Express provide a higher level interface of http module.
Install express:
$ npm install express --save
these important modules will be installed with express.
-
body-parser: middleware of Node.js, to handle JSON, Raw, Text and URL encoding data. -
cookie-parser: tool to parse cookie. we can get cookie by req.cookies, and parse into object -
multer: middleware of Node.js. to handle form data likeenctype="multipart/form-data"
$ npm install body-parser --save
$ npm install cookie-parser --save
$ npm install multer --save
Example
//express_demo.js
var express = require('express');
var app = express();
app.get('/', function (req, res) {
res.send('Hello World');
})
var server = app.listen(80, function () {
var host = server.address().address
var port = server.address().port
console.log("应用实例，访问地址为 http://%s:%s", host, port)
})
Request and Response
Request:
-
req.app：当callback为外部文件时，用req.app访问express的实例 -
req.baseUrl：获取路由当前安装的URL路径 -
req.body/req.cookies：获得「请求主体」/ Cookies -
req.fresh/req.stale：判断请求是否还「新鲜」 -
req.hostname/req.ip：获取主机名和IP地址 -
req.originalUrl：获取原始请求URL -
req.params：获取路由的parameters -
req.path：获取请求路径 -
req.protocol：获取协议类型 -
req.query：获取URL的查询参数串 -
req.route：获取当前匹配的路由 -
req.subdomains：获取子域名 -
req.accepts()：检查可接受的请求的文档类型 -
req.acceptsCharsets/req.acceptsEncodings/req.acceptsLanguages：返回指定字符集的第一个可接受字符编码 -
req.get()：获取指定的HTTP请求头 -
req.is()：判断请求头Content-Type的MIME类型
Response:
-
res.app：同req.app一样 -
res.append()：追加指定HTTP头 -
res.set(): 在res.append()后将重置之前设置的头 -
res.cookie(name，value [，option])：设置Cookie -
opition: domain / expires / httpOnly / maxAge / path / secure / signed -
res.clearCookie()：清除Cookie -
res.download()：传送指定路径的文件 -
res.get()：返回指定的HTTP头 -
res.json()：传送JSON响应 -
res.jsonp()：传送JSONP响应 -
res.location()：只设置响应的Location HTTP头，不设置状态码或者close response -
res.redirect()：设置响应的Location HTTP头，并且设置状态码302 -
res.send()：传送HTTP响应 -
res.sendFile(path [，options] [，fn])：传送指定路径的文件 -会自动根据文件extension设定Content-Type -
res.set()：设置HTTP头，传入object可以一次设置多个头 -
res.status()：设置HTTP状态码 -
res.type()：设置Content-Type的MIME类型
Route
var express = require('express');
var app = express();
// 主页输出 "Hello World"
app.get('/', function (req, res) {
console.log("主页 GET 请求");
res.send('Hello GET');
})
// POST 请求
app.post('/', function (req, res) {
console.log("主页 POST 请求");
res.send('Hello POST');
})
// /del_user 页面响应
app.get('/del_user', function (req, res) {
console.log("/del_user 响应 DELETE 请求");
res.send('删除页面');
})
// /list_user 页面 GET 请求
app.get('/list_user', function (req, res) {
console.log("/list_user GET 请求");
res.send('用户列表页面');
})
// 对页面 abcd, abxcd, ab123cd, 等响应 GET 请求
app.get('/ab*cd', function(req, res) {
console.log("/ab*cd GET 请求");
res.send('正则匹配');
})
var server = app.listen(8081, function () {
var host = server.address().address
var port = server.address().port
console.log("应用实例，访问地址为 http://%s:%s", host, port)
})
Static Files
We can export static files using express.static
app.use(express.static('public'));
and put some pics in public dir:
node_modules
server.js
public/
public/images
public/images/logo.png
Demo:
var express = require('express');
var app = express();
app.use(express.static('public'));
app.get('/', function (req, res) {
res.send('Hello World');
})
var server = app.listen(8081, function () {
var host = server.address().address
var port = server.address().port
console.log("应用实例，访问地址为 http://%s:%s", host, port)
})
now, we can visit pic using url: http://127.0.0.1:8081/images/logo.png
Get Method
index.html:
<html>
<body>
<form action="http://127.0.0.1:8081/process_get" method="GET">
First Name: <input type="text" name="first_name"> <br>
Last Name: <input type="text" name="last_name">
<input type="submit" value="Submit">
</form>
</body>
</html>
server.js:
var express = require('express');
var app = express();
app.use(express.static('public'));
app.get('/index.html', function (req, res) {
res.sendFile( __dirname + "/" + "index.html" );
})
app.get('/process_get', function (req, res) {
// 输出 JSON 格式
response = {
first_name:req.query.first_name,
last_name:req.query.last_name
};
console.log(response);
res.end(JSON.stringify(response));
})
var server = app.listen(8081, function () {
var host = server.address().address
var port = server.address().port
console.log("应用实例，访问地址为 http://%s:%s", host, port)
})
POST Method
index.html:
<html>
<body>
<form action="http://127.0.0.1:8081/process_post" method="POST">
First Name: <input type="text" name="first_name"> <br>
Last Name: <input type="text" name="last_name">
<input type="submit" value="Submit">
</form>
</body>
</html>
server.js
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
// 创建 application/x-www-form-urlencoded 编码解析
var urlencodedParser = bodyParser.urlencoded({ extended: false })
app.use(express.static('public'));
app.get('/index.html', function (req, res) {
res.sendFile( __dirname + "/" + "index.html" );
})
app.post('/process_post', urlencodedParser, function (req, res) {
// 输出 JSON 格式
response = {
first_name:req.body.first_name,
last_name:req.body.last_name
};
console.log(response);
res.end(JSON.stringify(response));
})
var server = app.listen(8081, function () {
var host = server.address().address
var port = server.address().port
console.log("应用实例，访问地址为 http://%s:%s", host, port)
})
File Upload
index.html
<html>
<head>
<title>文件上传表单</title>
</head>
<body>
<h3>文件上传：</h3>
选择一个文件上传: <br />
<form action="/file_upload" method="post" enctype="multipart/form-data">
<input type="file" name="image" size="50" />
<br />
<input type="submit" value="上传文件" />
</form>
</body>
</html>
server.js
var express = require('express');
var app = express();
var fs = require("fs");
var bodyParser = require('body-parser');
var multer = require('multer');
app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(multer({ dest: '/tmp/'}).array('image'));
app.get('/index.htm', function (req, res) {
res.sendFile( __dirname + "/" + "index.htm" );
})
app.post('/file_upload', function (req, res) {
console.log(req.files[0]); // 上传的文件信息
var des_file = __dirname + "/" + req.files[0].originalname;
fs.readFile( req.files[0].path, function (err, data) {
fs.writeFile(des_file, data, function (err) {
if( err ){
console.log( err );
}else{
response = {
message:'File uploaded successfully',
filename:req.files[0].originalname
};
}
console.log( response );
res.end( JSON.stringify( response ) );
});
});
})
var server = app.listen(8081, function () {
var host = server.address().address
var port = server.address().port
console.log("应用实例，访问地址为 http://%s:%s", host, port)
})
Cookie management
server.js
var express = require('express')
var cookieParser = require('cookie-parser')
var app = express()
app.use(cookieParser())
app.get('/', function(req, res) {
console.log("Cookies: ", req.cookies)
})
app.listen(8081)
