599 lines
		
	
	
		
			22 KiB
		
	
	
	
		
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			599 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| # http-proxy-middleware
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| 
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| [](https://github.com/chimurai/http-proxy-middleware/actions?query=branch%3Amaster)
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| [](https://coveralls.io/r/chimurai/http-proxy-middleware)
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| [](https://snyk.io/test/npm/http-proxy-middleware)
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| [](https://www.npmjs.com/package/http-proxy-middleware)
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| 
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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).
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| 
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| Powered by the popular Nodejitsu [`http-proxy`](https://github.com/nodejitsu/node-http-proxy). [](https://github.com/nodejitsu/node-http-proxy)
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| 
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| ## ⚠️ Note <!-- omit in toc -->
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| 
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| This page is showing documentation for version v2.x.x ([release notes](https://github.com/chimurai/http-proxy-middleware/releases))
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| 
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| If you're looking for v0.x documentation. Go to:
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| https://github.com/chimurai/http-proxy-middleware/tree/v0.21.0#readme
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| 
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| ## TL;DR <!-- omit in toc -->
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| 
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| Proxy `/api` requests to `http://www.example.org`
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| 
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| ```javascript
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| // javascript
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| 
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| const express = require('express');
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| const { createProxyMiddleware } = require('http-proxy-middleware');
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| 
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| const app = express();
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| 
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| app.use('/api', createProxyMiddleware({ target: 'http://www.example.org', changeOrigin: true }));
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| app.listen(3000);
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| 
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| // http://localhost:3000/api/foo/bar -> http://www.example.org/api/foo/bar
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| ```
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| 
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| ```typescript
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| // typescript
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| 
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| import * as express from 'express';
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| import { createProxyMiddleware, Filter, Options, RequestHandler } from 'http-proxy-middleware';
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| 
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| const app = express();
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| 
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| app.use('/api', createProxyMiddleware({ target: 'http://www.example.org', changeOrigin: true }));
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| app.listen(3000);
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| 
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| // http://localhost:3000/api/foo/bar -> http://www.example.org/api/foo/bar
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| ```
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| 
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| _All_ `http-proxy` [options](https://github.com/nodejitsu/node-http-proxy#options) can be used, along with some extra `http-proxy-middleware` [options](#options).
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| 
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| :bulb: **Tip:** Set the option `changeOrigin` to `true` for [name-based virtual hosted sites](http://en.wikipedia.org/wiki/Virtual_hosting#Name-based).
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| 
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| ## Table of Contents <!-- omit in toc -->
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| 
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| - [Install](#install)
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| - [Core concept](#core-concept)
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| - [Example](#example)
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| - [Context matching](#context-matching)
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| - [Options](#options)
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|   - [http-proxy-middleware options](#http-proxy-middleware-options)
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|   - [http-proxy events](#http-proxy-events)
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|   - [http-proxy options](#http-proxy-options)
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| - [Shorthand](#shorthand)
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|   - [app.use(path, proxy)](#appusepath-proxy)
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| - [WebSocket](#websocket)
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|   - [External WebSocket upgrade](#external-websocket-upgrade)
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| - [Intercept and manipulate requests](#intercept-and-manipulate-requests)
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| - [Intercept and manipulate responses](#intercept-and-manipulate-responses)
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| - [Working examples](#working-examples)
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| - [Recipes](#recipes)
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| - [Compatible servers](#compatible-servers)
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| - [Tests](#tests)
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| - [Changelog](#changelog)
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| - [License](#license)
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| 
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| ## Install
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| 
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| ```bash
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| $ npm install --save-dev http-proxy-middleware
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| ```
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| 
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| ## Core concept
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| 
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| Proxy middleware configuration.
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| 
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| #### createProxyMiddleware([context,] config)
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| 
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| ```javascript
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| const { createProxyMiddleware } = require('http-proxy-middleware');
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| 
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| const apiProxy = createProxyMiddleware('/api', { target: 'http://www.example.org' });
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| //                                    \____/   \_____________________________/
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| //                                      |                    |
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| //                                    context             options
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| 
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| // 'apiProxy' is now ready to be used as middleware in a server.
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| ```
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| 
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| - **context**: Determine which requests should be proxied to the target host.
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|   (more on [context matching](#context-matching))
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| - **options.target**: target host to proxy to. _(protocol + host)_
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| 
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| (full list of [`http-proxy-middleware` configuration options](#options))
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| 
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| #### createProxyMiddleware(uri [, config])
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| 
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| ```javascript
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| // shorthand syntax for the example above:
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| const apiProxy = createProxyMiddleware('http://www.example.org/api');
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| ```
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| 
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| More about the [shorthand configuration](#shorthand).
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| 
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| ## Example
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| 
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| An example with `express` server.
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| 
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| ```javascript
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| // include dependencies
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| const express = require('express');
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| const { createProxyMiddleware } = require('http-proxy-middleware');
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| 
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| // proxy middleware options
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| /** @type {import('http-proxy-middleware/dist/types').Options} */
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| const options = {
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|   target: 'http://www.example.org', // target host
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|   changeOrigin: true, // needed for virtual hosted sites
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|   ws: true, // proxy websockets
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|   pathRewrite: {
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|     '^/api/old-path': '/api/new-path', // rewrite path
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|     '^/api/remove/path': '/path', // remove base path
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|   },
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|   router: {
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|     // when request.headers.host == 'dev.localhost:3000',
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|     // override target 'http://www.example.org' to 'http://localhost:8000'
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|     'dev.localhost:3000': 'http://localhost:8000',
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|   },
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| };
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| 
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| // create the proxy (without context)
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| const exampleProxy = createProxyMiddleware(options);
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| 
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| // mount `exampleProxy` in web server
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| const app = express();
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| app.use('/api', exampleProxy);
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| app.listen(3000);
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| ```
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| 
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| ## Context matching
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| 
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| 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.
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| 
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| [RFC 3986 `path`](https://tools.ietf.org/html/rfc3986#section-3.3) is used for context matching.
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| 
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| ```ascii
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|          foo://example.com:8042/over/there?name=ferret#nose
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|          \_/   \______________/\_________/ \_________/ \__/
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|           |           |            |            |        |
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|        scheme     authority       path        query   fragment
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| ```
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| 
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| - **path matching**
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| 
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|   - `createProxyMiddleware({...})` - matches any path, all requests will be proxied.
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|   - `createProxyMiddleware('/', {...})` - matches any path, all requests will be proxied.
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|   - `createProxyMiddleware('/api', {...})` - matches paths starting with `/api`
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| 
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| - **multiple path matching**
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| 
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|   - `createProxyMiddleware(['/api', '/ajax', '/someotherpath'], {...})`
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| 
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| - **wildcard path matching**
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| 
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|   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.
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| 
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|   - `createProxyMiddleware('**', {...})` matches any path, all requests will be proxied.
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|   - `createProxyMiddleware('**/*.html', {...})` matches any path which ends with `.html`
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|   - `createProxyMiddleware('/*.html', {...})` matches paths directly under path-absolute
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|   - `createProxyMiddleware('/api/**/*.html', {...})` matches requests ending with `.html` in the path of `/api`
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|   - `createProxyMiddleware(['/api/**', '/ajax/**'], {...})` combine multiple patterns
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|   - `createProxyMiddleware(['/api/**', '!**/bad.json'], {...})` exclusion
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| 
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|   **Note**: In multiple path matching, you cannot use string paths and wildcard paths together.
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| 
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| - **custom matching**
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| 
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|   For full control you can provide a custom function to determine which requests should be proxied or not.
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| 
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|   ```javascript
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|   /**
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|    * @return {Boolean}
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|    */
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|   const filter = function (pathname, req) {
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|     return pathname.match('^/api') && req.method === 'GET';
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|   };
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| 
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|   const apiProxy = createProxyMiddleware(filter, {
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|     target: 'http://www.example.org',
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|   });
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|   ```
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| 
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| ## Options
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| 
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| ### http-proxy-middleware options
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| 
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| - **option.pathRewrite**: object/function, rewrite target's url path. Object-keys will be used as _RegExp_ to match paths.
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| 
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|   ```javascript
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|   // rewrite path
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|   pathRewrite: {'^/old/api' : '/new/api'}
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| 
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|   // remove path
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|   pathRewrite: {'^/remove/api' : ''}
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| 
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|   // add base path
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|   pathRewrite: {'^/' : '/basepath/'}
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| 
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|   // custom rewriting
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|   pathRewrite: function (path, req) { return path.replace('/api', '/base/api') }
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| 
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|   // custom rewriting, returning Promise
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|   pathRewrite: async function (path, req) {
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|     const should_add_something = await httpRequestToDecideSomething(path);
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|     if (should_add_something) path += "something";
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|     return path;
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|   }
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|   ```
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| 
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| - **option.router**: object/function, re-target `option.target` for specific requests.
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| 
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|   ```javascript
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|   // Use `host` and/or `path` to match requests. First match will be used.
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|   // The order of the configuration matters.
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|   router: {
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|       'integration.localhost:3000' : 'http://localhost:8001',  // host only
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|       'staging.localhost:3000'     : 'http://localhost:8002',  // host only
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|       'localhost:3000/api'         : 'http://localhost:8003',  // host + path
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|       '/rest'                      : 'http://localhost:8004'   // path only
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|   }
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| 
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|   // Custom router function (string target)
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|   router: function(req) {
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|       return 'http://localhost:8004';
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|   }
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| 
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|   // Custom router function (target object)
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|   router: function(req) {
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|       return {
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|           protocol: 'https:', // The : is required
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|           host: 'localhost',
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|           port: 8004
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|       };
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|   }
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| 
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|   // Asynchronous router function which returns promise
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|   router: async function(req) {
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|       const url = await doSomeIO();
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|       return url;
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|   }
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|   ```
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| 
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| - **option.logLevel**: string, ['debug', 'info', 'warn', 'error', 'silent']. Default: `'info'`
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| 
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| - **option.logProvider**: function, modify or replace log provider. Default: `console`.
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| 
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|   ```javascript
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|   // simple replace
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|   function logProvider(provider) {
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|     // replace the default console log provider.
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|     return require('winston');
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|   }
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|   ```
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| 
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|   ```javascript
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|   // verbose replacement
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|   function logProvider(provider) {
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|     const logger = new (require('winston').Logger)();
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| 
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|     const myCustomProvider = {
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|       log: logger.log,
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|       debug: logger.debug,
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|       info: logger.info,
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|       warn: logger.warn,
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|       error: logger.error,
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|     };
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|     return myCustomProvider;
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|   }
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|   ```
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| 
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| ### http-proxy events
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| 
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| Subscribe to [http-proxy events](https://github.com/nodejitsu/node-http-proxy#listening-for-proxy-events):
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| 
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| - **option.onError**: function, subscribe to http-proxy's `error` event for custom error handling.
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| 
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|   ```javascript
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|   function onError(err, req, res, target) {
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|     res.writeHead(500, {
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|       'Content-Type': 'text/plain',
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|     });
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|     res.end('Something went wrong. And we are reporting a custom error message.');
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|   }
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|   ```
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| 
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| - **option.onProxyRes**: function, subscribe to http-proxy's `proxyRes` event.
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| 
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|   ```javascript
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|   function onProxyRes(proxyRes, req, res) {
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|     proxyRes.headers['x-added'] = 'foobar'; // add new header to response
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|     delete proxyRes.headers['x-removed']; // remove header from response
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|   }
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|   ```
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| 
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| - **option.onProxyReq**: function, subscribe to http-proxy's `proxyReq` event.
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| 
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|   ```javascript
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|   function onProxyReq(proxyReq, req, res) {
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|     // add custom header to request
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|     proxyReq.setHeader('x-added', 'foobar');
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|     // or log the req
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|   }
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|   ```
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| 
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| - **option.onProxyReqWs**: function, subscribe to http-proxy's `proxyReqWs` event.
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| 
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|   ```javascript
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|   function onProxyReqWs(proxyReq, req, socket, options, head) {
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|     // add custom header
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|     proxyReq.setHeader('X-Special-Proxy-Header', 'foobar');
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|   }
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|   ```
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| 
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| - **option.onOpen**: function, subscribe to http-proxy's `open` event.
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| 
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|   ```javascript
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|   function onOpen(proxySocket) {
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|     // listen for messages coming FROM the target here
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|     proxySocket.on('data', hybridParseAndLogMessage);
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|   }
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|   ```
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| 
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| - **option.onClose**: function, subscribe to http-proxy's `close` event.
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| 
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|   ```javascript
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|   function onClose(res, socket, head) {
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|     // view disconnected websocket connections
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|     console.log('Client disconnected');
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|   }
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|   ```
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| 
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| ### http-proxy options
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| 
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| The following options are provided by the underlying [http-proxy](https://github.com/nodejitsu/node-http-proxy#options) library.
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| 
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| - **option.target**: url string to be parsed with the url module
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| - **option.forward**: url string to be parsed with the url module
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| - **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)
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| - **option.ssl**: object to be passed to https.createServer()
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| - **option.ws**: true/false: if you want to proxy websockets
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| - **option.xfwd**: true/false, adds x-forward headers
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| - **option.secure**: true/false, if you want to verify the SSL Certs
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| - **option.toProxy**: true/false, passes the absolute URL as the `path` (useful for proxying to proxies)
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| - **option.prependPath**: true/false, Default: true - specify whether you want to prepend the target's path to the proxy path
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| - **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).
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| - **option.localAddress** : Local interface string to bind for outgoing connections
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| - **option.changeOrigin**: true/false, Default: false - changes the origin of the host header to the target URL
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| - **option.preserveHeaderKeyCase**: true/false, Default: false - specify whether you want to keep letter case of response header key
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| - **option.auth** : Basic authentication i.e. 'user:password' to compute an Authorization header.
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| - **option.hostRewrite**: rewrites the location hostname on (301/302/307/308) redirects.
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| - **option.autoRewrite**: rewrites the location host/port on (301/302/307/308) redirects based on requested host/port. Default: false.
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| - **option.protocolRewrite**: rewrites the location protocol on (301/302/307/308) redirects to 'http' or 'https'. Default: null.
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| - **option.cookieDomainRewrite**: rewrites domain of `set-cookie` headers. Possible values:
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|   - `false` (default): disable cookie rewriting
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|   - String: new domain, for example `cookieDomainRewrite: "new.domain"`. To remove the domain, use `cookieDomainRewrite: ""`.
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|   - Object: mapping of domains to new domains, use `"*"` to match all domains.  
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|     For example keep one domain unchanged, rewrite one domain and remove other domains:
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|     ```json
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|     cookieDomainRewrite: {
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|       "unchanged.domain": "unchanged.domain",
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|       "old.domain": "new.domain",
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|       "*": ""
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|     }
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|     ```
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| - **option.cookiePathRewrite**: rewrites path of `set-cookie` headers. Possible values:
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|   - `false` (default): disable cookie rewriting
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|   - String: new path, for example `cookiePathRewrite: "/newPath/"`. To remove the path, use `cookiePathRewrite: ""`. To set path to root use `cookiePathRewrite: "/"`.
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|   - Object: mapping of paths to new paths, use `"*"` to match all paths.
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|     For example, to keep one path unchanged, rewrite one path and remove other paths:
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|     ```json
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|     cookiePathRewrite: {
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|       "/unchanged.path/": "/unchanged.path/",
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|       "/old.path/": "/new.path/",
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|       "*": ""
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|     }
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|     ```
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| - **option.headers**: object, adds [request headers](https://en.wikipedia.org/wiki/List_of_HTTP_header_fields#Request_fields). (Example: `{host:'www.example.org'}`)
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| - **option.proxyTimeout**: timeout (in millis) when proxy receives no response from target
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| - **option.timeout**: timeout (in millis) for incoming requests
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| - **option.followRedirects**: true/false, Default: false - specify whether you want to follow redirects
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| - **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
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| - **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:
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| 
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|   ```javascript
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|   'use strict';
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| 
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|   const streamify = require('stream-array');
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|   const HttpProxy = require('http-proxy');
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|   const proxy = new HttpProxy();
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| 
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|   module.exports = (req, res, next) => {
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|     proxy.web(
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|       req,
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|       res,
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|       {
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|         target: 'http://localhost:4003/',
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|         buffer: streamify(req.rawBody),
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|       },
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|       next
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|     );
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|   };
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|   ```
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| 
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| ## Shorthand
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| 
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| 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.
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| 
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| ```javascript
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| createProxyMiddleware('http://www.example.org:8000/api');
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| // createProxyMiddleware('/api', {target: 'http://www.example.org:8000'});
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| 
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| createProxyMiddleware('http://www.example.org:8000/api/books/*/**.json');
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| // createProxyMiddleware('/api/books/*/**.json', {target: 'http://www.example.org:8000'});
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| 
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| createProxyMiddleware('http://www.example.org:8000/api', { changeOrigin: true });
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| // createProxyMiddleware('/api', {target: 'http://www.example.org:8000', changeOrigin: true});
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| ```
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| 
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| ### app.use(path, proxy)
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| 
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| If you want to use the server's `app.use` `path` parameter to match requests;
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| Create and mount the proxy without the http-proxy-middleware `context` parameter:
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| 
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| ```javascript
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| app.use('/api', createProxyMiddleware({ target: 'http://www.example.org', changeOrigin: true }));
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| ```
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| 
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| `app.use` documentation:
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| 
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| - express: http://expressjs.com/en/4x/api.html#app.use
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| - connect: https://github.com/senchalabs/connect#mount-middleware
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| - polka: https://github.com/lukeed/polka#usebase-fn
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| 
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| ## WebSocket
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| 
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| ```javascript
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| // verbose api
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| createProxyMiddleware('/', { target: 'http://echo.websocket.org', ws: true });
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| 
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| // shorthand
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| createProxyMiddleware('http://echo.websocket.org', { ws: true });
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| 
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| // shorter shorthand
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| createProxyMiddleware('ws://echo.websocket.org');
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| ```
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| 
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| ### External WebSocket upgrade
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| 
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| 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.
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| 
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| ```javascript
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| const wsProxy = createProxyMiddleware('ws://echo.websocket.org', { changeOrigin: true });
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| 
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| const app = express();
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| app.use(wsProxy);
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| 
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| const server = app.listen(3000);
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| server.on('upgrade', wsProxy.upgrade); // <-- subscribe to http 'upgrade'
 | |
| ```
 | |
| 
 | |
| ## Intercept and manipulate requests
 | |
| 
 | |
| 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 and manipulate responses
 | |
| 
 | |
| 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](https://nodejs.org/api/buffer.html)) 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](https://github.com/chimurai/http-proxy-middleware/blob/master/recipes/response-interceptor.md#manipulate-image-response))
 | |
| 
 | |
| 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](https://github.com/chimurai/http-proxy-middleware/blob/master/recipes/response-interceptor.md#readme) for more examples.
 | |
| 
 | |
| ## 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))
 | |
| - Response Manipulation ([example source](https://github.com/chimurai/http-proxy-middleware/blob/master/examples/response-interceptor/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)
 | |
| - [fastify](https://www.npmjs.com/package/fastify)
 | |
| - [browser-sync](https://www.npmjs.com/package/browser-sync)
 | |
| - [lite-server](https://www.npmjs.com/package/lite-server)
 | |
| - [polka](https://github.com/lukeed/polka)
 | |
| - [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
 | |
| $ yarn
 | |
| 
 | |
| # linting
 | |
| $ yarn lint
 | |
| $ yarn lint:fix
 | |
| 
 | |
| # building (compile typescript to js)
 | |
| $ yarn build
 | |
| 
 | |
| # unit tests
 | |
| $ yarn test
 | |
| 
 | |
| # code coverage
 | |
| $ yarn cover
 | |
| 
 | |
| # check spelling mistakes
 | |
| $ yarn spellcheck
 | |
| ```
 | |
| 
 | |
| ## Changelog
 | |
| 
 | |
| - [View changelog](https://github.com/chimurai/http-proxy-middleware/blob/master/CHANGELOG.md)
 | |
| 
 | |
| ## License
 | |
| 
 | |
| The MIT License (MIT)
 | |
| 
 | |
| Copyright (c) 2015-2025 Steven Chim
 |