Question

Wrap a http.HandlerFunc closure

Sometimes you want to pass data to a http.HandlerFunc on initialization. This can easily be done by creating a closure of the http.HandlerFunc :

func MyHandler(database *sql.DB) http.Handler {
  return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
  // you now have access to the *sql.DB here
  })
}

Using gorilla/context for request-specific data

It is pretty often that we need to store and retrieve data that is specific to the current HTTP request. Use gorilla/context to map values and retrieve them later. It contains a global mutex on a map of request objects.

func MyHandler(w http.ResponseWriter, r *http.Request) {
  val := context.Get(r, "myKey")

  // returns ("bar", true)
  val, ok := context.GetOk(r, "myKey")
  // ...

}