Dynamic CRUD functions with Node, Express and Pug - node.js

Question

Hi I am new to backend node applications and I am trying to create a clean API driven node.js app without frameworks by working with scripts and pug template engine.
I have created a serve.js file with all the necessary code:
var express = require('express');
var app = express();
var path = require('path');
var favicon = require('serve-favicon');
const bodyParser = require("body-parser");
var mongodb = require("mongodb");
const MongoClient = require('mongodb').MongoClient
var ObjectID = mongodb.ObjectID;
var indexRoutes = require('./routes/index');
var thePort = process.env.PORT || 5000;
var SECTIONS_COLLECTION = "sections";
//make results available as json
app.use(bodyParser.json());
//External database identifier
var db;
//Path to the database with URI
var dbpath = process.env.MONGODB_URI || 'mongodb://heroku_fmvc5nhk:5rqdhjqc2orjhen7knanjpfmd7#ds014586.mlab.com:19986/heroku_fmvc5nhk';
// Connect to the database before starting the application server.
mongodb.MongoClient.connect(dbpath, function (err, database) {
if (err) {
console.log(err);
process.exit(1);
}
// Save database object from the callback for reuse.
db = database;
console.log("Database connection ready");
//static folder directory
app.use(express.static(__dirname + '/dist'));
// Initialize the app.
var server = app.listen(process.env.PORT || thePort, function () {
var port = server.address().port;
console.log("App now running on port", port);
});
});
// Generic error handler used by all endpoints.
function handleError(res, reason, message, code) {
console.log("ERROR: " + reason);
res.status(code || 500).json({"error": message});
}
//set up routes directory
app.use('/', indexRoutes);
// Views and Template Engine
//app.set('views', __dirname + './views');
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
// sections API ROUTES:
/* "/api/sections"
* GET: finds all sections
* POST: creates a new contact
*/
app.get("/api/sections", function(req, res) {
db.collection(SECTIONS_COLLECTION).find({}).toArray(function(err, docs) {
if (err) {
handleError(res, err.message, "Failed to get sections.");
} else {
res.status(200).json(docs);
}
});
});
app.post("/api/sections", function(req, res) {
var newContact = req.body;
if (!req.body.name) {
handleError(res, "Invalid user input", "Must provide a name.", 400);
}
db.collection(sections_COLLECTION).insertOne(newContact, function(err, doc) {
if (err) {
handleError(res, err.message, "Failed to create new contact.");
} else {
res.status(201).json(doc.ops[0]);
}
});
});
/* "/api/sections/:id"
* GET: find contact by id
* PUT: update contact by id
* DELETE: deletes contact by id
*/
app.get("/api/sections/:id", function(req, res) {
db.collection(SECTIONS_COLLECTION).findOne({ _id: new ObjectID(req.params.id) }, function(err, doc) {
if (err) {
handleError(res, err.message, "Failed to get contact");
} else {
res.status(200).json(doc);
}
});
});
app.put("/api/sections/:id", function(req, res) {
var updateDoc = req.body;
delete updateDoc._id;
db.collection(SECTIONS_COLLECTION).updateOne({_id: new ObjectID(req.params.id)}, updateDoc, function(err, doc) {
if (err) {
handleError(res, err.message, "Failed to update contact");
} else {
updateDoc._id = req.params.id;
res.status(200).json(updateDoc);
}
});
});
app.delete("/api/sections/:id", function(req, res) {
db.collection(SECTIONS_COLLECTION).deleteOne({_id: new ObjectID(req.params.id)}, function(err, result) {
if (err) {
handleError(res, err.message, "Failed to delete contact");
} else {
res.status(200).json(req.params.id);
}
});
});
In my views\about.pug template I reference my JSON object's contents.
//--about.pug
extends index.pug
block div.root
h2= #{about.heading}
h3= #{about.summary}
p #{about.content}
In my routesroutes/index.js I have pre-existing "flat" examples with pug then one dynamic about example:
var express = require('express');
var router = express.Router();
router.get('/', function (req, res) {
res.render(
'index',
{
title: 'Welcome to Awesome Place',
header: 'Home',
summary: 'This is my home. It can\'t be any simpler'
}
)
})
Dynamic example:
//About
router.get('/about', function (req, res) {
//retrieve all home from Mongo
db.collection(SECTIONS_COLLECTION).find({"name": "about"}), function (err, about) {
if (err) {
handleError(res, err.message, "Failed to get sections.");
} else {
res.render('about', {})
console.log(result)
}
}
})
The above is returning a db is not defined error.
If var indexRoutes = require('./routes/index'); is required as part of my server.js file, why can't it find the value of db?
UPDATED CODE (TOO MANY ERRORS)
//server.js
//APP Dependences
var express = require('express');
var app = express();
var path = require('path');
var favicon = require('serve-favicon');
var indexRoutes = require('./routes/index');
var bodyParser = require("body-parser");
//PORT
var thePort = process.env.PORT || 5000;
// Views and Template Engine
//app.set('views', __dirname + './views');
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
//Documents
app.use(bodyParser.json());
//static folder directory
app.use(express.static(__dirname + '/dist'));
//set up routes directory
app.use('/', indexRoutes);
// Catch errors
app.use(function(req, res, next) {
res.status(404).sendFile(process.cwd() + '/app/views/404.htm');
});
// Initialize the app.
var server = app.listen(process.env.PORT || thePort, function () {
var port = server.address().port;
console.log("App now running on port", port);
});
});
var mongodb = require("mongodb");
const MongoClient = require('mongodb').MongoClient
var ObjectID = mongodb.ObjectID;
var SECTIONS_COLLECTION = "sections";
//External database identifier
var db;
//Path to the database with URI
var dbpath = process.env.MONGODB_URI || 'mongodb://heroku_fmvc5nhk:5rqdhjqc2ovanbfd7knanjpfmd7#ds019986.mlab.com:19986/heroku_fmvc5nhk';
// Connect to the database before starting the application server.
mongodb.MongoClient.connect(dbpath, function (err, database) {
if (err) {
console.log(err);
process.exit(1);
}
// Save database object from the callback for reuse.
db = database;
console.log("Database connection ready");
// Initialize the app.
var server = app.listen(process.env.PORT || thePort, function () {
var port = server.address().port;
console.log("App now running on port", port);
});
// Generic error handler used by all endpoints.
function handleError(res, reason, message, code) {
console.log("ERROR: " + reason);
res.status(code || 500).json({"error": message});
}
//db.js
var express = require('express');
var mongodb = require("mongodb");
var MongoClient = require('mongodb').MongoClient
var ObjectID = mongodb.ObjectID;
var assert = require('assert');
//Path to the database with
var dbpath = process.env.MONGODB_URI || 'mongodb://heroku_fmvc5nhk:5rqdhjqc2ovahen7knanjpfmd7#ds019986.mlab.com:19986/heroku_fmvc5nhk';
//Get the section
var SECTIONS_COLLECTION = "sections";
// Use connect method to connect to the server
var database;
function connectMongo(cb){
MongoClient.connect(dbpath , function(err, database) {
assert.equal(null, err);
console.log("Connected successfully to server");
cb(database);
});
}
module.exports = connectMongo;
//routes/index.js
var express = require('express');
var router = express.Router();
var connectDB = require ('../db')
router.get('/', function (req, res) {
res.render(
'index',
{
title: 'Welcome to Awesome Place',
header: 'Home',
summary: 'This is my home. It can\'t be any simpler'
}
)
})
connectMongo(function(database){
//About
router.get('/about', function (req, res) {
//retrieve all home from Mongo
database.collection(SECTIONS_COLLECTION).find({"name": "about"}), function (err, about) {
if (err) {
handleError(res, err.message, "Failed to get sections.");
} else {
res.render('about', {})
console.log(result)
}
}
})
}
router.get('/work', function (req, res) {
res.render(
'work',
{
title: 'Work, Work, Work , Work...',
header: 'Work life',
summary: 'My first work for this bitch',
imgUrl: '/img/firaz.jpg'
}
)
})
router.get('/contact', function (req, res) {
res.render(
'contact',
{
title: 'Contact Me Any Time',
header: 'Contact Me Any Time',
summary: 'Fill the form below to be contacted'
}
)
})
module.exports = router;

Answer 1

Because db variable is not global by requiring var indexRoutes = require('./routes/index'); you are importing the objects from routes/index file to server not the other way around.
what you can do is make your db variable global global.db and access it anywhere or create a seperate file for mongo db connection and require that in routes file
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
function connectMongo(cb){
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
cb(db);
});
}
module.exports = connectMongo;
This github Repo got good structure for mongoDB
https://github.com/OmarElGabry/chat.io