How to intercept the html generated by the web server before sending?

Question

Nginx

Hello.
This situation: there are 2 servers on Linux (one with Apache installed, the other with nginx) with a lot of terrible code in languages ​​and frameworks I don't know. Minor edits need to be made.
Please tell me, hypothetically, instead of long and boring picking the insides, is it possible to write a simple script (for example, in python) that would intercept the html generated by the server, find the necessary lines in it and replace it with others? And is it possible to make this script universal for both servers, that is, without preliminary config changes? And which way to look?

Answer 1

You can write a proxy server and put it between nginx and apache. There are 5-10 lines of code. I mean, you need an HTTP server that accepts a request, and sends everything that it has received to apache. The response from Apache changes and sends nginx.
You can google.
python proxy server

Answer 2

The best option is of course a module for nginx, but writing your own filter (in this case, you need it) will not be a trivial task.
Look at nginx.org/en/docs/http/ngx_http_sub_module.html and nginx.org/en/docs/http/ngx_http_addition_module.html if not enough, then dig towards nginx.org/en/docs/http/ngx_http_perl_module.html

Answer 3

habrahabr.ru/post/158393 wrote about this here.
There proxy_pass was in a foreign server, you will just have it in your own =)