使用http.ServeFile更改HTTP代码

Question

I'm writing a server in Go, and I'm currently implementing error pages (404, 500, etc.) I have files which can be served for these errors, but if I use http.ServeFile then I get HTTP code 200 instead of the appropriate code.

Is there a way to change the status code, or do I need to rewrite http.ServeFile for this use case?

Answer 1

From reading the source I don't see any way to change the status code (other than the method failing which means you won't get your error page served). I think it's implied that if the files is served then it was an HTTP 200 which isn't entirely unreasonable.

I recommend reading the error page file into a string then using this method; https://golang.org/pkg/net/http/#Error

EDIT: That may actually not be specific enough for you even. It wants the error message as plain text so what I suggested is likely a misuse. In which case you're left with no useful abstractions to do what you want.

In response to comment, my personal preference would be something more along the line of;

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/sendstrailers", func(w http.ResponseWriter, req *http.Request) {
        resp := &http.Response{
            StatusCode: 404,
        }
        resp.Write(w)
    })
}

but you could also just use w.WriteHeader(http.StatusForbidden) or whatever if that's your preference. Whatever better suites you needs. My experience would be with preparing response object in a scope different than that of the mux so for that reason I think I prefer the bit above (it makes more sense than having helper methods return unstructured data you then write in to the responsewriter).