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[Express] Level 5: Route file
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); } })//torouter.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); } });//torouter.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 applicationvar 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 cityfunction 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 storefunction 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 applicationvar 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 cityfunction 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 storefunction 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 applicationvar 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 cityfunction 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 storefunction 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 applicationvar 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 cityfunction 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 storefunction 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;
[Express] Level 5: Route file
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