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Configurehttp2-proxy middleware with ease forkoa.

Based onhttp-proxy-middleware.

Proxy requests tohttp://www.example.org

varKoa=require('koa');varproxy=require('koa-http2-proxy');varapp=newKoa();// responseapp.use(proxy({target:'http://www.example.org'}));app.listen(3000);// http://localhost:3000/foo/bar -> http://www.example.org/foo/bar

💡Tip: Set the optionchangeOrigin totrue forname-based virtual hosted sites.

• Install
• Core concept
• Example
• Context matching
• Options
• Shorthand
  • app.use(path, proxy)
• WebSocket
  • External WebSocket upgrade
• Tests
• Changelog
• License

$npminstall--save-devkoa-http2-proxy

Proxy middleware configuration.

varproxy=require('koa-http2-proxy');varapiProxy=proxy('/api',{target:'http://www.example.org'});//                   \____/   \_____________________________///                     |                    |//                   context             options// 'apiProxy' is now ready to be used as middleware in a server.

• context: Determine which requests should be proxied to the target host.(more oncontext matching)
• options.target: target host to proxy to.(protocol + host)

(full list ofkoa-http2-proxy configuration options)

// shorthand syntax for the example above:varapiProxy=proxy('http://www.example.org/api');

More about theshorthand configuration.

// include dependenciesvarKoa=require('koa');varproxy=require('koa-http2-proxy');// proxy middleware optionsvaroptions={target:'http://www.example.org',// target hostws:true,// proxy websocketspathRewrite:{'^/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)varexampleProxy=proxy(options);// mount `exampleProxy` in web servervarapp=newKoa();app.use(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'spath parameter to mount the proxy or when you need more flexibility.

RFC 3986path 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 bymicromatch. Visitmicromatch orglob 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.

  /** *@return {Boolean} */varfilter=function(pathname,req){returnpathname.match('^/api')&&req.method==='GET';};varapiProxy=proxy(filter,{target:'http://www.example.org'});

• option.pathRewrite: object/function, rewrite target's url path. Object-keys will be used asRegExp to match paths.

  // rewrite pathpathRewrite:{'^/old/api' :'/new/api'}// remove pathpathRewrite:{'^/remove/api' :''}// add base pathpathRewrite:{'^/' :'/basepath/'}// custom rewritingpathRewrite:function(path,req){returnpath.replace('/api','/base/api')}

• option.router: object/function, re-targetoption.target for specific requests.

  // Use `host` and/or `path` 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 functionrouter: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.

  // simple replacefunctionlogProvider(provider){// replace the default console log provider.returnrequire('winston');}

  // verbose replacementfunctionlogProvider(provider){varlogger=new(require('winston')).Logger();varmyCustomProvider={log:logger.log,debug:logger.debug,info:logger.info,warn:logger.warn,error:logger.error};returnmyCustomProvider;}

• option.onError: function, subscribe to http-proxy'serror event for custom error handling.

  functiononError(err,ctx){ctx.response.status=500;ctx.response.body='Something went wrong. And we are reporting a custom error message.';}

• option.onProxyRes: function, subscribe to http-proxy'sproxyRes event.

  functiononProxyRes(proxyRes,ctx){proxyRes.headers['x-added']='foobar';// add new header to responsedeleteproxyRes.headers['x-removed'];// remove header from response}

• option.onProxyReq: function, subscribe to http-proxy'sproxyReq event.

  functiononProxyReq(proxyReq,ctx){// add custom header to requestproxyReq.setHeader('x-added','foobar');// or log the req}

• option.onUpgrade: function, called before upgrading a websocket connection.

  onUpgrade:asyncctx=>{// add session middleware to the websocket connection// see option.appawaitsession(ctx,()=>{});};

• option.app: koa app, used to generate a koa ctx to be used in onUpgrade. If left blank, a object containing onlyreq will be used as context

• option.headers: object, addsrequest headers. (Example:{host:'www.example.org'})

• option.target: url string to be parsed with the url module

• option.ws: true/false: if you want to proxy websockets

• option.xfwd: true/false, adds x-forward headers

• option.changeOrigin: true/false, Default: false - changes the origin of the host header to the target URL

• option.proxyTimeout: timeout (in millis) when proxy receives no response from target

• option.proxyName: Proxy name used for Via header

Use the shorthand syntax when verbose configuration is not needed. Thecontext andoption.target will be automatically configured when shorthand is used. Options can still be used if needed.

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');// proxy('/api', {target: 'http://www.example.org:8000'});

// verbose apiproxy('/',{target:'http://echo.websocket.org',ws:true});// shorthandproxy('http://echo.websocket.org',{ws:true});// shorter shorthandproxy('ws://echo.websocket.org');

In the previous WebSocket examples, http-proxy-middleware relies on a initial http request in order to listen to the httpupgrade event. If you need to proxy WebSockets without the initial http request, you can subscribe to the server's httpupgrade event manually.

varwsProxy=proxy('ws://echo.websocket.org');varapp=newKoa();app.use(wsProxy);varserver=app.listen(3000);server.on('upgrade',wsProxy.upgrade);// <-- subscribe to http 'upgrade'

Run the test suite:

# install dependencies$ yarn# linting$ yarn lint$ yarn lint:fix# building (compile typescript to js)$ yarn build# unit tests$ yarntest# code coverage$ yarn cover

• View changelog

The MIT License (MIT)

Copyright for portions of this project are held by Steven Chim, 2015-2019 as part ofhttp-proxy-middleware. All other copyright for this project are held by Ontola BV, 2019.