I do not know whether it's right to ask this question here. If not suitable, please tell me.
I use charles to monitor my Android mobile device's http traffic. It does works and now I want to do something when a reponse returns. For example, I visit www.google.com and the response returns then I want to save response text or do anything else.
Unfortunately I think there isn't such that option in CharlesProxy. The closest option you have, I think, is to save the session and then work on the saved file.
Check out the "Auto Save..." option under the "Tools" menu, it could help you.