easy-pipe-proxy

• easy-pipe-proxy is a HTTP transparent proxy middleware, the goal of easy-pipe-proxy is to solve the browser cross-domain request.
• It is based on high performance of node.js native HTTP pipe

###install

npm install easy-pipe-proxy

example

connect or express

proxy layer

proxy.js

var app    = require('connect')();
var epp    = require('easy-pipe-proxy');

var proxyConfig = {
  host:'localhost',
  port:'3007',
  timeout:1000,
  router:'/api'
}

var proxy = new epp(proxyConfig);
//var proxy2 = new epp(proxyConfig2);

/*
	All requests from the client which req.url start withs '/api',will pipe proxy to 
	host: localhost, port:3007. 
*/

app.use(proxyConfig.router,proxy.pipe())

//app.use(proxyConfig2.router,proxy2.pipe())

app.use(function (err,req,res,next) {

  // err.eppRouter help you distinguish which proxy occurs error
  // if err.eppRouter or err.eppCode is undefined , 
  // it means nothing error occurs in easy-pipe-proxy
  
  console.log(err.code,err.eppCode,err.eppRouter);
  if (err.eppCode) {
  	// error occur in easy-pipe-proxy
	res.statusCode = err.eppCode
  	res.end(err.message);  	
  }
  
  // other errors
  //...
})

app.listen(3006);

back-end service layer

service.js

var app    = require('connect')();
/*
	if A HTTP request from client is 'localhost:3006/api/ok' via any
	method (GET/POST),
	easy-pipe-proxy will auto pipe this request to 'localhost:3007/ok',and then pipe
	the proxy response to client;
*/

app.use('/ok',(req,res,next) => {
  res.statusCode = 200;
  res.end('hello world');
})

/*
	if A HTTP request from client is 'localhost:3006/api/pending' via any
	method (GET/POST),
	easy-pipe-proxy will auto pipe this request to 'localhost:3007/pending',and then pipe
	the proxy response to client;
*/

app.use('/pending',(req,res,next) => {

})

app.listen(3007);

start example

node proxy.js
node service.js

vist http://localhost:3006/api/ok

In this example, http://localhost:3007/ok and http://localhost:3006/api/ok will get the same result.

proxyConfig

• host [string]: The back-end service IP or domian
• port [string/number]: The back-end service port
• timeout [number]: default 2 min. pipe-proxy will abort proxy after timeout (mses),and it will cause a timeout error.
• router [string]: connect's/express's router, this router controls requests which come from the client will be proxy by easy-pipe-proxy.

errorCode

if some error occurs in easy-pipe-proxy, 
easy-pipe-proxy will append eppCode (easy-pipe-proxy Code) and eppRouter (easy-pipe-proxy Router) to the error object . 
Connect/express error middleware will capture this error object.  

like:
  vist http://localhost:3006/api/pending
  
  app.use(function (err,req,res,next) {
    console.log(err.eppCode,err.eppRouter);
  })

but if nothing error occurs in easy-pipe-proxy ,the eppCode and eppRouter attribute will be undefined.
  

eppCode

• 408, proxy timeout
• 500, proxy error

eppRouter

• config.router, eg: '/api', config.router

proxy header

• in order to solve some security problems, easy-pipe-proxy will change req.headers.host (which comes from client ) to config.host + ':' + config.port

• eg: if we pipe proxy xxx.xxx.xxx.xxx:3006 to xxx.xxx.xxx.xxx:3007 , and then we vist http://xxx.xxx.xxx.xxx:3006 in browser. easy-pipe-proxy receives req.headers.host from client should be 'xxx.xxx.xxx.xxx:3006' , easy-pipe-proxy will change req.headers.host to 'xxx.xxx.xxx.xxx:3007' and save 'xxx.xxx.xxx.xxx:3006' to 'X-Proxy-Host' as a property of req.headers

code:

	req.headers['X-Proxy-Host'] = req.headers.host;
	req.headers.host = config.host ;
	
	...
	
	if (config.port) {
      option.port = config.port;
      req.headers.host =  config.host + ':' + config.port;
    }