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[Express] Level 2: Middleware -- 1
Mounting Middleware
Given an application instance is set to the app variable, which of the following function calls would you use to mount a middleware called logger ?
Answer:
app.use(logger);
Default Middleware
What is the only middleware that‘s shipped with Express 4?
Answer: express-static
Express Static
Change the code in app.js to use the express-static middleware instead of the response.sendFile() function.
var express = require(‘express‘);var app = express();app.get(‘/‘, function (request, response) { response.sendFile(__dirname + ‘/public/index.html‘);});app.get(‘/cities‘, function(req, res){ var cities = [‘Lotopia‘, ‘Caspiana‘, ‘Indigo‘]; res.send(cities);});app.listen(3001);
Remove our app.get() containing the root ‘/‘ route.
Mount the static middleware and serve files under the public directory.
Answer:
var express = require(‘express‘);var app = express();/*app.get(‘/‘, function (request, response) { response.sendFile(__dirname + ‘/public/index.html‘);});*///cd publicapp.use(express.static(‘public‘));app.get(‘/cities‘, function(req, res){ var cities = [‘Lotopia‘, ‘Caspiana‘, ‘Indigo‘]; res.send(cities);});app.listen(3001);
Script Tags
Now we can add some client side javascript by including thejquery.js and client.js files.
Within index.html, include jquery.js using a <script> tag.
Within index.html, include client.js using a <script> tag.
Now in the client.js file, complete the code for the $.get function so that it calls the /cities URL path, and then runs the appendToList function.
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Cities</title></head><body> <h1>Cities</h1> <ul class=‘city-list‘></ul> <script src="jquery.js"></script> <script src="client.js"></script></body></html>
Now in the client.js file, complete the code for the $.get function so that it calls the /cities URL path, and then runs the appendToList function.
$(function(){ $.get(‘/cities‘, appendToList ); function appendToList(cities) { var list = []; for(var i in cities){ list.push($(‘<li>‘, { text: cities[i] })); } $(‘.city-list‘).append(list); }});
[Express] Level 2: Middleware -- 1