multiple response.WriteHeader calls in really simple example?

Question

I have the most basic net/http program that I\'m using to learn the namespace in Go:

package main

import (
    \"fmt\"
    \"log\"
    \"net/http\"
)

func          


        

Answer 1

From the documentation:

// WriteHeader sends an HTTP response header with status code. 
// If WriteHeader is not called explicitly, the first call to Write  
// will trigger an implicit WriteHeader(http.StatusOK).

What is happening in your case is that you are launching go HandleIndex from the handler. The first handler finishes. The standard WriteHeader writes to the ResponseWriter. Then the go routine HandleIndex is launched and it also tries to write a header and write.

Just remove the go from HandleIndex and it will work.