lib/response.js
/*!
* express
* Copyright(c) 2009-2013 TJ Holowaychuk
* Copyright(c) 2014-2015 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict';
/**
* Module dependencies.
* @private
*/
var Buffer = require('node:buffer').Buffer
var contentDisposition = require('content-disposition');
var createError = require('http-errors')
var encodeUrl = require('encodeurl');
var escapeHtml = require('escape-html');
var http = require('http');
var onFinished = require('on-finished');
var mime = require('mime-types')
var path = require('path');
var pathIsAbsolute = require('path').isAbsolute;
var statuses = require('statuses')
var merge = require('utils-merge');
var sign = require('cookie-signature').sign;
var normalizeType = require('./utils').normalizeType;
var normalizeTypes = require('./utils').normalizeTypes;
var setCharset = require('./utils').setCharset;
var cookie = require('cookie');
var send = require('send');
var extname = path.extname;
var resolve = path.resolve;
var vary = require('vary');
/**
* Response prototype.
* @public
*/
var res = Object.create(http.ServerResponse.prototype)
/**
* Module exports.
* @public
*/
module.exports = res
/**
* Set the HTTP status code for the response.
*
* Expects an integer value between 100 and 999 inclusive.
* Throws an error if the provided status code is not an integer or if it's outside the allowable range.
*
* @param {number} code - The HTTP status code to set.
* @return {ServerResponse} - Returns itself for chaining methods.
* @throws {TypeError} If `code` is not an integer.
* @throws {RangeError} If `code` is outside the range 100 to 999.
* @public
*/
res.status = function status(code) {
// Check if the status code is not an integer
if (!Number.isInteger(code)) {
throw new TypeError(`Invalid status code: ${JSON.stringify(code)}. Status code must be an integer.`);
}
// Check if the status code is outside of Node's valid range
if (code < 100 || code > 999) {
throw new RangeError(`Invalid status code: ${JSON.stringify(code)}. Status code must be greater than 99 and less than 1000.`);
}
this.statusCode = code;
return this;
};
/**
* Set Link header field with the given `links`.
*
* Examples:
*
* res.links({
* next: 'http://api.example.com/users?page=2',
* last: 'http://api.example.com/users?page=5'
* });
*
* @param {Object} links
* @return {ServerResponse}
* @public
*/
res.links = function(links){
var link = this.get('Link') || '';
if (link) link += ', ';
return this.set('Link', link + Object.keys(links).map(function(rel){
return '<' + links[rel] + '>; rel="' + rel + '"';
}).join(', '));
};
/**
* Send a response.
*
* Examples:
*
* res.send(Buffer.from('wahoo'));
* res.send({ some: 'json' });
* res.send('<p>some html</p>');
*
* @param {string|number|boolean|object|Buffer} body
* @public
*/
res.send = function send(body) {
var chunk = body;
var encoding;
var req = this.req;
var type;
// settings
var app = this.app;
switch (typeof chunk) {
// string defaulting to html
case 'string':
if (!this.get('Content-Type')) {
this.type('html');
}
break;
case 'boolean':
case 'number':
case 'object':
if (chunk === null) {
chunk = '';
} else if (Buffer.isBuffer(chunk)) {
if (!this.get('Content-Type')) {
this.type('bin');
}
} else {
return this.json(chunk);
}
break;
}
// write strings in utf-8
if (typeof chunk === 'string') {
encoding = 'utf8';
type = this.get('Content-Type');
// reflect this in content-type
if (typeof type === 'string') {
this.set('Content-Type', setCharset(type, 'utf-8'));
}
}
// determine if ETag should be generated
var etagFn = app.get('etag fn')
var generateETag = !this.get('ETag') && typeof etagFn === 'function'
// populate Content-Length
var len
if (chunk !== undefined) {
if (Buffer.isBuffer(chunk)) {
// get length of Buffer
len = chunk.length
} else if (!generateETag && chunk.length < 1000) {
// just calculate length when no ETag + small chunk
len = Buffer.byteLength(chunk, encoding)
} else {
// convert chunk to Buffer and calculate
chunk = Buffer.from(chunk, encoding)
encoding = undefined;
len = chunk.length
}
this.set('Content-Length', len);
}
// populate ETag
var etag;
if (generateETag && len !== undefined) {
if ((etag = etagFn(chunk, encoding))) {
this.set('ETag', etag);
}
}
// freshness
if (req.fresh) this.status(304);
// strip irrelevant headers
if (204 === this.statusCode || 304 === this.statusCode) {
this.removeHeader('Content-Type');
this.removeHeader('Content-Length');
this.removeHeader('Transfer-Encoding');
chunk = '';
}
// alter headers for 205
if (this.statusCode === 205) {
this.set('Content-Length', '0')
this.removeHeader('Transfer-Encoding')
chunk = ''
}
if (req.method === 'HEAD') {
// skip body for HEAD
this.end();
} else {
// respond
this.end(chunk, encoding);
}
return this;
};
/**
* Send JSON response.
*
* Examples:
*
* res.json(null);
* res.json({ user: 'tj' });
*
* @param {string|number|boolean|object} obj
* @public
*/
res.json = function json(obj) {
// settings
var app = this.app;
var escape = app.get('json escape')
var replacer = app.get('json replacer');
var spaces = app.get('json spaces');
var body = stringify(obj, replacer, spaces, escape)
// content-type
if (!this.get('Content-Type')) {
this.set('Content-Type', 'application/json');
}
return this.send(body);
};
/**
* Send JSON response with JSONP callback support.
*
* Examples:
*
* res.jsonp(null);
* res.jsonp({ user: 'tj' });
*
* @param {string|number|boolean|object} obj
* @public
*/
res.jsonp = function jsonp(obj) {
// settings
var app = this.app;
var escape = app.get('json escape')
var replacer = app.get('json replacer');
var spaces = app.get('json spaces');
var body = stringify(obj, replacer, spaces, escape)
var callback = this.req.query[app.get('jsonp callback name')];
// content-type
if (!this.get('Content-Type')) {
this.set('X-Content-Type-Options', 'nosniff');
this.set('Content-Type', 'application/json');
}
// fixup callback
if (Array.isArray(callback)) {
callback = callback[0];
}
// jsonp
if (typeof callback === 'string' && callback.length !== 0) {
this.set('X-Content-Type-Options', 'nosniff');
this.set('Content-Type', 'text/javascript');
// restrict callback charset
callback = callback.replace(/[^\[\]\w$.]/g, '');
if (body === undefined) {
// empty argument
body = ''
} else if (typeof body === 'string') {
// replace chars not allowed in JavaScript that are in JSON
body = body
.replace(/\u2028/g, '\\u2028')
.replace(/\u2029/g, '\\u2029')
}
// the /**/ is a specific security mitigation for "Rosetta Flash JSONP abuse"
// the typeof check is just to reduce client error noise
body = '/**/ typeof ' + callback + ' === \'function\' && ' + callback + '(' + body + ');';
}
return this.send(body);
};
/**
* Send given HTTP status code.
*
* Sets the response status to `statusCode` and the body of the
* response to the standard description from node's http.STATUS_CODES
* or the statusCode number if no description.
*
* Examples:
*
* res.sendStatus(200);
*
* @param {number} statusCode
* @public
*/
res.sendStatus = function sendStatus(statusCode) {
var body = statuses.message[statusCode] || String(statusCode)
this.status(statusCode);
this.type('txt');
return this.send(body);
};
/**
* Transfer the file at the given `path`.
*
* Automatically sets the _Content-Type_ response header field.
* The callback `callback(err)` is invoked when the transfer is complete
* or when an error occurs. Be sure to check `res.headersSent`
* if you wish to attempt responding, as the header and some data
* may have already been transferred.
*
* Options:
*
* - `maxAge` defaulting to 0 (can be string converted by `ms`)
* - `root` root directory for relative filenames
* - `headers` object of headers to serve with file
* - `dotfiles` serve dotfiles, defaulting to false; can be `"allow"` to send them
*
* Other options are passed along to `send`.
*
* Examples:
*
* The following example illustrates how `res.sendFile()` may
* be used as an alternative for the `static()` middleware for
* dynamic situations. The code backing `res.sendFile()` is actually
* the same code, so HTTP cache support etc is identical.
*
* app.get('/user/:uid/photos/:file', function(req, res){
* var uid = req.params.uid
* , file = req.params.file;
*
* req.user.mayViewFilesFrom(uid, function(yes){
* if (yes) {
* res.sendFile('/uploads/' + uid + '/' + file);
* } else {
* res.send(403, 'Sorry! you cant see that.');
* }
* });
* });
*
* @public
*/
res.sendFile = function sendFile(path, options, callback) {
var done = callback;
var req = this.req;
var res = this;
var next = req.next;
var opts = options || {};
if (!path) {
throw new TypeError('path argument is required to res.sendFile');
}
if (typeof path !== 'string') {
throw new TypeError('path must be a string to res.sendFile')
}
// support function as second arg
if (typeof options === 'function') {
done = options;
opts = {};
}
if (!opts.root && !pathIsAbsolute(path)) {
throw new TypeError('path must be absolute or specify root to res.sendFile');
}
// create file stream
var pathname = encodeURI(path);
var file = send(req, pathname, opts);
// transfer
sendfile(res, file, opts, function (err) {
if (done) return done(err);
if (err && err.code === 'EISDIR') return next();
// next() all but write errors
if (err && err.code !== 'ECONNABORTED' && err.syscall !== 'write') {
next(err);
}
});
};
/**
* Transfer the file at the given `path` as an attachment.
*
* Optionally providing an alternate attachment `filename`,
* and optional callback `callback(err)`. The callback is invoked
* when the data transfer is complete, or when an error has
* occurred. Be sure to check `res.headersSent` if you plan to respond.
*
* Optionally providing an `options` object to use with `res.sendFile()`.
* This function will set the `Content-Disposition` header, overriding
* any `Content-Disposition` header passed as header options in order
* to set the attachment and filename.
*
* This method uses `res.sendFile()`.
*
* @public
*/
res.download = function download (path, filename, options, callback) {
var done = callback;
var name = filename;
var opts = options || null
// support function as second or third arg
if (typeof filename === 'function') {
done = filename;
name = null;
opts = null
} else if (typeof options === 'function') {
done = options
opts = null
}
// support optional filename, where options may be in it's place
if (typeof filename === 'object' &&
(typeof options === 'function' || options === undefined)) {
name = null
opts = filename
}
// set Content-Disposition when file is sent
var headers = {
'Content-Disposition': contentDisposition(name || path)
};
// merge user-provided headers
if (opts && opts.headers) {
var keys = Object.keys(opts.headers)
for (var i = 0; i < keys.length; i++) {
var key = keys[i]
if (key.toLowerCase() !== 'content-disposition') {
headers[key] = opts.headers[key]
}
}
}
// merge user-provided options
opts = Object.create(opts)
opts.headers = headers
// Resolve the full path for sendFile
var fullPath = !opts.root
? resolve(path)
: path
// send file
return this.sendFile(fullPath, opts, done)
};
/**
* Set _Content-Type_ response header with `type` through `mime.contentType()`
* when it does not contain "/", or set the Content-Type to `type` otherwise.
* When no mapping is found though `mime.contentType()`, the type is set to
* "application/octet-stream".
*
* Examples:
*
* res.type('.html');
* res.type('html');
* res.type('json');
* res.type('application/json');
* res.type('png');
*
* @param {String} type
* @return {ServerResponse} for chaining
* @public
*/
res.contentType =
res.type = function contentType(type) {
var ct = type.indexOf('/') === -1
? (mime.contentType(type) || 'application/octet-stream')
: type;
return this.set('Content-Type', ct);
};
/**
* Respond to the Acceptable formats using an `obj`
* of mime-type callbacks.
*
* This method uses `req.accepted`, an array of
* acceptable types ordered by their quality values.
* When "Accept" is not present the _first_ callback
* is invoked, otherwise the first match is used. When
* no match is performed the server responds with
* 406 "Not Acceptable".
*
* Content-Type is set for you, however if you choose
* you may alter this within the callback using `res.type()`
* or `res.set('Content-Type', ...)`.
*
* res.format({
* 'text/plain': function(){
* res.send('hey');
* },
*
* 'text/html': function(){
* res.send('<p>hey</p>');
* },
*
* 'application/json': function () {
* res.send({ message: 'hey' });
* }
* });
*
* In addition to canonicalized MIME types you may
* also use extnames mapped to these types:
*
* res.format({
* text: function(){
* res.send('hey');
* },
*
* html: function(){
* res.send('<p>hey</p>');
* },
*
* json: function(){
* res.send({ message: 'hey' });
* }
* });
*
* By default Express passes an `Error`
* with a `.status` of 406 to `next(err)`
* if a match is not made. If you provide
* a `.default` callback it will be invoked
* instead.
*
* @param {Object} obj
* @return {ServerResponse} for chaining
* @public
*/
res.format = function(obj){
var req = this.req;
var next = req.next;
var keys = Object.keys(obj)
.filter(function (v) { return v !== 'default' })
var key = keys.length > 0
? req.accepts(keys)
: false;
this.vary("Accept");
if (key) {
this.set('Content-Type', normalizeType(key).value);
obj[key](req, this, next);
} else if (obj.default) {
obj.default(req, this, next)
} else {
next(createError(406, {
types: normalizeTypes(keys).map(function (o) { return o.value })
}))
}
return this;
};
/**
* Set _Content-Disposition_ header to _attachment_ with optional `filename`.
*
* @param {String} filename
* @return {ServerResponse}
* @public
*/
res.attachment = function attachment(filename) {
if (filename) {
this.type(extname(filename));
}
this.set('Content-Disposition', contentDisposition(filename));
return this;
};
/**
* Append additional header `field` with value `val`.
*
* Example:
*
* res.append('Link', ['<http://localhost/>', '<http://localhost:3000/>']);
* res.append('Set-Cookie', 'foo=bar; Path=/; HttpOnly');
* res.append('Warning', '199 Miscellaneous warning');
*
* @param {String} field
* @param {String|Array} val
* @return {ServerResponse} for chaining
* @public
*/
res.append = function append(field, val) {
var prev = this.get(field);
var value = val;
if (prev) {
// concat the new and prev vals
value = Array.isArray(prev) ? prev.concat(val)
: Array.isArray(val) ? [prev].concat(val)
: [prev, val]
}
return this.set(field, value);
};
/**
* Set header `field` to `val`, or pass
* an object of header fields.
*
* Examples:
*
* res.set('Foo', ['bar', 'baz']);
* res.set('Accept', 'application/json');
* res.set({ Accept: 'text/plain', 'X-API-Key': 'tobi' });
*
* Aliased as `res.header()`.
*
* When the set header is "Content-Type", the type is expanded to include
* the charset if not present using `mime.contentType()`.
*
* @param {String|Object} field
* @param {String|Array} val
* @return {ServerResponse} for chaining
* @public
*/
res.set =
res.header = function header(field, val) {
if (arguments.length === 2) {
var value = Array.isArray(val)
? val.map(String)
: String(val);
// add charset to content-type
if (field.toLowerCase() === 'content-type') {
if (Array.isArray(value)) {
throw new TypeError('Content-Type cannot be set to an Array');
}
value = mime.contentType(value)
}
this.setHeader(field, value);
} else {
for (var key in field) {
this.set(key, field[key]);
}
}
return this;
};
/**
* Get value for header `field`.
*
* @param {String} field
* @return {String}
* @public
*/
res.get = function(field){
return this.getHeader(field);
};
/**
* Clear cookie `name`.
*
* @param {String} name
* @param {Object} [options]
* @return {ServerResponse} for chaining
* @public
*/
res.clearCookie = function clearCookie(name, options) {
// Force cookie expiration by setting expires to the past
const opts = { path: '/', ...options, expires: new Date(1)};
// ensure maxAge is not passed
delete opts.maxAge
return this.cookie(name, '', opts);
};
/**
* Set cookie `name` to `value`, with the given `options`.
*
* Options:
*
* - `maxAge` max-age in milliseconds, converted to `expires`
* - `signed` sign the cookie
* - `path` defaults to "/"
*
* Examples:
*
* // "Remember Me" for 15 minutes
* res.cookie('rememberme', '1', { expires: new Date(Date.now() + 900000), httpOnly: true });
*
* // same as above
* res.cookie('rememberme', '1', { maxAge: 900000, httpOnly: true })
*
* @param {String} name
* @param {String|Object} value
* @param {Object} [options]
* @return {ServerResponse} for chaining
* @public
*/
res.cookie = function (name, value, options) {
var opts = merge({}, options);
var secret = this.req.secret;
var signed = opts.signed;
if (signed && !secret) {
throw new Error('cookieParser("secret") required for signed cookies');
}
var val = typeof value === 'object'
? 'j:' + JSON.stringify(value)
: String(value);
if (signed) {
val = 's:' + sign(val, secret);
}
if (opts.maxAge != null) {
var maxAge = opts.maxAge - 0
if (!isNaN(maxAge)) {
opts.expires = new Date(Date.now() + maxAge)
opts.maxAge = Math.floor(maxAge / 1000)
}
}
if (opts.path == null) {
opts.path = '/';
}
this.append('Set-Cookie', cookie.serialize(name, String(val), opts));
return this;
};
/**
* Set the location header to `url`.
*
* The given `url` can also be "back", which redirects
* to the _Referrer_ or _Referer_ headers or "/".
*
* Examples:
*
* res.location('/foo/bar').;
* res.location('http://example.com');
* res.location('../login');
*
* @param {String} url
* @return {ServerResponse} for chaining
* @public
*/
res.location = function location(url) {
return this.set('Location', encodeUrl(url));
};
/**
* Redirect to the given `url` with optional response `status`
* defaulting to 302.
*
* Examples:
*
* res.redirect('/foo/bar');
* res.redirect('http://example.com');
* res.redirect(301, 'http://example.com');
* res.redirect('../login'); // /blog/post/1 -> /blog/login
*
* @public
*/
res.redirect = function redirect(url) {
var address = url;
var body;
var status = 302;
// allow status / url
if (arguments.length === 2) {
status = arguments[0]
address = arguments[1]
}
// Set location header
address = this.location(address).get('Location');
// Support text/{plain,html} by default
this.format({
text: function(){
body = statuses.message[status] + '. Redirecting to ' + address
},
html: function(){
var u = escapeHtml(address);
body = '<p>' + statuses.message[status] + '. Redirecting to ' + u + '</p>'
},
default: function(){
body = '';
}
});
// Respond
this.status(status);
this.set('Content-Length', Buffer.byteLength(body));
if (this.req.method === 'HEAD') {
this.end();
} else {
this.end(body);
}
};
/**
* Add `field` to Vary. If already present in the Vary set, then
* this call is simply ignored.
*
* @param {Array|String} field
* @return {ServerResponse} for chaining
* @public
*/
res.vary = function(field){
vary(this, field);
return this;
};
/**
* Render `view` with the given `options` and optional callback `fn`.
* When a callback function is given a response will _not_ be made
* automatically, otherwise a response of _200_ and _text/html_ is given.
*
* Options:
*
* - `cache` boolean hinting to the engine it should cache
* - `filename` filename of the view being rendered
*
* @public
*/
res.render = function render(view, options, callback) {
var app = this.req.app;
var done = callback;
var opts = options || {};
var req = this.req;
var self = this;
// support callback function as second arg
if (typeof options === 'function') {
done = options;
opts = {};
}
// merge res.locals
opts._locals = self.locals;
// default callback to respond
done = done || function (err, str) {
if (err) return req.next(err);
self.send(str);
};
// render
app.render(view, opts, done);
};
// pipe the send file stream
function sendfile(res, file, options, callback) {
var done = false;
var streaming;
// request aborted
function onaborted() {
if (done) return;
done = true;
var err = new Error('Request aborted');
err.code = 'ECONNABORTED';
callback(err);
}
// directory
function ondirectory() {
if (done) return;
done = true;
var err = new Error('EISDIR, read');
err.code = 'EISDIR';
callback(err);
}
// errors
function onerror(err) {
if (done) return;
done = true;
callback(err);
}
// ended
function onend() {
if (done) return;
done = true;
callback();
}
// file
function onfile() {
streaming = false;
}
// finished
function onfinish(err) {
if (err && err.code === 'ECONNRESET') return onaborted();
if (err) return onerror(err);
if (done) return;
setImmediate(function () {
if (streaming !== false && !done) {
onaborted();
return;
}
if (done) return;
done = true;
callback();
});
}
// streaming
function onstream() {
streaming = true;
}
file.on('directory', ondirectory);
file.on('end', onend);
file.on('error', onerror);
file.on('file', onfile);
file.on('stream', onstream);
onFinished(res, onfinish);
if (options.headers) {
// set headers on successful transfer
file.on('headers', function headers(res) {
var obj = options.headers;
var keys = Object.keys(obj);
for (var i = 0; i < keys.length; i++) {
var k = keys[i];
res.setHeader(k, obj[k]);
}
});
}
// pipe
file.pipe(res);
}
/**
* Stringify JSON, like JSON.stringify, but v8 optimized, with the
* ability to escape characters that can trigger HTML sniffing.
*
* @param {*} value
* @param {function} replacer
* @param {number} spaces
* @param {boolean} escape
* @returns {string}
* @private
*/
function stringify (value, replacer, spaces, escape) {
// v8 checks arguments.length for optimizing simple call
// https://bugs.chromium.org/p/v8/issues/detail?id=4730
var json = replacer || spaces
? JSON.stringify(value, replacer, spaces)
: JSON.stringify(value);
if (escape && typeof json === 'string') {
json = json.replace(/[<>&]/g, function (c) {
switch (c.charCodeAt(0)) {
case 0x3c:
return '\\u003c'
case 0x3e:
return '\\u003e'
case 0x26:
return '\\u0026'
/* istanbul ignore next: unreachable default */
default:
return c
}
})
}
return json
}