来自代码的反向代理和HTTP请求

Question

I'm trying to figure out what is the "proper" way to make HTTP requests programatically from web application code when you don't know if you are or are not running behind reverse proxy (eg HTTPD).

• Web application runs on root "/" context on web server
• Proxy runs with context "/proxy" that proxies this that web server

Accessing index.html from browser should be requested via /proxy/index.html. But what if there is some code in the web application (eg myscript.js) that sends HTTP request programatically (eg xhr.open("???/resource").

And here comes the problem because the code sends this HTTP request to /resource instead of sending it to /proxy/resource.

In other words, the code of web application (that runs in the browser) does not know if there is any or there isn't a proxy. Keep in mind that application can run behind proxy but there may not be any proxy at all. I have in mind 3 solutions:

1) Web application resolves context (eg /proxy) automatically by parsing it from the current window.location.path and send xhr according to it

2) Enhance web application to require some additional configuration of proxy from user and it appends the context if it is set

3) Configure proxy somehow to also resend non-proxy like URLs to web server 1:1 (eg /proxy -> webserver/, / -> webserver/)

Which one is "the proper" one or there are any other options?

Answer 1

Backend web applications should not be aware if there is proxy or not above or before them. They should ideally live in their own context path, eg. /application/ and if they need to send redirects do so without using hostnames or url schemes in it, just URL-Path /application/*

Then ideally you can do easy reverse proxy directives according to your number 3 scenario:

ProxyPass /XXX/ http://backend/application/
ProxyPassReverse /XXX/ http://backend/application/