Using Nodejs for reverse proxy

In the actual engineering development, there will be a need for front-end separation.

In order to smooth the completion of front-end requests to the back-end of the individual services, a middleware to implement the request forwarding function, using Nginx can be implemented, here, using Nodejs to implement a reverse proxy server.

The actual front-end project background is node+express doing front-end routing, providing the base rendering and request forwarding of the page.

The backend uses Java springboot to develop multiple microservices (there is no use of spring cloud Eureka for service management and API orchestration), with each service IP consistent and port inconsistent.

Experimental environment: Nodejs+express Port is 3001, start a Java service, port is 8088, add a filter in Java, to output the requested address received, use postman around the client to initiate the request

@Override public void DoFilter (ServletRequest req, servletresponse Res, Filterchain chain) throws IOException, Servlete        xception {HttpServletRequest HttpRequest = (httpservletrequest) req; SYSTEM.OUT.PRINTLN ("Request address is" + ((httpservletrequest) req). Getrequesturi ());

First install "Http-proxy-middleware" middleware under the original Express project

NPM Install--save-dev Http-proxy-middleware

Quoting in Express's App.js

var proxy = require (' Http-proxy-middleware ');

Agent configuration According to the actual use situation

1. Forwarding all HTTP requests

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var options = {target: ' http://localhost:8088 ',//target host changeorigin:true,//requires a virtual host site};  var exampleproxy = proxy (options); Turn on the proxy function and load the configuration app.use ('/', exampleproxy);//Forwarding all requests for address '/'

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Test: Initiate any request to 127.0.0.1:3001 to see what happens to Java-side reception

Request URL	Service Access Input Results
127.0.0.1:3001/	Request Address Yes/
127.0.0.1:3001/test	The request address is/test
127.0.0.1:3002/test	Do not forward

2. Forwarding the request for the specified path

App.use ('/api ', exampleproxy);

Test:

Request URL	Service Access Input Results
127.0.0.1:3001/api/test	The request address is/api/test
127.0.0.1:3001/test	Do not forward
127.0.0.1:3001/api	The request address is/API
127.0.0.1:3002/test	Do not forward

3. Redirect the specified path rule

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var options = {        target:  ' http://localhost : 8088 ', //  target host         changeOrigin: true,                //  need a web hosting site          ws: true,                          //  Whether the agent websocket        pathrewrite: {              ' ^/api/old-path '  :  '/api/new-path ',                   ' ^/api/remove/path '  :   '/path ',                         ' ^/api/auth/login ': '/path '         }    }; Var exampleproxy = proxy (options);   //turn on proxy function and load configuration app.use ('/api ',  exampleproxy) ;//forwarding of all requests with address '/'

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Test:

Request URL	Service Access Input Results
127.0.0.1:3001/api/old-path	The request address is/api/new-path
127.0.0.1:3001/api/remove/path	The request address is/path
127.0.0.1:3001/api/auth/login	The request address is/path
127.0.0.1:3001/api/test	The request address is/api/test
127.0.0.1:3001/test	Do not forward

4. Route redirection for specified rules

It is simple to understand that, to join the current I started 2 and more Java services, the port is 8088,8089, but the front-end requests are pointing to 127.0.0.1:3001, the agent needs to be based on the actual front-end request, after resolving the path, distributed to different ports (8088, 8089) in the Java service

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var options = {target: ' http://localhost:8089 ',//Here The default forwarding target is 127.0.0.1:8089 router: {'/rest ': ' http://localhost:8088 ',//If the request path is/api/rest, redirect the request route of the URL ' 127.0.0.1:3001/api/8003 ': ' http://localhost:8003 ',/  /service This URL is redirected}};var exampleproxy = proxy (options); Turn on the proxy function and load the configuration app.use ('/api ', exampleproxy);//Forwarding all requests for address '/'

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Test:

TD rowspan= "1" colspan= "1" > 8089: Request address is/api

request URL    < /td>	service connection input result
127.0.0.1:3001/api/rest	8088: Request address is/api/rest
127.0.0.1:3002/api /rest	no response
127.0.0.1:3001/api	8088: Request address is/api
127.0.0.1:3001/api/8003	Forwarding failed (because we currently do not have a 8003 port service)
127.0.0.1:3001/api/rest/3232	8088: The request address is/api/rest/3232
127.0.0.1:3001/api

It is important to note that the proxy defaults to all requests under/API, forwarding to port 8089 services, exception handling for configurations in router, and tool rules forwarding to 8088 services or 8003 services

Summarize:

In the actual project, it is recommended to use a third case, through the "/api" and other wildcard characters to distinguish all requests to be forwarded and the normal HTTP page rendering requests. Then, according to the actual background service interface, we can configure different router rules.

Using Nodejs for reverse proxy