Assume I'm having a central method which adds a specific header to the http.ResponseWriter. I don't want to use a HandleFunc wrapper.
I wonder, whether I'd send in the ResponseWriter by reference. So, what would be correct:
addHeaders(&w)
or
addHeaders(w)
Asked differently:
func addHeaders(w *http.ResponseWriter) {...}
or
func addHeaders(w http.ResponseWriter) {...}
From my understanding, I'd say the first version would be correct, as I don't want to create a copy of ResponseWriter. But I haven't seen any code where ResponseWriter is passed by reference and wonder why.
Thanks!
http.ResponseWriter is an interface. You want to pass its value, since it internally contains a pointer to the actual Writer. You almost never want a pointer to an interface.
Look at what a standard handler func's signature is:
func(http.ResponseWriter, *http.Request)
Notice that ResponseWriter isn't a pointer.