x-proxy

Build Status](https://travis-ci.org/x-component/x-proxy)

• ./proxy.js

./proxy.js

• url

url

x-proxy

This module provides helper functions to map urls from an external client representations to urls as used bay a backend server. It also supports the reverse mapping back from urls of the backend server to external client urls.

The following diagram depicts a proxy mounting the backend server at the mount point '/xyz'

               +---------+        +----------------------------------+
  client ----->|  proxy  |------->| target backend server            |
               |  mount: |        | url:                             |
               |  '/xyz' |        | http://server:8080/target/path   |
               +---------+        +----------------------------------+

The extenral url /xyz/a?b=c seen by a client of the proxy, should thus be mapped to http://server:8080/target/path/a?b=c

Note: the external url representation takes care about x-forwarded-host headers etc.

  var proxy = require('x-proxy');

  var mount = '/xyz';
  var prx = req.proxy = proxy(req,{url:'http://server:8080/target/path'},mount);
  // prx now provide mapping functions within the context of this request and the given target url

** request / backend specific helpers: **

prx.internal( url )

test if an url is part of the proxy backend server, thus an internal location, or is just link to some external location (false) for internal locations a object is returned : {secure_switch:false} or {secure_switch:true}. secure_switch indicates if it is an internal location but the protocoll is changed. p.e. to jump to a https version of the location

prx.url( url )

maps an url with mount of the server to an url in terms of the backend server

prx.reverse( url, with_http_server_port )

maps an url of the backen server to an url for the client. Use with_http_server_port=true in case you need an absolute url. p.e. for lcoation headers.

prx.relativize( url )

transforms an (absolute) backend server url to a extrnal valid relative url. This allows to rewrite html content to relattive urls, such they stay valid in a chain of proxies.

prx.resolve( relative_url , with_http_server_port )

relsolve a releative url to an external absolute url. Use with_http_server_port=true in case you need an absolute url with server and port.

** global helpers: **

proxy.relativize( base, path )

for a prefix and a an absolute path return a relative path: p.e. base:'/a/b/c/d', path:'/a/b/e', result: '../e'

proxy.absolutize( req, relative_path, with_http_server_port )

return an absolute url for this request, optionally with protocol, server and port.

proxy.externalize( req, relative_url )

create an absolute url suitable for a client browser, thus using host and x-forwarded host headerss

proxy.internalize( req, relative_url )

create an absolute url suitable for this server internally, NOT using x-forwarded-host etc.

proxy.secure( req )

return an absolute secure version of the current request url for a client