一、express
可以做：web application、api...
特性：
- 适合写简单的路由系统
- 集成很多模板引擎
- 中间件系统
二、请求与响应
var express = require('express'); var app = express(); //据说第二个参数是一个中间件方法 app.get('/', function(req, res) { //学会查api来学习更多知识，学会学习官方api文档 var resObj = req.method; //send可以发送字符串、json（包含自动stringify）对象和数组 res.send(resObj); }) app.listen(3000); console.log('listening to port 3000');
三、路由参数
server.js
var express = require('express'); var app = express(); app.get('/profile/:id/user/:name', function(req, res) { console.dir(req.params); res.send('you requested to a profile page with the name of ' + req.params.name); }) app.listen(3000); console.log('listening to port 3000');
terminal
chrome
四、查询字符串
server.js
app.get('/', function(req, res) {
console.dir(req.query);
res.send('home page:' + req.query.find);
})
terminal
chrome
五、post请求和postman工具
同时处理x-www-form和json
var express = require('express'); var bodyparser = require('body-parser'); var app = express(); //create application/json parser var jsonParser = bodyparser.json(); //create application/x-www-form-urlencoded parser var urlencodedParser = bodyparser.urlencoded({ extended: false}) app.post('/', urlencodedParser,function (req, res) { console.dir(req.body); res.send(req.body.name); }) app.post('/upload', jsonParser, function (req, res) { console.dir(req.body); res.send(req.body.name); })
参考链接：github/express/body-parser
六、上传文件
form.html
<body>
<form action="/upload" method="post" enctype="multipart/form-data">
<h2>单图上传</h2>
<input type="file" name="logo">
<input type="submit" value="submit">
</form>
</body>
server.js
var express = require('express'); var bodyparser = require('body-parser'); var fs = require('fs'); var multer = require('multer'); var upload = multer({ dest: 'uploads/'}); var app = express(); //create application/json parser var jsonParser = bodyparser.json(); //create application/x-www-form-urlencoded parser var urlencodedParser = bodyparser.urlencoded({ extended: false}) app.get('/', function(req, res) { console.dir(req.query); res.send('home page:' + req.query.find); }) app.get('/form', function(req, res) { var form = fs.readFileSync('./form.html', { encoding: 'utf8'}); res.send(form); }) app.post('/', urlencodedParser,function (req, res) { console.dir(req.body); res.send(req.body.name); }) app.post('/upload', upload.single('logo'),function (req, res) { res.send({'ret_code': 0}); }) app.listen(3000); console.log('listening to port 3000');
结构变化
参考链接：github/express/multer
tips:
app.get('/form', function(req, res) {
var form = fs.readFileSync('./form.html', { encoding: 'utf8'});
res.send(form);
})
等价于
app.get('/form', function(req, res) {
res.sendFile(__dirname + '/form.html');
})
七、模板引擎
引入
app.set('view engine', 'ejs');
使用
server.js
app.get('/form/:name', function(req, res) {
var person = req.params.name;
res.render('form', { person: person});
res.sendFile(__dirname + '/form.html');
})
form.ejs
<h1><%= person %></h1>
遍历数组
<ul>
<%= data.hobbie.forEach(function(item){ %>
<li>
<%= item %>
</li>
<%= }) %>
</ul>
公用模板
使用
<%- include('partials/header.ejs') -%>
about.ejs
<body>
<%- include('partials/header.ejs') -%>
</body>
渲染
app.get('/about', function(req, res) {
var data = {age: 29, job: 'programmer', hobbie: ['eating', 'fighting', 'fishing']};
res.render('about', { data: data});
})
参考链接：ejs.co、pug
八、中间件
解释：请求与响应之间的处理过程是中间件发挥作用的地方。
好处：共用模块、全局性的操作
类型：
- 应用级中间件
- 路由级中间件
- 错误层次中间件
- 内置中间件
- 第三方中间件
执行顺序
app.use(function(req, res, next){ console.log('1'); next(); console.log('3'); }) app.use(function(req, res, next){ console.log('2'); })
路由中间件
server.js
var indexRouter = require('./routes/index.js'); var userRouter = require('./routes/user.js'); app.use('/', indexRouter); app.use('/users', userRouter);
./route/index.js
var express = require('express'); var router = express.Router(); router.get('/', function(req, res, next) { res.send('root'); }) module.exports = router;
./route/user.js
var express = require('express'); var router = express.Router(); router.get('/', function(req, res, next) { res.send('user'); }) module.exports = router;
体会：用中间件写路由的好处
参考链接：express/using-middleware