express 4.x API

express()

创建一个express应用. The express() 函数是一个顶级函数通过express模块导出的.

var express = require('express')
var app = express()

express 函数

express.json([options])

v4.16.0及更高版本中提供了此中间件

下表描述了可选的`options’对象的属性。

Property	Description	Type	Default
`inflate`	启用或禁用处理压缩的（压缩的）实体；禁用时，放气的身体将被拒绝	Boolean	`true`
`limit`	控制最大请求正文大小。如果这是一个数字，则该值指定字节数；如果是字符串，则将值传递到[bytes]库进行解析	Mixed	`"100kb"`
`reviver`	reviver选项被直接传递给JSON.parse作为第二个参数。您可以在有关JSON.parse的MDN文档中找到有关此参数的更多信息。	Function	`null`
`strict`	启用或禁用仅接受数组和对象；禁用时将接受`JSON.parse`接受的任何内容。	Boolean	`true`
`type`	这用于确定中间件将解析的媒体类型。此选项可以是字符串，字符串数组或函数。如果不是函数，则将type选项直接传递给[type-is]库，它可以是扩展名（例如json），MIME类型（例如application / json）或mime类型。带有通配符（例如`* / `或` / json`）。如果是函数，则将“类型”选项称为“ fn（req）”，如果请求返回真实值，则对该请求进行解析。	Mixed	`"application/json"`
`verify`	如果提供此选项，则称为“ verify（req，res，buf，encoding）”，其中“ buf”是原始请求主体的“ Buffer”，而“ encoding”是请求的编码。抛出错误可以中止解析。	Function	`undefined`

express.raw([options])

Express v4.17.0及更高版本中提供了此中间件。

下表描述了可选的`options’对象的属性。

Property	Description	Type	Default
`inflate`	启用或禁用处理压缩的（压缩的）实体；禁用时，放气的身体将被拒绝。	Boolean	`true`
`limit`	控制最大请求正文大小。如果这是一个数字，则该值指定字节数；如果是字符串，则将值传递到[bytes]库进行解析。	Mixed	`"100kb"`
`type`	这用于确定中间件将解析的媒体类型。此选项可以是字符串，字符串数组或函数。如果不是函数，则将`type`选项直接传递给[type-is]库，该库可以是扩展名（例如`bin ），哑剧类型（如“ application / octet-stream”）或带有通配符的哑剧类型（如“ * / ”或“ application / ”）。如果是函数，则将“类型”选项称为“ fn（req）”，如果请求返回真实值，则对该请求进行解析。 \| Mixed \|`"application/octet-stream"`
`verify`	如果提供此选项，则称为“ verify（req，res，buf，encoding）”，其中“ buf”是原始请求主体的“ Buffer”，而“ encoding”是请求的编码。抛出错误可以中止解析。	Function	`undefined`

express.Router([options])

创建一个新的router对象

var router = express.Router([options])

可选的“选项”参数指定路由器的行为。

Property	Description	Default	Availability
`caseSensitive`	Enable case sensitivity.启用区分大小写。	Disabled by default, treating “/Foo” and “/foo” as the same.
`mergeParams`	保留父路由器的`req.params`值。如果父母和孩子的参数名称冲突，则以孩子的值为准。	`false`	4.5.0+
`strict`	Enable strict routing.启用严格路由。	Disabled by default, “/foo” and “/foo/” are treated the same by the router.

express.static(root, [options])

下表描述了`options’对象的属性。另请参见以下示例。

Property	Description	Type	Default
`dotfiles`	确定如何处理点文件（以点“.”开头的文件或目录）。	String	“ignore”
`etag`	启用或禁用etag生成，注意：`express.static`总是发送弱ETag。	Boolean	`true`
`extensions`	设置文件扩展名后备：如果未找到文件，请搜索具有指定扩展名的文件并提供找到的第一个文件。例如：`['html'，'htm']`。	Mixed	`false`
`fallthrough`	让客户端错误作为未处理的请求进入，否则转发客户端错误。	Boolean	`true`
`immutable`	在“ Cache-Control”响应头中启用或禁用“ immutable”指令。如果启用，还应指定“ maxAge”选项以启用缓存。 `immutable`指令将阻止受支持的客户端在`maxAge`选项有效期内发出条件请求，以检查文件是否已更改。	Boolean	`false`
`index`	发送指定的目录索引文件。设置为false禁用目录索引。	Mixed	“index.html”
`lastModified`	将“ Last-Modified”标头设置为操作系统上文件的最后修改日期。	Boolean	`true`
`maxAge`	设置Cache-Control标头的max-age属性（以毫秒为单位）或以[ms]设置的字符串。	Number	0
`redirect`	当路径名是目录时，重定向到结尾的“ /”。	Boolean	`true`
`setHeaders`	设置HTTP标头以与文件一起使用的功能。	Function

dotfiles

Possible values for this option are:该选项的可能值为：

“allow” -对点文件没有特殊处理。
“deny” -拒绝对点文件的请求，以“ 403”响应，然后调用“ next（）”。
“ignore” - 就像点文件不存在一样，以“ 404”响应，然后调用“ next（）”。

NOTE: 使用默认值时，它将不会忽略以点开头的目录中的文件。

fallthrough

如果此选项为“ true”，则客户端错误（例如错误请求或对不存在文件的请求）将导致该中间件仅调用next（）来调用堆栈中的下一个中间件。如果为假，则这些错误（甚至是404错误）将调用“ next（err）”。

将此选项设置为“ true”，以便您可以将多个物理目录映射到同一网址，或用于路由以填充不存在的文件。

如果已将此中间件安装在严格设计为单个文件系统目录的路径上，请使用“ false”，这可以使404短路以减少开销。该中间件还将答复所有方法。

setHeaders

对于此选项，指定一个函数来设置自定义响应头。标头的更改必须同步进行。

该函数的签名是：

fn(res, path, stat)

Arguments:

res, the response object.
path,正在发送的文件路径。
stat, 发送文件的stat对象。

Example of express.static

这是将“ express.static”中间件功能与精心设计的options对象结合使用的示例：

var options = {dotfiles: 'ignore',etag: false,extensions: ['htm', 'html'],index: false,maxAge: '1d',redirect: false,setHeaders: function (res, path, stat) {res.set('x-timestamp', Date.now())}
}app.use(express.static('public', options))

express.text([options])

4.17.0开始启用.

Property	Description	Type	Default
`defaultCharset`	Specify the default character set for the text content if the charset is not specified in the `Content-Type` header of the request.	String	`"utf-8"`
`inflate`	Enables or disables handling deflated (compressed) bodies; when disabled, deflated bodies are rejected.	Boolean	`true`
`limit`	Controls the maximum request body size. If this is a number, then the value specifies the number of bytes; if it is a string, the value is passed to the bytes library for parsing.	Mixed	`"100kb"`
`type`	This is used to determine what media type the middleware will parse. This option can be a string, array of strings, or a function. If not a function, `type` option is passed directly to the type-is library and this can be an extension name (like `txt`), a mime type (like `text/plain`), or a mime type with a wildcard (like `/` or `text/*`). If a function, the `type` option is called as `fn(req)` and the request is parsed if it returns a truthy value.	Mixed	`"text/plain"`
`verify`	This option, if supplied, is called as `verify(req, res, buf, encoding)`, where `buf` is a `Buffer` of the raw request body and `encoding` is the encoding of the request. The parsing can be aborted by throwing an error.	Function	`undefined`

express.urlencoded([options])

v4.16.0 开始启用

Property	Description	Type	Default
`extended`	This option allows to choose between parsing the URL-encoded data with the `querystring` library (when `false`) or the `qs` library (when `true`). The “extended” syntax allows for rich objects and arrays to be encoded into the URL-encoded format, allowing for a JSON-like experience with URL-encoded. For more information, please see the qs library.	Boolean	`true`
`inflate`	Enables or disables handling deflated (compressed) bodies; when disabled, deflated bodies are rejected.	Boolean	`true`
`limit`	Controls the maximum request body size. If this is a number, then the value specifies the number of bytes; if it is a string, the value is passed to the bytes library for parsing.	Mixed	`"100kb"`
`parameterLimit`	This option controls the maximum number of parameters that are allowed in the URL-encoded data. If a request contains more parameters than this value, an error will be raised.	Number	`1000`
`type`	This is used to determine what media type the middleware will parse. This option can be a string, array of strings, or a function. If not a function, `type` option is passed directly to the type-is library and this can be an extension name (like `urlencoded`), a mime type (like `application/x-www-form-urlencoded`), or a mime type with a wildcard (like `*/x-www-form-urlencoded`). If a function, the `type` option is called as `fn(req)` and the request is parsed if it returns a truthy value.	Mixed	`"application/x-www-form-urlencoded"`
`verify`	This option, if supplied, is called as `verify(req, res, buf, encoding)`, where `buf` is a `Buffer` of the raw request body and `encoding` is the encoding of the request. The parsing can be aborted by throwing an error.	Function	`undefined`

Application

var express = require('express')
var app = express()app.get('/', function (req, res) {res.send('hello world')
})app.listen(3000)

app对象有以下函数：

Routing HTTP requests; see for example, app.METHOD and app.param.
Configuring middleware; see app.route.
Rendering HTML views; see app.render.
Registering a template engine; see app.engine.

app 属性

app.locals

app整个生命周期：

console.dir(app.locals.title)
// => 'My App'console.dir(app.locals.email)
// => 'me@myapp.com'

app.locals.title = 'My App'
app.locals.strftime = require('strftime')
app.locals.email = 'me@myapp.com'

app.mountpath

var express = require('express')var app = express() // the main app
var admin = express() // the sub appadmin.get('/', function (req, res) {console.log(admin.mountpath) // /adminres.send('Admin Homepage')
})app.use('/admin', admin) // mount the sub app

var admin = express()admin.get('/', function (req, res) {console.dir(admin.mountpath) // [ '/adm*n', '/manager' ]res.send('Admin Homepage')
})var secret = express()
secret.get('/', function (req, res) {console.log(secret.mountpath) // /secr*tres.send('Admin Secret')
})admin.use('/secr*t', secret) // load the 'secret' router on '/secr*t', on the 'admin' sub app
app.use(['/adm*n', '/manager'], admin) // load the 'admin' router on '/adm*n' and '/manager', on the parent app

Events

app.on(‘mount’, callback(parent))

var admin = express()admin.on('mount', function (parent) {console.log('Admin Mounted')console.log(parent) // refers to the parent app
})admin.get('/', function (req, res) {res.send('Admin Homepage')
})app.use('/admin', admin)

app 函数

app.all(path, callback [, callback …])

app.all('/secret', function (req, res, next) {console.log('Accessing the secret section ...')next() // pass control to the next handler
})

app.all('*', requireAuthentication, loadUser)

app.all('*', requireAuthentication)
app.all('*', loadUser)

app.all('/api/*', requireAuthentication)

app.delete(path, callback [, callback …])

app.delete('/', function (req, res) {res.send('DELETE request to homepage')
})

app.disable(name)

app.disable('trust proxy')
app.get('trust proxy')
// => false

app.disabled(name)

app.disabled('trust proxy')
// => trueapp.enable('trust proxy')
app.disabled('trust proxy')
// => false

app.enable(name)

app.enable('trust proxy')
app.get('trust proxy')
// => true

app.enabled(name)

app.enabled('trust proxy')
// => falseapp.enable('trust proxy')
app.enabled('trust proxy')
// => true

app.engine(ext, callback)

app.engine('pug', require('pug').__express)

app.engine('html', require('ejs').renderFile)

var engines = require('consolidate')
app.engine('haml', engines.haml)
app.engine('html', engines.hogan)

app.get(name)

app.get('title')
// => undefinedapp.set('title', 'My Site')
app.get('title')
// => "My Site"

app.get(path, callback [, callback …])

app.get('/', function (req, res) {res.send('GET request to homepage')
})

app.listen(path, [callback])

var express = require('express')
var app = express()
app.listen('/tmp/sock')

app.listen([port[, host[, backlog]]][, callback])

var express = require('express')
var app = express()
app.listen(3000)

var express = require('express')
var https = require('https')
var http = require('http')
var app = express()http.createServer(app).listen(80)
https.createServer(options, app).listen(443)

app.listen = function () {var server = http.createServer(this)return server.listen.apply(server, arguments)
}

app.METHOD(path, callback [, callback …])

app.param([name], callback)

app.param('user', function (req, res, next, id) {// try to get the user details from the User model and attach it to the request objectUser.find(id, function (err, user) {if (err) {next(err)} else if (user) {req.user = usernext()} else {next(new Error('failed to load user'))}})
})

app.param('id', function (req, res, next, id) {console.log('CALLED ONLY ONCE')next()
})app.get('/user/:id', function (req, res, next) {console.log('although this matches')next()
})app.get('/user/:id', function (req, res) {console.log('and this matches too')res.end()
})

app.get('/user/:id/:page', function (req, res) {console.log('and this matches too')res.end()
})

var express = require('express')
var app = express()// customizing the behavior of app.param()
app.param(function (param, option) {return function (req, res, next, val) {if (val === option) {next()} else {next('route')}}
})// using the customized app.param()
app.param('id', 1337)// route to trigger the capture
app.get('/user/:id', function (req, res) {res.send('OK')
})app.listen(3000, function () {console.log('Ready')
})

app.param(function (param, validator) {return function (req, res, next, val) {if (validator(val)) {next()} else {next('route')}}
})app.param('id', function (candidate) {return !isNaN(parseFloat(candidate)) && isFinite(candidate)
})

Examples:

//captures '1-a_6' but not '543-azser-sder'
router.get('/[0-9]+-[[\\w]]*', function);//captures '1-a_6' and '543-az(ser"-sder' but not '5-a s'
router.get('/[0-9]+-[[\\S]]*', function);//captures all (equivalent to '.*')
router.get('[[\\s\\S]]*', function);

app.path()

var app = express()
var blog = express()
var blogAdmin = express()app.use('/blog', blog)
blog.use('/admin', blogAdmin)console.dir(app.path()) // ''
console.dir(blog.path()) // '/blog'
console.dir(blogAdmin.path()) // '/blog/admin'

app.render(view, [locals], callback)

app.render('email', function (err, html) {// ...
})app.render('email', { name: 'Tobi' }, function (err, html) {// ...
})

app.route(path)

var app = express()app.route('/events').all(function (req, res, next) {// runs for all HTTP verbs first// think of it as route specific middleware!}).get(function (req, res, next) {res.json({})}).post(function (req, res, next) {// maybe add a new event...})

app.set(name, value)

app.set('title', 'My Site')
app.get('title') // "My Site"

app.use([path,] callback [, callback…])

path不传默认为"/"

app.use(function (req, res, next) {console.log('Time: %d', Date.now())next()
})

// this middleware will not allow the request to go beyond it
app.use(function (req, res, next) {res.send('Hello World')
})// requests will never reach this route
app.get('/', function (req, res) {res.send('Welcome')
})

app.use(function (err, req, res, next) {console.error(err.stack)res.status(500).send('Something broke!')
})

// GET /style.css etc
app.use(express.static(path.join(__dirname, 'public')))

// GET /static/style.css etc.
app.use('/static', express.static(path.join(__dirname, 'public')))

app.use(express.static(path.join(__dirname, 'public')))
app.use(logger())

app.use(express.static(path.join(__dirname, 'public')))
app.use(express.static(path.join(__dirname, 'files')))
app.use(express.static(path.join(__dirname, 'uploads')))

Request

app.get('/user/:id', function (req, res) {res.send('user ' + req.params.id)
})

app.get('/user/:id', function (request, response) {response.send('user ' + request.params.id)
})

Properties

在Express 4中，默认情况下，“ req.files”在“ req”对象上不再可用。要访问“ req.files”对象上的上传文件，请使用多部分处理中间件，例如 busboy, multer, formidable, multiparty, connect-multiparty, or pez.

req.app

// index.js
app.get('/viewdirectory', require('./mymiddleware.js'))
// mymiddleware.js
module.exports = function (req, res) {res.send('The views directory is ' + req.app.get('views'))
}

req.baseUrl

var greet = express.Router()greet.get('/jp', function (req, res) {console.log(req.baseUrl) // /greetres.send('Konichiwa!')
})app.use('/greet', greet) // load the router on '/greet'

app.use(['/gre+t', '/hel{2}o'], greet) // load the router on '/gre+t' and '/hel{2}o'

req.body

var express = require('express')var app = express()app.use(express.json()) // for parsing application/json
app.use(express.urlencoded({ extended: true })) // for parsing application/x-www-form-urlencodedapp.post('/profile', function (req, res, next) {console.log(req.body)res.json(req.body)
})

req.cookies

// Cookie: name=tj
console.dir(req.cookies.name)
// => 'tj'

req.fresh

console.dir(req.fresh)
// => true

req.hostname

// Host: "example.com:3000"
console.dir(req.hostname)
// => 'example.com'

req.ip

console.dir(req.ip)
// => '127.0.0.1'

req.ips

req.method

req.originalUrl

// GET /search?q=something
console.dir(req.originalUrl)
// => '/search?q=something'

app.use('/admin', function (req, res, next) { // GET 'http://www.example.com/admin/new'console.dir(req.originalUrl) // '/admin/new'console.dir(req.baseUrl) // '/admin'console.dir(req.path) // '/new'next()
})

req.params

// GET /user/tj
console.dir(req.params.name)
// => 'tj'

// GET /file/javascripts/jquery.js
console.dir(req.params[0])
// => 'javascripts/jquery.js'

req.path

// example.com/users?sort=desc
console.dir(req.path)
// => '/users'

req.protocol

console.dir(req.protocol)
// => 'http'

req.query

// GET /search?q=tobi+ferret
console.dir(req.query.q)
// => 'tobi ferret'// GET /shoes?order=desc&shoe[color]=blue&shoe[type]=converse
console.dir(req.query.order)
// => 'desc'console.dir(req.query.shoe.color)
// => 'blue'console.dir(req.query.shoe.type)
// => 'converse'// GET /shoes?color[]=blue&color[]=black&color[]=red
console.dir(req.query.color)
// => ['blue', 'black', 'red']

req.route

app.get('/user/:id?', function userIdHandler (req, res) {console.log(req.route)res.send('GET')
})

{ path: '/user/:id?',stack:[ { handle: [Function: userIdHandler],name: 'userIdHandler',params: undefined,path: undefined,keys: [],regexp: /^\/?$/i,method: 'get' } ],methods: { get: true } }

req.secure

console.dir(req.protocol === 'https')
// => true

req.signedCookies

// Cookie: user=tobi.CP7AWaXDfAKIRfH49dQzKJx7sKzzSoPq7/AcBBRVwlI3
console.dir(req.signedCookies.user)
// => 'tobi'

req.stale

console.dir(req.stale)
// => true

req.subdomains

// Host: "tobi.ferrets.example.com"
console.dir(req.subdomains)
// => ['ferrets', 'tobi']

req.xhr

console.dir(req.xhr)
// => true

Methods

req.accepts(types)

// Accept: text/html
req.accepts('html')
// => "html"// Accept: text/*, application/json
req.accepts('html')
// => "html"
req.accepts('text/html')
// => "text/html"
req.accepts(['json', 'text'])
// => "json"
req.accepts('application/json')
// => "application/json"// Accept: text/*, application/json
req.accepts('image/png')
req.accepts('png')
// => false// Accept: text/*;q=.5, application/json
req.accepts(['html', 'json'])
// => "json"

req.acceptsCharsets(charset [, …])

req.acceptsEncodings(encoding [, …])

req.acceptsLanguages(lang [, …])

req.get(field)

req.get('Content-Type')
// => "text/plain"req.get('content-type')
// => "text/plain"req.get('Something')
// => undefined

req.is(type)

// With Content-Type: text/html; charset=utf-8
req.is('html')
// => 'html'
req.is('text/html')
// => 'text/html'
req.is('text/*')
// => 'text/*'// When Content-Type is application/json
req.is('json')
// => 'json'
req.is('application/json')
// => 'application/json'
req.is('application/*')
// => 'application/*'req.is('html')
// => false

req.param(name [, defaultValue])

// ?name=tobi
req.param('name')
// => "tobi"// POST name=tobi
req.param('name')
// => "tobi"// /user/tobi for /user/:name
req.param('name')
// => "tobi"

req.range(size[, options])

// parse header from request
var range = req.range(1000)// the type of the range
if (range.type === 'bytes') {// the rangesrange.forEach(function (r) {// do something with r.start and r.end})
}

Response

For example:

app.get('/user/:id', function (req, res) {res.send('user ' + req.params.id)
})

But you could just as well have:

app.get('/user/:id', function (request, response) {response.send('user ' + request.params.id)
})

Response属性

res.app

res.headersSent

app.get('/', function (req, res) {console.dir(res.headersSent) // falseres.send('OK')console.dir(res.headersSent) // true
})

res.locals

app.use(function (req, res, next) {res.locals.user = req.userres.locals.authenticated = !req.user.anonymousnext()
})

Response函数

res.append(field [, value])

res.append('Link', ['<http://localhost/>', '<http://localhost:3000/>'])
res.append('Set-Cookie', 'foo=bar; Path=/; HttpOnly')
res.append('Warning', '199 Miscellaneous warning')

res.attachment([filename])

res.attachment()
// Content-Disposition: attachmentres.attachment('path/to/logo.png')
// Content-Disposition: attachment; filename="logo.png"
// Content-Type: image/png

res.cookie(name, value [, options])

Property	Type	Description
`domain`	String	Domain name for the cookie. Defaults to the domain name of the app.
`encode`	Function	A synchronous function used for cookie value encoding. Defaults to `encodeURIComponent`.
`expires`	Date	Expiry date of the cookie in GMT. If not specified or set to 0, creates a session cookie.
`httpOnly`	Boolean	Flags the cookie to be accessible only by the web server.
`maxAge`	Number	Convenient option for setting the expiry time relative to the current time in milliseconds.
`path`	String	Path for the cookie. Defaults to “/”.
`secure`	Boolean	Marks the cookie to be used with HTTPS only.
`signed`	Boolean	Indicates if the cookie should be signed.
`sameSite`	Boolean or String	Value of the “SameSite” Set-Cookie attribute. More information at https://tools.ietf.org/html/draft-ietf-httpbis-cookie-same-site-00#section-4.1.1.

res.cookie('name', 'tobi', { domain: '.example.com', path: '/admin', secure: true })
res.cookie('rememberme', '1', { expires: new Date(Date.now() + 900000), httpOnly: true })

res.status(201).cookie('access_token', 'Bearer ' + token, {expires: new Date(Date.now() + 8 * 3600000) // cookie will be removed after 8 hours}).cookie('test', 'test').redirect(301, '/admin')

// Default encoding
res.cookie('some_cross_domain_cookie', 'http://mysubdomain.example.com', { domain: 'example.com' })
// Result: 'some_cross_domain_cookie=http%3A%2F%2Fmysubdomain.example.com; Domain=example.com; Path=/'// Custom encoding
res.cookie('some_cross_domain_cookie', 'http://mysubdomain.example.com', { domain: 'example.com', encode: String })
// Result: 'some_cross_domain_cookie=http://mysubdomain.example.com; Domain=example.com; Path=/;'

res.cookie('rememberme', '1', { maxAge: 900000, httpOnly: true })

res.cookie('cart', { items: [1, 2, 3] })
res.cookie('cart', { items: [1, 2, 3] }, { maxAge: 900000 })

res.cookie('name', 'tobi', { signed: true })

res.clearCookie(name [, options])

res.cookie('name', 'tobi', { path: '/admin' })
res.clearCookie('name', { path: '/admin' })

res.download(path [, filename] [, options] [, fn])

res.download('/report-12345.pdf')res.download('/report-12345.pdf', 'report.pdf')res.download('/report-12345.pdf', 'report.pdf', function (err) {if (err) {// Handle error, but keep in mind the response may be partially-sent// so check res.headersSent} else {// decrement a download credit, etc.}
})

res.end([data] [, encoding])

res.end()
res.status(404).end()

res.format(object)

res.format({'text/plain': function () {res.send('hey')},'text/html': function () {res.send('<p>hey</p>')},'application/json': function () {res.send({ message: 'hey' })},default: function () {// log the request and respond with 406res.status(406).send('Not Acceptable')}
})

res.format({text: function () {res.send('hey')},html: function () {res.send('<p>hey</p>')},json: function () {res.send({ message: 'hey' })}
})

res.get(field)

res.get('Content-Type')
// => "text/plain"

res.json([body])

res.json(null)
res.json({ user: 'tobi' })
res.status(500).json({ error: 'message' })

res.jsonp([body])

res.jsonp(null)
// => callback(null)res.jsonp({ user: 'tobi' })
// => callback({ "user": "tobi" })res.status(500).jsonp({ error: 'message' })
// => callback({ "error": "message" })

// ?callback=foo
res.jsonp({ user: 'tobi' })
// => foo({ "user": "tobi" })app.set('jsonp callback name', 'cb')// ?cb=foo
res.status(500).jsonp({ error: 'message' })
// => foo({ "error": "message" })

res.links(links)

res.links({next: 'http://api.example.com/users?page=2',last: 'http://api.example.com/users?page=5'
})

Link: <http://api.example.com/users?page=2>; rel="next",<http://api.example.com/users?page=5>; rel="last"

res.location(path)

res.location('/foo/bar')
res.location('http://example.com')
res.location('back')

res.redirect([status,] path)

res.redirect('/foo/bar')
res.redirect('http://example.com')
res.redirect(301, 'http://example.com')
res.redirect('../login')

res.redirect('http://google.com')

res.redirect('/admin')

res.redirect('post/new')

res.redirect('..')

res.redirect('back')

res.render(view [, locals] [, callback])

// send the rendered view to the client
res.render('index')// if a callback is specified, the rendered HTML string has to be sent explicitly
res.render('index', function (err, html) {res.send(html)
})// pass a local variable to the view
res.render('user', { name: 'Tobi' }, function (err, html) {// ...
})

res.send([body])

res.send(Buffer.from('whoop'))
res.send({ some: 'json' })
res.send('<p>some html</p>')
res.status(404).send('Sorry, we cannot find that!')
res.status(500).send({ error: 'something blew up' })

res.set('Content-Type', 'text/html')
res.send(Buffer.from('<p>some html</p>'))

res.send('<p>some html</p>')

res.send({ user: 'tobi' })
res.send([1, 2, 3])

res.sendFile(path [, options] [, fn])

Property	Description	Default	Availability
`maxAge`	Sets the max-age property of the `Cache-Control` header in milliseconds or a string in ms format	0
`root`	Root directory for relative filenames.
`lastModified`	Sets the `Last-Modified` header to the last modified date of the file on the OS. Set `false` to disable it.	Enabled	4.9.0+
`headers`	Object containing HTTP headers to serve with the file.
`dotfiles`	Option for serving dotfiles. Possible values are “allow”, “deny”, “ignore”.	“ignore”
`acceptRanges`	Enable or disable accepting ranged requests.	`true`	4.14+
`cacheControl`	Enable or disable setting `Cache-Control` response header.	`true`	4.14+
`immutable`	Enable or disable the `immutable` directive in the `Cache-Control` response header. If enabled, the `maxAge` option should also be specified to enable caching. The `immutable` directive will prevent supported clients from making conditional requests during the life of the `maxAge` option to check if the file has changed.	`false`	4.16+

app.get('/file/:name', function (req, res, next) {var options = {root: path.join(__dirname, 'public'),dotfiles: 'deny',headers: {'x-timestamp': Date.now(),'x-sent': true}}var fileName = req.params.nameres.sendFile(fileName, options, function (err) {if (err) {next(err)} else {console.log('Sent:', fileName)}})
})

app.get('/user/:uid/photos/:file', function (req, res) {var uid = req.params.uidvar file = req.params.filereq.user.mayViewFilesFrom(uid, function (yes) {if (yes) {res.sendFile('/uploads/' + uid + '/' + file)} else {res.status(403).send("Sorry! You can't see that.")}})
})

res.sendStatus(statusCode)

res.sendStatus(200) // equivalent to res.status(200).send('OK')
res.sendStatus(403) // equivalent to res.status(403).send('Forbidden')
res.sendStatus(404) // equivalent to res.status(404).send('Not Found')
res.sendStatus(500) // equivalent to res.status(500).send('Internal Server Error')

res.sendStatus(9999) // equivalent to res.status(9999).send('9999')

res.set(field [, value])

res.set('Content-Type', 'text/plain')res.set({'Content-Type': 'text/plain','Content-Length': '123',ETag: '12345'
})

res.status(code)

res.status(403).end()
res.status(400).send('Bad Request')
res.status(404).sendFile('/absolute/path/to/404.png')

res.type(type)

res.type('.html')
// => 'text/html'
res.type('html')
// => 'text/html'
res.type('json')
// => 'application/json'
res.type('application/json')
// => 'application/json'
res.type('png')
// => 'image/png'

res.vary(field)

res.vary('User-Agent').render('docs')

Router（路由）

express有一个Router()函数，创建一个新的router对象

var router = express.Router()
// invoked for any requests passed to this router
router.use(function (req, res, next) {// .. some logic here .. like any other middlewarenext()
})// will handle any request that ends in /events
// depends on where the router is "use()'d"
router.get('/events', function (req, res, next) {// ..
})

// only requests to /calendar/* will be sent to our "router"
app.use('/calendar', router)

Router函数

router.all(path, [callback, …] callback)

router.all('*', requireAuthentication, loadUser)

router.all('*', requireAuthentication)
router.all('*', loadUser)

router.all('/api/*', requireAuthentication)

router.METHOD(path, [callback, …] callback)

router.get('/', function (req, res) {res.send('hello world')
})

router.get(/^\/commits\/(\w+)(?:\.\.(\w+))?$/, function (req, res) {var from = req.params[0]var to = req.params[1] || 'HEAD'res.send('commit range ' + from + '..' + to)
})

router.param(name, callback)

router.param('user', function (req, res, next, id) {// try to get the user details from the User model and attach it to the request objectUser.find(id, function (err, user) {if (err) {next(err)} else if (user) {req.user = usernext()} else {next(new Error('failed to load user'))}})
})

router.param('id', function (req, res, next, id) {console.log('CALLED ONLY ONCE')next()
})router.get('/user/:id', function (req, res, next) {console.log('although this matches')next()
})router.get('/user/:id', function (req, res) {console.log('and this matches too')res.end()
})

On GET /user/42, the following is printed:

CALLED ONLY ONCE
although this matches
and this matches too

var express = require('express')
var app = express()
var router = express.Router()// customizing the behavior of router.param()
router.param(function (param, option) {return function (req, res, next, val) {if (val === option) {next()} else {res.sendStatus(403)}}
})// using the customized router.param()
router.param('id', '1337')// route to trigger the capture
router.get('/user/:id', function (req, res) {res.send('OK')
})app.use(router)app.listen(3000, function () {console.log('Ready')
})

router.param(function (param, validator) {return function (req, res, next, val) {if (validator(val)) {next()} else {res.sendStatus(403)}}
})router.param('id', function (candidate) {return !isNaN(parseFloat(candidate)) && isFinite(candidate)
})

router.route(path)

var router = express.Router()router.param('user_id', function (req, res, next, id) {// sample user, would actually fetch from DB, etc...req.user = {id: id,name: 'TJ'}next()
})router.route('/users/:user_id').all(function (req, res, next) {// runs for all HTTP verbs first// think of it as route specific middleware!next()}).get(function (req, res, next) {res.json(req.user)}).put(function (req, res, next) {// just an example of maybe updating the userreq.user.name = req.params.name// save user ... etcres.json(req.user)}).post(function (req, res, next) {next(new Error('not implemented'))}).delete(function (req, res, next) {next(new Error('not implemented'))})

var express = require('express')
var app = express()
var router = express.Router()// simple logger for this router's requests
// all requests to this router will first hit this middleware
router.use(function (req, res, next) {console.log('%s %s %s', req.method, req.url, req.path)next()
})// this will only be invoked if the path starts with /bar from the mount point
router.use('/bar', function (req, res, next) {// ... maybe some additional /bar logging ...next()
})// always invoked
router.use(function (req, res, next) {res.send('Hello World')
})app.use('/foo', router)app.listen(3000)

var logger = require('morgan')
var path = require('path')router.use(logger())
router.use(express.static(path.join(__dirname, 'public')))
router.use(function (req, res) {res.send('Hello')
})

router.use(express.static(path.join(__dirname, 'public')))
router.use(logger())
router.use(function (req, res) {res.send('Hello')
})

router.use(express.static(path.join(__dirname, 'public')))
router.use(express.static(path.join(__dirname, 'files')))
router.use(express.static(path.join(__dirname, 'uploads')))

var authRouter = express.Router()
var openRouter = express.Router()authRouter.use(require('./authenticate').basic(usersdb))authRouter.get('/:user_id/edit', function (req, res, next) {// ... Edit user UI ...
})
openRouter.get('/', function (req, res, next) {// ... List users ...
})
openRouter.get('/:user_id', function (req, res, next) {// ... View user ...
})app.use('/users', authRouter)
app.use('/users', openRouter)

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