There’re 2 conditions in my question. In the links the solutions described are partial, though. A part of a part. That is, “how to identify a keyword”, “how to redirect if …”.

But how to actually put them all together? For instance, how to merge “if a keyword then redirect via a pre-specified, random sub-proxy”? How to them add into all that “otherwise, use no proxy”?

1. client -> HaProxy -> if keyword --> sub-proxy (random) -> website
2. client -> HaProxy -> if no keyword --> website

Got it