Say what each action did in a one-line notice (closes #383)

Saving, deleting, activating or deactivating a webhook, entrypoint or target, and signing out, now land on their page with a one-line notice such as "Webhook deleted." or "Signed out.". The redirect carries a fixed code that maps to fixed text; an unknown code shows nothing, so nothing from the URL is ever echoed. One partial in the page layout shows the notice on every page, and replay and resubmit now use the same codes and partial. Error pages show no notice.

Model: opus-5-5

internal/handlers/delivery_replay.go

@@ -11,72 +11,37 @@ import (
 	"sneak.berlin/go/webhooker/internal/delivery"
 )
 
-// replayOutcomeParam is the query parameter the replay POST redirects
-// with and the event log page reads its banner from.
-const replayOutcomeParam = "replay"
-
-// replayOutcomeCode is the outcome of a replay POST. The redirect
-// carries one of these fixed codes rather than a message, so nothing a
-// client submits can reach the rendered page through it.
-type replayOutcomeCode string
-
+// The outcomes of a replay POST, as the notice codes its redirect
+// carries. noticeFor holds the line each one shows.
 const (
 	// replayQueued reports that a new delivery was created and handed
 	// to the delivery engine.
-	replayQueued replayOutcomeCode = "queued"
+	replayQueued noticeCode = "replay-queued"
 
 	// replayTargetDeleted reports a target that once existed and has
 	// since been deleted. Deletes are soft and deliveries carry no
 	// foreign key to the target row, so the history survives its
 	// target and this is the ordinary case for an old event.
-	replayTargetDeleted replayOutcomeCode = "target-deleted"
+	replayTargetDeleted noticeCode = "replay-target-deleted"
 
 	// replayTargetMissing reports a target id that names no row at
 	// all, deleted or otherwise.
-	replayTargetMissing replayOutcomeCode = "target-missing"
+	replayTargetMissing noticeCode = "replay-target-missing"
 
 	// replayTargetInactive reports a target the operator has
 	// deactivated. A deactivated target receives no new deliveries, so
 	// a replay to it would be a delivery they switched off.
-	replayTargetInactive replayOutcomeCode = "target-inactive"
+	replayTargetInactive noticeCode = "replay-target-inactive"
 
 	// replayNotTerminal reports a delivery the engine has not finished
 	// with.
-	replayNotTerminal replayOutcomeCode = "not-terminal"
+	replayNotTerminal noticeCode = "replay-not-terminal"
 
 	// replayInFlight reports that an earlier replay of this event to
 	// this target is still running.
-	replayInFlight replayOutcomeCode = "in-flight"
+	replayInFlight noticeCode = "replay-in-flight"
 )
 
-// replayOutcome returns the banner the event log page shows for an
-// outcome code, and whether the replay was queued. An unrecognised
-// code yields no banner.
-func replayOutcome(code string) (string, bool) {
-	switch replayOutcomeCode(code) {
-	case replayQueued:
-		return "Replay queued: a new delivery was created against " +
-			"the target's current configuration.", true
-	case replayTargetDeleted:
-		return "Not replayed: the target this delivery was for has " +
-			"been deleted. Recreate the target, then replay.", false
-	case replayTargetMissing:
-		return "Not replayed: the target this delivery was for no " +
-			"longer exists.", false
-	case replayTargetInactive:
-		return "Not replayed: the target this delivery was for is " +
-			"deactivated. Activate it, then replay.", false
-	case replayNotTerminal:
-		return "Not replayed: this delivery has not finished yet.",
-			false
-	case replayInFlight:
-		return "Not replayed: a delivery of this event to this " +
-			"target is already in flight.", false
-	default:
-		return "", false
-	}
-}
-
 // HandleDeliveryReplay re-sends a finished delivery's event to its
 // target.
 //
@@ -140,14 +105,14 @@ func (h *Handlers) replayDelivery(
 	}
 
 	if !original.Status.Terminal() {
-		h.finishReplay(w, r, webhook, replayNotTerminal)
+		redirectToEventLog(w, r, webhook, replayNotTerminal)
 
 		return
 	}
 
 	target, code := h.replayTarget(webhook.ID, original.TargetID)
 	if target == nil {
-		h.finishReplay(w, r, webhook, code)
+		redirectToEventLog(w, r, webhook, code)
 
 		return
 	}
@@ -200,7 +165,7 @@ func (h *Handlers) queueReplay(
 	}
 
 	if inFlight > 0 {
-		h.finishReplay(w, r, webhook, replayInFlight)
+		redirectToEventLog(w, r, webhook, replayInFlight)
 
 		return
 	}
@@ -238,7 +203,7 @@ func (h *Handlers) queueReplay(
 		"delivery_id", task.DeliveryID,
 	)
 
-	h.finishReplay(w, r, webhook, replayQueued)
+	redirectToEventLog(w, r, webhook, replayQueued)
 }
 
 // replayTarget loads the delivery's target as it stands now.
@@ -251,7 +216,7 @@ func (h *Handlers) queueReplay(
 // with the returned code saying why.
 func (h *Handlers) replayTarget(
 	webhookID, targetID string,
-) (*database.Target, replayOutcomeCode) {
+) (*database.Target, noticeCode) {
 	var target database.Target
 
 	err := h.db.DB().Unscoped().Where(
@@ -361,17 +326,16 @@ func replayBody(body string) *string {
 	return &body
 }
 
-// finishReplay redirects back to the event log the replay was
-// triggered from, carrying the outcome code the page turns into a
-// banner and the page number the form submitted.
-func (h *Handlers) finishReplay(
+// redirectToEventLog redirects a replay or resubmit back to the event
+// log it was triggered from, carrying the outcome as its notice and
+// the page number the form submitted.
+func redirectToEventLog(
 	w http.ResponseWriter,
 	r *http.Request,
 	webhook database.Webhook,
-	code replayOutcomeCode,
+	code noticeCode,
 ) {
-	dest := "/hook/" + webhook.ID + "/events?" +
-		replayOutcomeParam + "=" + string(code)
+	dest := withNotice("/hook/"+webhook.ID+"/events", code)
 
 	// The page is read from the form rather than the query string:
 	// this is a POST, and its query string is what logs and Referer