Making golang Gorilla CORS handler work

Question

I have fairly simple setup here as described in the code below. But I am not able to get the CORS to work. I keep getting this error:

XML

Answer 1

I realize this is an old issue but nonetheless it took me 30min to get this right.

handler = handlers.CORS(
    // handlers.AllowedMethods([]string{"GET", "POST", "PUT"}),
    handlers.AllowedHeaders([]string{"Accept", "Accept-Language", "Content-Type", "Content-Language", "Origin"}),
    // handlers.AllowedOrigins([]string{"*"}),
)(handler)

Things to note:

• AllowedMethods does NOT need to explicitly include OPTIONS, this is part of the CORS handler
• AllowedHeaders need to be explicitly mentioned, * is not a valid wildcard. Typical ajax libraries will send Content-Type when requesting something like application/json, so add that as well.
• * is the default for AllowedOrigin