How to set cookie to http response header? Why it doesn't work.

[hts0000]

How to set cookie to http response header? Why it doesn't work.

[hts0000]

I figured it out why the SetCookieMiddleware middleware can't set cookie.

Cause is http protoc unallow change body and header after first write, so excute http.SetCookie(w, &http.Cookie{}) after next.ServeHTTP(w, r) is meaningless.

[hts0000]

Finally, I solved my problem by referring to this. I hope it will be helpful to people who encounter the same confusion.