Squid + ICAP: how to do it?

Question

CMS

Hi all!
There is a task: to configure Squid in such a way that for all packets from a certain host and port 80, some text is added to the content. For example, if:

1. host=google.com
   
2. port=80
   
3. Request = "/"
   

then in this case, at the very beginning of the response, the magic phrase “ololo” appears (don’t care that no one will see it, that’s not what we are talking about now).
I understand that you need to use ICAP because that's what it seems to be designed for. I understand the need to use Squid (I have 3.1). But I don't understand how:

1. Start an ICAP server - you can even build it into a squid
   
2. Configure it the way I need, by editing configs or writing code
   

Who thinks what? The platform, of course, is Linux (AMD64 if that matters). Other solutions to this problem are welcome, Squid is optional.

Answer 1

I remember that there is an ICAP client in the squid .
And any modern IPS-ka, for example, solves your problem. We write our own signature, detect the necessary packages and modify them.