject(data.Home, req.originalUrl, "Home");
res.render("homepage", data.Home);
});
router.get("/About", (req, res) => {
data.About = setupDataObject(data.About, req.originalUrl, "About");
res.render("About", data.About);
});
function setupDataObject(data, url, active) {
data.current = url.substring(4);
data.active = { [active]: true };
return data;
}
module.exports = router;
And the English version
const express = require("express"),
router = express.Router(),
data = require("../Views/res/lang/en");
router.get("/", (req, res) => {
data.Home = setupDataObject(data.Home, req.originalUrl, "Home");
res.render("homepage", data.Home);
});
router.get("/About", (req, res) => {
data.About = setupDataObject(data.About, req.originalUrl, "About");
res.render("About", data.About);
});
function setupDataObject(data, url, active) {
data.current = url.substring(4);
data.active = { [active]: true };
return data;
}
module.exports = router;
You can handle the locale in using with the url params, no ?
const express = require("express"),
router = express.Router();
router.get("/:locale/", (req, res) => {
const data = require("../Views/res/lang/" + locale);
data.Home = setupDataObject(data.Home, req.originalUrl, "Home");
res.render("homepage", data.Home);
});
router.get("/:locale/About", (req, res) => {
const data = require("../Views/res/lang/" + locale);
data.About = setupDataObject(data.About, req.originalUrl, "About");
res.render("About", data.About);
});
function setupDataObject(data, url, active) {
data.current = url.substring(4);
data.active = { [active]: true };
return data;
}
module.exports = router;

Request is not finished yet error with mongoDB and Express

I get a message Request is not finished yet and no data will be sent, if I do patch and delete requests in my app ( the post and get request work well)
Here are my requests
In service (front, Angular 4) I create the requests
api = 'http://localhost:3000/tasks';
deleteData(id) {
return this.http.delete( this.api, id);
}
patch(data) {
return this.http.patch( this.api, data);
}
And then call them in component
this.deleteData(this.checkedItems);
this.service.patch(result.data).subscribe(d => {
this.tasks = d;
});
The service
The PATCH request get req.body via console.log - so it should works, but it doesn't
The DELETE request doesn't get any data! The req.body is empty! But I need to pass the array of ids, so I can't do it via params.
Could you please help me or give a hint? Here is my service
const express = require('express');
const path = require('path');
const http = require('http');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');
const cors = require('cors');
var Schema = mongoose.Schema;
const app = express();
//Middleware for CORS
app.use(cors());
app.use(express.json());
// Parsers for POST data
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
// Point static path to dist
app.use(express.static(path.join(__dirname, 'dist')));
var todoSchema = new Schema({
taskName: String,
createdAt: Date,
isDone: Boolean,
prioraty: String
}, {
collection: 'tasks'
});
var Model = mongoose.model('Model', todoSchema);
//replace when DB is online
mongoose.connect('mongodb://localhost:27017/admin').then(() => {
console.log("connected");
}).catch (() => {
console.log("not connected");
});
mongoose.connection.once('open', function () {
console.log('mongodb connected.');
});
app.patch('/tasks', function (req, res) {
console.log(req.body);
var updateObject = {
'taskName': req.body.taskName,
'isDone': req.body.isDone,
'prioraty': req.body.prioraty
}
var id = req.body._id;
Model.collection.update({_id : id}, {$set: updateObject});
});
app.delete('/tasks', function(req,res){
console.log('Delete', req.body);
var ids = [];
for (let i = 0; i < req.body.length; i ++) {
ids.push(req.body[i]._id);
}
var myquery = { _id: { $in: ids } };
Model.collection.deleteMany(myquery, function(err, obj) {
if (err) throw err;
});
});
const port = process.env.PORT || '3000';
app.set('port', port);
/**
* Create HTTP server.
*/
const server = http.createServer(app);
/**
* Listen on provided port, on all network interfaces.
*/
server.listen(port, () => console.log(`API running on localhost:${port}`));
You need to close the connection when you're done handling the request, otherwise the client will wait for the server to send a response until the request timeout is reached.
app.patch('/tasks', function (req, res) {
...
Model.collection.update({_id : id}, {$set: updateObject}, function (err) {
if (err) {
console.error(err);
return res.sendStatus(500);
}
res.sendStatus(200);
});
});
app.delete('/tasks', function(req,res){
...
Model.collection.deleteMany(myquery, function(err) {
if (err) {
console.error(err);
return res.sendStatus(500);
}
res.sendStatus(200);
});
});
As for the DELETE request not having a req.body, that's because Angular 4's http client doesn't allow a body for DELETE requests. Its API for DELETE requests looks like this: this.http.delete(url, httpOptions), with no body support. You'll have to use query parameters if you need to send an array of ids. Query params does support arrays, they look something like this: https://myurl.xyz/tasks?ids[]=1&ids[]=2&ids[]=3
See https://angular.io/guide/http#url-parameters

Node.js node-postgres get JSON objects from API call

I have followed the node-postgres.org instruction at https://node-postgres.com/guides/async-express to connect via async/await to my postgres table users.
Navigating to localhost:3000/users/1 will return the JSON string for user 1 in the browser. I have extended this a bit to return all users at localhost:3000/users. My routes/user.js script is:
const Router = require('express-promise-router')
const db = require('../db')
// create a new express-promise-router
// this has the same API as the normal express router except
// it allows you to use async functions as route handlers
const router = new Router()
// export our router to be mounted by the parent application
module.exports = router
router.get('/:id', async (req, res) => {
console.log('Where id = ');
const { id } = req.params
const { rows } = await db.query('SELECT * FROM users WHERE id = $1', [id])
res.send(rows[0])
})
router.get('/', async (req, res) => {
console.log('*');
const { rows } = await db.all('SELECT * FROM users')
res.send(rows)
})
the index for this route at routes/index.js is simply:
const users = require('./user')
module.exports = (app) => {
app.use('/users', users)
}
and the db.query() and db.all() functions that I am awaiting are in db/index.js:
const { Pool } = require('pg')
const pool = new Pool()
module.exports = {
query: (text, params) => pool.query(text, params),
all: (text) => pool.query(text)
}
The routes are required in my main app.js file:
// ./app.js
const express = require('express')
const mountRoutes = require('./routes')
const cons = require('consolidate')
const path = require('path')
const bodyParser = require('body-parser')
const app = express()
mountRoutes(app)
// Assign Dust Engine to .dust files
app.engine('dust', cons.dust);
// Set .dust as the default extension
app.set('view engine', 'dust');
app.set('views', __dirname + '/views');
// Set Public Folder
app.use(express.static(path.join(__dirname, 'public')));
//Body parser and Middleware
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
extended: false
}));
app.get('/', function(reg, res) {
console.log('Root');
res.render('index', {hallo:'test'})
});
//Server
app.listen(3000, function() {
console.log('Server Started on Port 3000');
});
So far this works beautifully! I get the JSON strings that I want and I can build upon this sort of API by extending my routes and queries.
Question:
How can I return my JSON object rows back to app.js to res.render() it there?
or
Can I do something like this anywhere in my app:
jsonVar = GetMyJson('/users/1');
console.log(jsonVar);
returns:
[
{
"id": 1,
"usr_name": "Michael"
},
{
"id": 2,
"usr_name": "Thomas"
},
{
"id": 3,
"usr_name": "Paul"
}
]
I could then pass whatever route and parameters I want into GetMyJson() and deal with the resulting JSON.
This may be a trivial question for javascript devs ...
Thanks!
EDIT 21/12/2017
I have created a frontend script called graphs.js that simply logs my result when i call the fuction api('/user/1').
var el = document.getElementById("clickMe");
if (el.addEventListener)
el.addEventListener("click", api, false);
else if (el.attachEvent)
el.attachEvent('onclick', api);
var api = function(what){
// Action
sendRequest(what, function(result){
if(result){
log(result);
}
})
}
var apiEndpoint = 'http://localhost:3000/'
function sendRequest(_path, cb) {
var oReq = new XMLHttpRequest();
oReq.open('GET', apiEndpoint+_path);
oReq.onreadystatechange = function() {
if (this.readyState === 4) {
cb(JSON.parse(this.response));
}
else{
cb(null);
}
}
oReq.send();
}
function log(msg){
console.log(msg);
}
BUT
Is that a proper way of doing it in javascript?
The way to go about it would be something like this:
router.get('/', async (req, res) => {
console.log('*');
const { rows } = await db.all('SELECT * FROM users')
res.render('user', rows)
});
Instead of res.send you do res.render
You have to get it from database. Making self call will not be an ideal solution. So you can do following
const db = require('../db') // fix the location of db.js
app.get('/', function(req, res) {
db.all('SELECT * FROM users').then(function({ rows }) {
res.render('index', rows)
})
})
Best would be to make an userRepository.js and add code related to db over there. Then use that repository at both places.

How to use MVC and include files in my node app

I Have a Node app, I have three files and am trying to structure my node in a MVC pattern.
I want a way to put all my requires and variables in my server.js all the routes in my routes.js and my functions in my controller.js.
My router is fine and works.
How do I include the functions from controller in my server file
I have:
server.js
var configure = require('./router');
var express = require('express');
var app = express();
var port = process.env.PORT || 8080;
// get an instance of router
var router = express.Router();
configure(router);
var request = require('request');
var nodePardot = require('node-pardot');
var bodyParser = require('body-parser');
var rp = require('request-promise');
// Start the server
app.listen(port);
app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({extended: true})); // support encoded bodies
console.log('Test server started! At http://localhost:' + port); // Confirms server start
//
// // START THE SERVER
// // ==============================================
app.listen(port);
console.log('Server has started!! ' + port);
// apply the routes to our application
app.use('/', router);
router.js`
module.exports = function (router) {
// route middleware that will happen on every request
router.use(function (req, res, next) {
// log each request to the console
console.log(req.method, req.url);
// continue doing what we were doing and go to the route
next();
});
// home page route (http://localhost:8080)
router.get('/', function (req, res) {
res.send('im the home page!');
});
router.get('/login', function (req, res) {
res.send('this is the login form');
})
// process the form (POST http://localhost:8080/login)
.post('/login', function (req, res) {
console.log('processing'); // shows on console when post is made
res.send('processing the login form!'); // output on postman
});
};
controller.js
var password = 'gf.09';
var userkey = 'dfgg';
var emailAdmin = 'rt.r#rt.co.uk';
// Start the server
app.listen(port);
app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({extended: true})); // support encoded bodies
console.log('Test server started! At http://localhost:' + port); // Confirms server start
var firstFunction = function () {
return new Promise (function (resolve) {
setTimeout(function () {
app.post('/back-end/test', function (req, res) {
console.log(req.body);
var login = req.body.LoginEmail;
res.send(login);
resolve({
data_login_email: login
});
});
console.error("First done");
}, 2000);
});
};
var secondFunction = function () {
return new Promise (function (resolve) {
setTimeout(function () {
nodePardot.PardotAPI({
userKey: userkey,
email: emailAdmin,
password: password,
DEBUG: false
}, function (err, client) {
if (err) {
// Authentication failed
console.error("Authentication Failed", err);
} else {
// Authentication successful
var api_key = client.apiKey;
console.log("Authentication successful !", api_key);
resolve({data_api: api_key});
}
});
console.error("Second done");
}, 2000);
});
};
function thirdFunction(result) {
return new Promise (function () {
setTimeout(function () {
var headers = {
'User-Agent': 'Super Agent/0.0.1',
'Content-Type': 'application/x-www-form-urlencoded'
};
// Configure the request
var api = result[1].data_api;
var login_email = result[0].data_login_email;
var options = {
url: 'https://pi.pardot.com/api/prospect/version/4/do/read',
method: 'POST',
headers: headers,
form: {
'email': login_email,
'user_key': userkey,
'api_key': api
},
json: true // Automatically stringifies the body to JSON
};
// Start the request
rp(options)
.then(function (parsedBody) {
console.error(login_email, "Is a user, login pass!");
})
.catch(function (err) {
console.error("fail no such user");
// res.status(400).send()
});
console.error("Third done");
}, 3000);
}
);
}
// sequence of functions
Promise.all([firstFunction(), secondFunction()])
.then(thirdFunction);
What I have tried
var routers = require('./router');
var controller = require('./test');
// var controller = require('./test.js','./router' );
var express = require('express');
var request = require('request');
var nodePardot = require('node-pardot');
var bodyParser = require('body-parser');
var rp = require('request-promise');
var app = express();
var port = process.env.PORT || 8080;
var router = express.Router();
routers(router);
controller(Promise);
and
module.exports = function (Promise) {
all functions
}
Problem is some of the variables are not available to controller.js so i get errors such as :
app.post('/back-end/controller', function (req, res) {
^
This is dead simple use same logic as you applied in your router.js.
Use something like below in controller.js:
exports.function_name = function(params, ...){
. . .
}
Then access these function by importing the controller.js
var controller = require('./controller.js');
controller.function_name(param..) # execute with required params and callback
If you want to return an object then you can do module.exports
module.exports = Promise.all([firstFunction(), secondFunction()]) .then(thirdFunction);
The controller object contain a promise now so
var controller = require('./controller.js');
controller object directly can be used as a promise no need to call a function now.
A better alternative is to export all the functions from controller.js and then in app.js you can use them with promise.
Promise.all([controller.firstFunction(), controller.secondFunction()]) .then(controller.thirdFunction);

Passing Mongo DB Object DB to Express Middleware

I am having problems trying to access the "DB" database object that is created when the MongoDB client module connects to my MongoDB database.
At the moment I am getting an error stating that, within data.js, 'db' is not defined. I understand why this is - the db object is not being "passed" through to the router and then subsequently through to the controller.
What is the best way to do this?
I have tried to pass the "db" object through to the router (dataRoutes.js) but I cannot figure how to make this accessible to the controller (data.js). Could someone please help?
Please note I have not included the other routes and controllers but they simply submit a Form via the POST method to /data/submit . The controller below is meant to write this form data to the MongoDB database.
Here is the relevant code:
app.js
var express = require('express');
var path = require('path')
var MongoClient = require('mongodb').MongoClient;
var bodyParser = require('body-parser');
var app = express();
var routes = require('./routes/index');
var dataRoutes = require('./routes/dataRoutes');
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
MongoClient.connect("mongodb://localhost:27017/m101", function(err, db) {
if(err) throw err;
console.log("Successfully connected to MongoDB.");
app.use('/', routes); // Use normal routes for wesbite
app.use('/data', dataRoutes);
app.get('/favicon.ico', function(req, res) {
res.send(204);
});
app.use(function(req, res, next) {
var err = new Error('Oops Page/Resource Not Found!');
err.status = 404;
next(err); //Proceed to next middleware
});
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
// update the error responce, either with the error status
// or if that is falsey use error code 500
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}
app.use(function(err, req, res, next) {
console.log('Error');
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});
var server = app.listen(3000, function() {
var port = server.address().port;
console.log("Express server listening on port %s.", port);
});
});
dataRoutes.js
// router
var express = require('express');
var router = express.Router();
// controller references
var ctrlsData = require('../controllers/data');
router.post('/submit', ctrlsData.submit);
module.exports = router;
data.js
var MongoClient = require('mongodb').MongoClient;
var sendJsonResponse = function(res, status, content) {
res.status(status);
res.json(content);
};
module.exports.submit = function(req, res) {
var title = req.body.title;
var year = req.body.year;
var imdb = req.body.imdb;
/*
console.log('submitted');
console.log(req.body);
sendJsonResponse(res, 201, {title,year,imdb});
*/
var title = req.body.title;
var year = req.body.year;
var imdb = req.body.imdb;
if ((title == '') || (year == '') || (imdb == '')) {
sendJsonResponse(res, 404, {
"message": "Title, Year and IMDB Reference are all required."
});
} else {
db.collection('movies').insertOne(
{ 'title': title, 'year': year, 'imdb': imdb },
function (err, r) {
if (err) {
sendJsonResponse(res, 400, err);
} else {
sendJsonResponse(res, 201, "Document inserted with _id: " + r.insertedId + {title,year,imdb});
}
}
);
}
};
Create a db variable that reference mongodb in app.js :
MongoClient.connect("mongodb://localhost:27017/m101", function(err, db) {
app.db = db;
//.....
});
In data.js, access db from req.app :
module.exports.submit = function(req, res) {
req.app.db.collection('movies').insertOne({ 'title': title, 'year': year, 'imdb': imdb },
function(err, r) {}
)
};
The accepted answer isn't quite correct. You shouldn't attach custom objects to the app object. That's what app.locals is for. Plus, the accepted answer will fail when using Typescript.
app.locals.db = db;
router.get('/foo', (req) => {
req.app.locals.db.insert('bar');
});
Sure, it's longer. But you get the assurance that future updates to ExpressJS will not interfere with your object.
I understand that the answer of #Bertrand is functional, but it is not usually recommended. The reason being that, from a software point of view, you should have a better separation in your software.
app.js
var express = require('express');
var path = require('path')
var MongoClient = require('mongodb').MongoClient;
var bodyParser = require('body-parser');
var app = express();
var routes = require('./routes/index');
var dataRoutes = require('./routes/dataRoutes');
var DB = require('./db.js');
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
DB.Init("mongodb://localhost:27017/m101")
.then(() => {
console.log("Successfully connected to MongoDB.");
app.use('/', routes); // Use normal routes for wesbite
app.use('/data', dataRoutes);
app.get('/favicon.ico', function(req, res) {
res.send(204);
});
var server = app.listen(3000, function() {
var port = server.address().port;
console.log("Express server listening on port %s.", port);
});
})
.catch((e) => {
console.log("Error initializing db");
});
db.js
var _db = null;
module.exports = {
Init: (url) => {
return new Promise((resolve, reject) => {
if (!url)
reject("You should provide a URL");
MongoClient.connect("mongodb://localhost:27017/m101", function(err, db) {
if(err) reject(err);
_db = db;
resolve(); // Or resolve(db) if you wanna return the db object
});
});
},
Submit: (req, res, next) => {
// Whatever goes. You have access to _db here, too!
}
};
in data.js
var DB = require('../db.js');
router.post('/submit', DB.submit);
Finally, even this answer can be improved as you are not usually advised to wait for the DB to connect, otherwise, you are losing the advantage of using ASync procs.
Consider something similar to here in app.js:
Promise.resolve()
.then(() => {
// Whatever DB stuff are
// DB.Init ?
})
.then(() => {
// Someone needs routing?
})
...
.catch((e) => {
console.error("Ther app failed to start");
console.error(e);
});
I understand that in the last sample, you can not instantly query DB as it may not have connected yet, but this is a server, and users are usually expected to wait for your DB to init. However, if you wanna more proof solution, consider implementing something yourself in DB.submit to wait for the connect. Or, you can also use something like mongoose.

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