I am new to selenium.
I found selenium would not use my local firefox browser. Seems it create a fresh one with no plugin.
But I want do something with plugin on, such as: modify request headers, aotuproxy. I only found setting headers example in java.  Though proxy can be set by using webdriver.FirefoxProfile().set_preference('network.proxy.http',....,  it is not so sweet to fit my aim.
So I think it would be very nice to make selenium use my firefox. But I can not figure it out.
Selenium cannot connect to an existing browser. It can only launch new instances.
How can I make Selenium use my firefox (not create a fresh one)