Using a Router Instance
Let's refactor app.js
to use a Router
object.
Create a new router object and assign it to the router
variable.
var router = express.Router();
When we are done, our router
will be mounted on the /cities
path. With this in mind, change app.route('/cities')
to use router
and map requests to the root path.
app.route('/cities')
.get(function (request, response) {
if(request.query.search){
response.json(citySearch(request.query.search));
}else{
response.json(cities);
}
}) //to router.route('/')
.get(function (request, response) {
if(request.query.search){
response.json(citySearch(request.query.search));
}else{
response.json(cities);
}
})
Likewise, let's move our '/cities/:name'
route to our router
. Remember to update the path.
app.route('/cities/:name')
.get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo){
response.json(cityInfo);
}else{
response.status(404).json("City not found");
}
}) .delete(function (request, response) {
if(cities[request.cityName]){
delete cities[request.cityName];
response.sendStatus(200);
}else{
response.sendStatus(404);
}
}); //to router.route('/:name')
.get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo){
response.json(cityInfo);
}else{
response.status(404).json("City not found");
}
}) .delete(function (request, response) {
if(cities[request.cityName]){
delete cities[request.cityName];
response.sendStatus(200);
}else{
response.sendStatus(404);
}
});
Our router
is now ready to be used by app
. Mount our new router
under the /cities
path.
app.use('/cities', router);
var express = require('express');
var app = express(); var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false }); // In memory store for the
// cities in our application
var cities = {
'Lotopia': 'Rough and mountainous',
'Caspiana': 'Sky-top island',
'Indigo': 'Vibrant and thriving',
'Paradise': 'Lush, green plantation',
'Flotilla': 'Bustling urban oasis'
}; app.param('name', function (request, response, next) {
request.cityName = parseCityName(request.params.name);
}); var router = express.Router();
app.use('/cities', router);
router.route('/')
.get(function (request, response) {
if(request.query.search){
response.json(citySearch(request.query.search));
}else{
response.json(cities);
}
}) .post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4){
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
}else{
response.status(400).json('Invalid City');
}
}); router.route('/:name')
.get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo){
response.json(cityInfo);
}else{
response.status(404).json("City not found");
}
}) .delete(function (request, response) {
if(cities[request.cityName]){
delete cities[request.cityName];
response.sendStatus(200);
}else{
response.sendStatus(404);
}
}); // Searches for keyword in description
// and returns the city
function citySearch(keyword) {
var regexp = RegExp(keyword, 'i');
var result = cities.filter(function (city) {
return city.match(regexp);
}); return result;
} // Adds a new city to the
// in memory store
function createCity(name, description){
cities[name] = description;
return name;
} // Uppercase the city name.
function parseCityName(name){
var parsedName = name[0].toUpperCase() + name.slice(1).toLowerCase();
return parsedName;
} app.listen(3000);
All HTTP Verbs
What function would you call to match all HTTP verbs?
Answer:
app.all();
Using All
Let's use the app.all()
method to handle the name
parameter instead of app.param()
.
Add a call to all()
for our router's '/:name'
route. Pass a callback function that accepts request
, response
, and next
.
router.route('/:name')
.all(function(request, response, next){ })
Now let's take our logic from the callback function passed to app.param()
and move it to our all()
callback.
router.route('/:name')
.all(function(request, response, next){
request.cityName = parseCityName(request.params.name);
})
var express = require('express');
var app = express(); var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false }); // In memory store for the cities in our application
var cities = {
'Lotopia': 'Rough and mountainous',
'Caspiana': 'Sky-top island',
'Indigo': 'Vibrant and thriving',
'Paradise': 'Lush, green plantation',
'Flotilla': 'Bustling urban oasis'
}; // Searches for keyword in description and returns the city
function citySearch(keyword) {
var regexp = RegExp(keyword, 'i');
var result = cities.filter(function (city) {
return city.match(regexp);
}); return result;
} // Adds a new city to the in memory store
function createCity(name, description) {
cities[name] = description;
return name;
} // Uppercase the city name.
function parseCityName(name) {
var parsedName = name[0].toUpperCase() + name.slice(1).toLowerCase();
return parsedName;
} var router = express.Router(); router.route('/')
.get(function (request, response) {
if(request.query.search) {
response.json(citySearch(request.query.search));
} else {
response.json(cities);
}
}) .post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4) {
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
} else {
response.status(400).json('Invalid City');
}
}); router.route('/:name')
.all(function(request, response, next){
request.cityName = parseCityName(request.params.name);
})
.get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo) {
response.json(cityInfo);
} else {
response.status(404).json("City not found");
}
}) .delete(function (request, response) {
if(cities[request.cityName]) {
delete cities[request.cityName];
response.sendStatus(200);
} else {
response.sendStatus(404);
}
}); app.use('/cities', router); app.listen(3000);
Creating a Router Module
Our single application file is growing too long. It's time we extract our routes to a separate Node module under the routes folder.
Move our router
and its supporting code from app.js
toroutes/cities.js
.
routes/cities.js
var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false }); // In memory store for the
// cities in our application
var cities = {
'Lotopia': 'Rough and mountainous',
'Caspiana': 'Sky-top island',
'Indigo': 'Vibrant and thriving',
'Paradise': 'Lush, green plantation',
'Flotilla': 'Bustling urban oasis'
}; var router = express.Router(); router.route('/')
.get(function (request, response) {
if(request.query.search){
response.json(citySearch(request.query.search));
}else{
response.json(cities);
}
}) .post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4){
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
}else{
response.status(400).json('Invalid City');
}
}); router.route('/:name')
.all(function (request, response, next) {
request.cityName = parseCityName(request.params.name);
}) .get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo){
response.json(cityInfo);
}else{
response.status(404).json("City not found");
}
}) .delete(function (request, response) {
if(cities[request.cityName]){
delete cities[request.cityName];
response.sendStatus(200);
}else{
response.sendStatus(404);
}
}); // Searches for keyword in description
// and returns the city
function citySearch(keyword) {
var regexp = RegExp(keyword, 'i');
var result = cities.filter(function (city) {
return city.match(regexp);
}); return result;
} // Adds a new city to the
// in memory store
function createCity(name, description){
cities[name] = description;
return name;
} // Uppercase the city name.
function parseCityName(name){
var parsedName = name[0].toUpperCase() + name.slice(1).toLowerCase();
return parsedName;
}
export our router
object so other files can have access to it. Remember, Node - therefore Express - uses the CommonJS module specification.
module.exports = router;
Our cities routes module is now ready to be used from app.js. Require the new routes/cities module from app.js
and assign it to a variable calledrouter
;
app.js
var router = require('./routes/cities');
app.js
var express = require('express');
var app = express();
var router = require('./routes/cities'); app.use('/cities', router);
app.listen(3000);
routes/cities.js
var express = require('express');
var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false }); // In memory store for the
// cities in our application
var cities = {
'Lotopia': 'Rough and mountainous',
'Caspiana': 'Sky-top island',
'Indigo': 'Vibrant and thriving',
'Paradise': 'Lush, green plantation',
'Flotilla': 'Bustling urban oasis'
}; var router = express.Router(); router.route('/')
.get(function (request, response) {
if(request.query.search){
response.json(citySearch(request.query.search));
}else{
response.json(cities);
}
}) .post(parseUrlencoded, function (request, response) {
if(request.body.description.length > 4){
var city = createCity(request.body.name, request.body.description);
response.status(201).json(city);
}else{
response.status(400).json('Invalid City');
}
}); router.route('/:name')
.all(function (request, response, next) {
request.cityName = parseCityName(request.params.name);
}) .get(function (request, response) {
var cityInfo = cities[request.cityName];
if(cityInfo){
response.json(cityInfo);
}else{
response.status(404).json("City not found");
}
}) .delete(function (request, response) {
if(cities[request.cityName]){
delete cities[request.cityName];
response.sendStatus(200);
}else{
response.sendStatus(404);
}
}); // Searches for keyword in description
// and returns the city
function citySearch(keyword) {
var regexp = RegExp(keyword, 'i');
var result = cities.filter(function (city) {
return city.match(regexp);
}); return result;
} // Adds a new city to the
// in memory store
function createCity(name, description){
cities[name] = description;
return name;
} // Uppercase the city name.
function parseCityName(name){
var parsedName = name[0].toUpperCase() + name.slice(1).toLowerCase();
return parsedName;
} module.exports = router;