🤖 flash

amadan.net/rastrillo/rastrillo/flash

One-shot notice messages carried in a cookie and cleared once read.

A flash is display state, not a record. Losing one to a cleared cookie costs a notice, not data, which is what makes a cookie the right place for it instead of a database table with a lifecycle to manage.

Flash

type Flash struct {
	Kind    string
	Message string
}

Kind is your own vocabulary — "notice", "error" — and your layout decides how each renders.

Set

func Set(w http.ResponseWriter, kind, message string)

Writes the cookie. Call it immediately before the redirect that will show it:

flash.Set(w, "notice", "Note created.")
http.Redirect(w, r, "/notes/"+id, http.StatusSeeOther)

Take

func Take(w http.ResponseWriter, r *http.Request) (Flash, bool)

Reads and clears in one call, which is the one-shot part. Call it once per page from your render helper and let the layout render what it returns; call it twice in one request and the second caller gets nothing.

A missing or unparseable cookie answers false with a zero Flash instead of an error. There is nothing useful an app could do about a corrupt notice cookie except ignore it.

Read this page as markdown — exact, unstyled, and cheap for an agent to fetch.