# http-proxy-middleware
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Node.js proxying made simple. Configure proxy middleware with ease for [connect](https://github.com/senchalabs/connect), [express](https://github.com/strongloop/express), [browser-sync](https://github.com/BrowserSync/browser-sync) and [many more](#compatible-servers).
Powered by the popular Nodejitsu [`http-proxy`](https://github.com/nodejitsu/node-http-proxy). [](https://github.com/nodejitsu/node-http-proxy)
## TL;DR
Proxy `/api` requests to `http://www.example.org`
```javascript
var express = require('express')
var proxy = require('http-proxy-middleware')
var app = express()
app.use('/api', proxy({ target: 'http://www.example.org', changeOrigin: true }))
app.listen(3000)
// http://localhost:3000/api/foo/bar -> http://www.example.org/api/foo/bar
```
_All_ `http-proxy` [options](https://github.com/nodejitsu/node-http-proxy#options) can be used, along with some extra `http-proxy-middleware` [options](#options).
:bulb: **Tip:** Set the option `changeOrigin` to `true` for [name-based virtual hosted sites](http://en.wikipedia.org/wiki/Virtual_hosting#Name-based).
## Table of Contents
- [Install](#install)
- [Core concept](#core-concept)
- [Example](#example)
- [Context matching](#context-matching)
- [Options](#options)
- [http-proxy-middleware options](#http-proxy-middleware-options)
- [http-proxy events](#http-proxy-events)
- [http-proxy options](#http-proxy-options)
- [Shorthand](#shorthand)
- [app.use\(path, proxy\)](#appusepath-proxy)
- [WebSocket](#websocket)
- [External WebSocket upgrade](#external-websocket-upgrade)
- [Working examples](#working-examples)
- [Recipes](#recipes)
- [Compatible servers](#compatible-servers)
- [Tests](#tests)
- [Changelog](#changelog)
- [License](#license)
## Install
```javascript
$ npm install --save-dev http-proxy-middleware
```
## Core concept
Proxy middleware configuration.
#### proxy([context,] config)
```javascript
var proxy = require('http-proxy-middleware')
var apiProxy = proxy('/api', { target: 'http://www.example.org' })
// \____/ \_____________________________/
// 'apiProxy' is now ready to be used as middleware in a server.
```
- **context**: Determine which requests should be proxied to the target host.
(more on [context matching](#context-matching))
- **options.target**: target host to proxy to. _(protocol + host)_
(full list of [`http-proxy-middleware` configuration options](#options))
#### proxy(uri [, config])
```javascript
// shorthand syntax for the example above:
var apiProxy = proxy('http://www.example.org/api')
```
More about the [shorthand configuration](#shorthand).
## Example
An example with `express` server.
```javascript
// include dependencies
var express = require('express')
var proxy = require('http-proxy-middleware')
// proxy middleware options
var options = {
target: 'http://www.example.org', // target host
changeOrigin: true, // needed for virtual hosted sites
ws: true, // proxy websockets
pathRewrite: {
'^/api/old-path': '/api/new-path', // rewrite path
'^/api/remove/path': '/path' // remove base path
},
router: {
// when request.headers.host == 'dev.localhost:3000',
// override target 'http://www.example.org' to 'http://localhost:8000'
'dev.localhost:3000': 'http://localhost:8000'
}
}
// create the proxy (without context)
var exampleProxy = proxy(options)
// mount `exampleProxy` in web server
var app = express()
app.use('/api', exampleProxy)
app.listen(3000)
```
## Context matching
Providing an alternative way to decide which requests should be proxied; In case you are not able to use the server's [`path` parameter](http://expressjs.com/en/4x/api.html#app.use) to mount the proxy or when you need more flexibility.
[RFC 3986 `path`](https://tools.ietf.org/html/rfc3986#section-3.3) is used for context matching.
```
foo://example.com:8042/over/there?name=ferret#nose
\_/ \______________/\_________/ \_________/ \__/
| | | | |
scheme authority path query fragment
```
- **path matching**
- `proxy({...})` - matches any path, all requests will be proxied.
- `proxy('/', {...})` - matches any path, all requests will be proxied.
- `proxy('/api', {...})` - matches paths starting with `/api`
- **multiple path matching**
- `proxy(['/api', '/ajax', '/someotherpath'], {...})`
- **wildcard path matching**
For fine-grained control you can use wildcard matching. Glob pattern matching is done by _micromatch_. Visit [micromatch](https://www.npmjs.com/package/micromatch) or [glob](https://www.npmjs.com/package/glob) for more globbing examples.
- `proxy('**', {...})` matches any path, all requests will be proxied.
- `proxy('**/*.html', {...})` matches any path which ends with `.html`
- `proxy('/*.html', {...})` matches paths directly under path-absolute
- `proxy('/api/**/*.html', {...})` matches requests ending with `.html` in the path of `/api`
- `proxy(['/api/**', '/ajax/**'], {...})` combine multiple patterns
- `proxy(['/api/**', '!**/bad.json'], {...})` exclusion
**Note**: In multiple path matching, you cannot use string paths and wildcard paths together.
- **custom matching**
For full control you can provide a custom function to determine which requests should be proxied or not.
```javascript
var filter = function(pathname, req) {
return pathname.match('^/api') && req.method === 'GET'
}
var apiProxy = proxy(filter, { target: 'http://www.example.org' })
```
## Options
### http-proxy-middleware options
- **option.pathRewrite**: object/function, rewrite target's url path. Object-keys will be used as _RegExp_ to match paths.
```javascript
pathRewrite: {'^/old/api' : '/new/api'}
pathRewrite: {'^/remove/api' : ''}
pathRewrite: {'^/' : '/basepath/'}
pathRewrite: function (path, req) { return path.replace('/api', '/base/api') }
```
- **option.router**: object/function, re-target `option.target` for specific requests.
```javascript
router: {
'integration.localhost:3000' : 'http://localhost:8001', 'staging.localhost:3000' : 'http://localhost:8002', 'localhost:3000/api' : 'http://localhost:8003', '/rest' : 'http://localhost:8004' }
router: function(req) {
return 'http://localhost:8004';
}
```
- **option.logLevel**: string, ['debug', 'info', 'warn', 'error', 'silent']. Default: `'info'`
- **option.logProvider**: function, modify or replace log provider. Default: `console`.
```javascript
function logProvider(provider) {
return require('winston')
}
```
```javascript
function logProvider(provider) {
var logger = new (require('winston')).Logger()
var myCustomProvider = {
log: logger.log,
debug: logger.debug,
info: logger.info,
warn: logger.warn,
error: logger.error
}
return myCustomProvider
}
```
- (DEPRECATED) **option.proxyHost**: Use `option.changeOrigin = true` instead.
- (DEPRECATED) **option.proxyTable**: Use `option.router` instead.
### http-proxy events
Subscribe to [http-proxy events](https://github.com/nodejitsu/node-http-proxy#listening-for-proxy-events):
- **option.onError**: function, subscribe to http-proxy's `error` event for custom error handling.
```javascript
function onError(err, req, res) {
res.writeHead(500, {
'Content-Type': 'text/plain'
})
res.end(
'Something went wrong. And we are reporting a custom error message.'
)
}
```
- **option.onProxyRes**: function, subscribe to http-proxy's `proxyRes` event.
```javascript
function onProxyRes(proxyRes, req, res) {
proxyRes.headers['x-added'] = 'foobar' delete proxyRes.headers['x-removed'] }
```
- **option.onProxyReq**: function, subscribe to http-proxy's `proxyReq` event.
```javascript
function onProxyReq(proxyReq, req, res) {
proxyReq.setHeader('x-added', 'foobar')
}
```
- **option.onProxyReqWs**: function, subscribe to http-proxy's `proxyReqWs` event.
```javascript
function onProxyReqWs(proxyReq, req, socket, options, head) {
proxyReq.setHeader('X-Special-Proxy-Header', 'foobar')
}
```
- **option.onOpen**: function, subscribe to http-proxy's `open` event.
```javascript
function onOpen(proxySocket) {
proxySocket.on('data', hybiParseAndLogMessage)
}
```
- **option.onClose**: function, subscribe to http-proxy's `close` event.
```javascript
function onClose(res, socket, head) {
console.log('Client disconnected')
}
```
### http-proxy options
The following options are provided by the underlying [http-proxy](https://github.com/nodejitsu/node-http-proxy#options) library.
- **option.target**: url string to be parsed with the url module
- **option.forward**: url string to be parsed with the url module
- **option.agent**: object to be passed to http(s).request (see Node's [https agent](http://nodejs.org/api/https.html#https_class_https_agent) and [http agent](http://nodejs.org/api/http.html#http_class_http_agent) objects)
- **option.ssl**: object to be passed to https.createServer()
- **option.ws**: true/false: if you want to proxy websockets
- **option.xfwd**: true/false, adds x-forward headers
- **option.secure**: true/false, if you want to verify the SSL Certs
- **option.toProxy**: true/false, passes the absolute URL as the `path` (useful for proxying to proxies)
- **option.prependPath**: true/false, Default: true - specify whether you want to prepend the target's path to the proxy path
- **option.ignorePath**: true/false, Default: false - specify whether you want to ignore the proxy path of the incoming request (note: you will have to append / manually if required).
- **option.localAddress** : Local interface string to bind for outgoing connections
- **option.changeOrigin**: true/false, Default: false - changes the origin of the host header to the target URL
- **option.preserveHeaderKeyCase**: true/false, Default: false - specify whether you want to keep letter case of response header key
- **option.auth** : Basic authentication i.e. 'user:password' to compute an Authorization header.
- **option.hostRewrite**: rewrites the location hostname on (301/302/307/308) redirects.
- **option.autoRewrite**: rewrites the location host/port on (301/302/307/308) redirects based on requested host/port. Default: false.
- **option.protocolRewrite**: rewrites the location protocol on (301/302/307/308) redirects to 'http' or 'https'. Default: null.
- **option.cookieDomainRewrite**: rewrites domain of `set-cookie` headers. Possible values:
- `false` (default): disable cookie rewriting
- String: new domain, for example `cookieDomainRewrite: "new.domain"`. To remove the domain, use `cookieDomainRewrite: ""`.
- Object: mapping of domains to new domains, use `"*"` to match all domains.
For example keep one domain unchanged, rewrite one domain and remove other domains:
```
cookieDomainRewrite: {
"unchanged.domain": "unchanged.domain",
"old.domain": "new.domain",
"*": ""
}
```
- **option.cookiePathRewrite**: rewrites path of `set-cookie` headers. Possible values:
- `false` (default): disable cookie rewriting
- String: new path, for example `cookiePathRewrite: "/newPath/"`. To remove the path, use `cookiePathRewrite: ""`. To set path to root use `cookiePathRewrite: "/"`.
- Object: mapping of paths to new paths, use `"*"` to match all paths.
For example, to keep one path unchanged, rewrite one path and remove other paths:
```
cookiePathRewrite: {
"/unchanged.path/": "/unchanged.path/",
"/old.path/": "/new.path/",
"*": ""
}
```
- **option.headers**: object, adds [request headers](https://en.wikipedia.org/wiki/List_of_HTTP_header_fields#Request_fields). (Example: `{host:'www.example.org'}`)
- **option.proxyTimeout**: timeout (in millis) when proxy receives no response from target
- **option.timeout**: timeout (in millis) for incoming requests
- **option.followRedirects**: true/false, Default: false - specify whether you want to follow redirects
- **option.selfHandleResponse** true/false, if set to true, none of the webOutgoing passes are called and it's your responsibility to appropriately return the response by listening and acting on the `proxyRes` event
- **option.buffer**: stream of data to send as the request body. Maybe you have some middleware that consumes the request stream before proxying it on e.g. If you read the body of a request into a field called 'req.rawbody' you could restream this field in the buffer option:
```
'use strict';
const streamify = require('stream-array');
const HttpProxy = require('http-proxy');
const proxy = new HttpProxy();
module.exports = (req, res, next) => {
proxy.web(req, res, {
target: 'http://localhost:4003/',
buffer: streamify(req.rawBody)
}, next);
};
```
## Shorthand
Use the shorthand syntax when verbose configuration is not needed. The `context` and `option.target` will be automatically configured when shorthand is used. Options can still be used if needed.
```javascript
proxy('http://www.example.org:8000/api')
// proxy('/api', {target: 'http://www.example.org:8000'});
proxy('http://www.example.org:8000/api/books/*/**.json')
// proxy('/api/books/*/**.json', {target: 'http://www.example.org:8000'});
proxy('http://www.example.org:8000/api', { changeOrigin: true })
// proxy('/api', {target: 'http://www.example.org:8000', changeOrigin: true});
```
### app.use(path, proxy)
If you want to use the server's `app.use` `path` parameter to match requests;
Create and mount the proxy without the http-proxy-middleware `context` parameter:
```javascript
app.use('/api', proxy({ target: 'http://www.example.org', changeOrigin: true }))
```
`app.use` documentation:
- express: http://expressjs.com/en/4x/api.html#app.use
- connect: https://github.com/senchalabs/connect#mount-middleware
## WebSocket
```javascript
// verbose api
proxy('/', { target: 'http://echo.websocket.org', ws: true })
// shorthand
proxy('http://echo.websocket.org', { ws: true })
// shorter shorthand
proxy('ws://echo.websocket.org')
```
### External WebSocket upgrade
In the previous WebSocket examples, http-proxy-middleware relies on a initial http request in order to listen to the http `upgrade` event. If you need to proxy WebSockets without the initial http request, you can subscribe to the server's http `upgrade` event manually.
```javascript
var wsProxy = proxy('ws://echo.websocket.org', { changeOrigin: true })
var app = express()
app.use(wsProxy)
var server = app.listen(3000)
server.on('upgrade', wsProxy.upgrade) // <-- subscribe to http 'upgrade'
```
## Working examples
View and play around with [working examples](https://github.com/chimurai/http-proxy-middleware/tree/master/examples).
- Browser-Sync ([example source](https://github.com/chimurai/http-proxy-middleware/tree/master/examples/browser-sync/index.js))
- express ([example source](https://github.com/chimurai/http-proxy-middleware/tree/master/examples/express/index.js))
- connect ([example source](https://github.com/chimurai/http-proxy-middleware/tree/master/examples/connect/index.js))
- WebSocket ([example source](https://github.com/chimurai/http-proxy-middleware/tree/master/examples/websocket/index.js))
## Recipes
View the [recipes](https://github.com/chimurai/http-proxy-middleware/tree/master/recipes) for common use cases.
## Compatible servers
`http-proxy-middleware` is compatible with the following servers:
- [connect](https://www.npmjs.com/package/connect)
- [express](https://www.npmjs.com/package/express)
- [browser-sync](https://www.npmjs.com/package/browser-sync)
- [lite-server](https://www.npmjs.com/package/lite-server)
- [grunt-contrib-connect](https://www.npmjs.com/package/grunt-contrib-connect)
- [grunt-browser-sync](https://www.npmjs.com/package/grunt-browser-sync)
- [gulp-connect](https://www.npmjs.com/package/gulp-connect)
- [gulp-webserver](https://www.npmjs.com/package/gulp-webserver)
Sample implementations can be found in the [server recipes](https://github.com/chimurai/http-proxy-middleware/tree/master/recipes/servers.md).
## Tests
Run the test suite:
```bash
# install dependencies
$ npm install
# linting
$ npm run lint
# unit tests
$ npm test
# code coverage
$ npm run cover
```
## Changelog
- [View changelog](https://github.com/chimurai/http-proxy-middleware/blob/master/CHANGELOG.md)
## License
The MIT License (MIT)
Copyright (c) 2015-2018 Steven Chim