Node.js proxying made simple. Configure proxy middleware with ease for connect, express, browser-sync and many more.
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This page is showing documentation for version v2.x.x (release notes)
If you're looking for v0.x documentation. Go to: https://github.com/chimurai/http-proxy-middleware/tree/v0.21.0#readme
Proxy /api requests to http://www.example.org
```javascript // javascript
const express = require('express'); const { createProxyMiddleware } = require('http-proxy-middleware');
const app = express();
app.use('/api', createProxyMiddleware({ target: 'http://www.example.org', changeOrigin: true })); app.listen(3000);
// http://localhost:3000/api/foo/bar -> http://www.example.org/api/foo/bar ```
```typescript // typescript
import * as express from 'express'; import { createProxyMiddleware, Filter, Options, RequestHandler } from 'http-proxy-middleware';
const app = express();
app.use('/api', createProxyMiddleware({ 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 can be used, along with some extra http-proxy-middleware options.
:bulb: Tip: Set the option changeOrigin to true for name-based virtual hosted sites.
bash
$ npm install --save-dev http-proxy-middleware
Proxy middleware configuration.
```javascript const { createProxyMiddleware } = require('http-proxy-middleware');
const apiProxy = createProxyMiddleware('/api', { target: 'http://www.example.org' }); // _/ ________/ // | | // context options
// 'apiProxy' is now ready to be used as middleware in a server. ```
(full list of http-proxy-middleware configuration options)
javascript
// shorthand syntax for the example above:
const apiProxy = createProxyMiddleware('http://www.example.org/api');
More about the shorthand configuration.
An example with express server.
```javascript // include dependencies const express = require('express'); const { createProxyMiddleware } = require('http-proxy-middleware');
// proxy middleware options /* @type {import('http-proxy-middleware/dist/types').Options} / const 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) const exampleProxy = createProxyMiddleware(options);
// mount exampleProxy in web server
const app = express();
app.use('/api', exampleProxy);
app.listen(3000);
```
Providing an alternative way to decide which requests should be proxied; In case you are not able to use the server's path parameter to mount the proxy or when you need more flexibility.
RFC 3986 path is used for context matching.
ascii
foo://example.com:8042/over/there?name=ferret#nose
\_/ \______________/\_________/ \_________/ \__/
| | | | |
scheme authority path query fragment
path matching
createProxyMiddleware({...}) - matches any path, all requests will be proxied.
createProxyMiddleware('/', {...}) - matches any path, all requests will be proxied.createProxyMiddleware('/api', {...}) - matches paths starting with /api
multiple path matching
createProxyMiddleware(['/api', '/ajax', '/someotherpath'], {...})
wildcard path matching
For fine-grained control you can use wildcard matching. Glob pattern matching is done by micromatch. Visit micromatch or glob for more globbing examples.
createProxyMiddleware('**', {...}) matches any path, all requests will be proxied.createProxyMiddleware('**/*.html', {...}) matches any path which ends with .htmlcreateProxyMiddleware('/*.html', {...}) matches paths directly under path-absolutecreateProxyMiddleware('/api/**/*.html', {...}) matches requests ending with .html in the path of /apicreateProxyMiddleware(['/api/**', '/ajax/**'], {...}) combine multiple patternscreateProxyMiddleware(['/api/**', '!**/bad.json'], {...}) exclusionNote: In multiple path matching, you cannot use string paths and wildcard paths together.
For full control you can provide a custom function to determine which requests should be proxied or not.
```javascript /* * @return {Boolean} / const filter = function (pathname, req) { return pathname.match('^/api') && req.method === 'GET'; };
const apiProxy = createProxyMiddleware(filter, { target: 'http://www.example.org', }); ```
```javascript // rewrite path pathRewrite: {'^/old/api' : '/new/api'}
// remove path pathRewrite: {'^/remove/api' : ''}
// add base path pathRewrite: {'^/' : '/basepath/'}
// custom rewriting pathRewrite: function (path, req) { return path.replace('/api', '/base/api') }
// custom rewriting, returning Promise pathRewrite: async function (path, req) { const should_add_something = await httpRequestToDecideSomething(path); if (should_add_something) path += "something"; return path; } ```
option.target for specific requests.``javascript
// Usehostand/orpath` to match requests. First match will be used.
// The order of the configuration matters.
router: {
'integration.localhost:3000' : 'http://localhost:8001', // host only
'staging.localhost:3000' : 'http://localhost:8002', // host only
'localhost:3000/api' : 'http://localhost:8003', // host + path
'/rest' : 'http://localhost:8004' // path only
}
// Custom router function (string target) router: function(req) { return 'http://localhost:8004'; }
// Custom router function (target object) router: function(req) { return { protocol: 'https:', // The : is required host: 'localhost', port: 8004 }; }
// Asynchronous router function which returns promise router: async function(req) { const url = await doSomeIO(); return url; } ```
option.logLevel: string, ['debug', 'info', 'warn', 'error', 'silent']. Default: 'info'
option.logProvider: function, modify or replace log provider. Default: console.
javascript
// simple replace
function logProvider(provider) {
// replace the default console log provider.
return require('winston');
}
```javascript // verbose replacement function logProvider(provider) { const logger = new (require('winston').Logger)();
const myCustomProvider = {
log: logger.log,
debug: logger.debug,
info: logger.info,
warn: logger.warn,
error: logger.error,
};
return myCustomProvider;
} ```
Subscribe to http-proxy events:
error event for custom error handling.javascript
function onError(err, req, res, target) {
res.writeHead(500, {
'Content-Type': 'text/plain',
});
res.end('Something went wrong. And we are reporting a custom error message.');
}
proxyRes event.javascript
function onProxyRes(proxyRes, req, res) {
proxyRes.headers['x-added'] = 'foobar'; // add new header to response
delete proxyRes.headers['x-removed']; // remove header from response
}
proxyReq event.javascript
function onProxyReq(proxyReq, req, res) {
// add custom header to request
proxyReq.setHeader('x-added', 'foobar');
// or log the req
}
proxyReqWs event.javascript
function onProxyReqWs(proxyReq, req, socket, options, head) {
// add custom header
proxyReq.setHeader('X-Special-Proxy-Header', 'foobar');
}
open event.javascript
function onOpen(proxySocket) {
// listen for messages coming FROM the target here
proxySocket.on('data', hybridParseAndLogMessage);
}
close event.javascript
function onClose(res, socket, head) {
// view disconnected websocket connections
console.log('Client disconnected');
}
The following options are provided by the underlying http-proxy library.
path (useful for proxying to proxies)set-cookie headers. Possible values:false (default): disable cookie rewritingcookieDomainRewrite: "new.domain". To remove the domain, use cookieDomainRewrite: ""."*" to match all domains.json
cookieDomainRewrite: {
"unchanged.domain": "unchanged.domain",
"old.domain": "new.domain",
"*": ""
}set-cookie headers. Possible values:false (default): disable cookie rewritingcookiePathRewrite: "/newPath/". To remove the path, use cookiePathRewrite: "". To set path to root use cookiePathRewrite: "/"."*" to match all paths.
For example, to keep one path unchanged, rewrite one path and remove other paths:
json
cookiePathRewrite: {
"/unchanged.path/": "/unchanged.path/",
"/old.path/": "/new.path/",
"*": ""
}{host:'www.example.org'})proxyRes event```javascript '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 ); }; ```
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 createProxyMiddleware('http://www.example.org:8000/api'); // createProxyMiddleware('/api', {target: 'http://www.example.org:8000'});
createProxyMiddleware('http://www.example.org:8000/api/books//.json'); // createProxyMiddleware('/api/books//**.json', {target: 'http://www.example.org:8000'});
createProxyMiddleware('http://www.example.org:8000/api', { changeOrigin: true }); // createProxyMiddleware('/api', {target: 'http://www.example.org:8000', changeOrigin: true}); ```
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', createProxyMiddleware({ target: 'http://www.example.org', changeOrigin: true }));
app.use documentation:
```javascript // verbose api createProxyMiddleware('/', { target: 'http://echo.websocket.org', ws: true });
// shorthand createProxyMiddleware('http://echo.websocket.org', { ws: true });
// shorter shorthand createProxyMiddleware('ws://echo.websocket.org'); ```
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 const wsProxy = createProxyMiddleware('ws://echo.websocket.org', { changeOrigin: true });
const app = express(); app.use(wsProxy);
const server = app.listen(3000); server.on('upgrade', wsProxy.upgrade); // <-- subscribe to http 'upgrade' ```
Intercept requests from downstream by defining onProxyReq in createProxyMiddleware.
Currently the only pre-provided request interceptor is fixRequestBody, which is used to fix proxied POST requests when bodyParser is applied before this middleware.
Example:
```javascript const { createProxyMiddleware, fixRequestBody } = require('http-proxy-middleware');
const proxy = createProxyMiddleware({ / * Fix bodyParser / onProxyReq: fixRequestBody, }); ```
Intercept responses from upstream with responseInterceptor. (Make sure to set selfHandleResponse: true)
Responses which are compressed with brotli, gzip and deflate will be decompressed automatically. The response will be returned as buffer (docs) which you can manipulate.
With buffer, response manipulation is not limited to text responses (html/css/js, etc...); image manipulation will be possible too. (example)
NOTE: responseInterceptor disables streaming of target's response.
Example:
```javascript const { createProxyMiddleware, responseInterceptor } = require('http-proxy-middleware');
const proxy = createProxyMiddleware({ / * IMPORTANT: avoid res.end being called automatically / selfHandleResponse: true, // res.end() will be called internally by responseInterceptor()
/ * Intercept response and replace 'Hello' with 'Goodbye' / onProxyRes: responseInterceptor(async (responseBuffer, proxyRes, req, res) => { const response = responseBuffer.toString('utf8'); // convert buffer to string return response.replace('Hello', 'Goodbye'); // manipulate response and return the result }), }); ```
Check out interception recipes for more examples.
View and play around with working examples.
View the recipes for common use cases.
http-proxy-middleware is compatible with the following servers:
Sample implementations can be found in the server recipes.
Run the test suite:
```bash
$ yarn
$ yarn lint $ yarn lint:fix
$ yarn build
$ yarn test
$ yarn cover
$ yarn spellcheck ```
The MIT License (MIT)
Copyright (c) 2015-2022 Steven Chim