Check subscriber existence by UUID on public pages

handlers.go

@@ -97,13 +97,13 @@ func registerHandlers(e *echo.Echo) {
 	e.DELETE("/api/templates/:id", handleDeleteTemplate)
 
 	// Subscriber facing views.
-	e.GET("/subscription/:campUUID/:subUUID", validateUUID(handleSubscriptionPage,
+	e.GET("/subscription/:campUUID/:subUUID", validateUUID(subscriberExists(handleSubscriptionPage),
 		"campUUID", "subUUID"))
-	e.POST("/subscription/:campUUID/:subUUID", validateUUID(handleSubscriptionPage,
+	e.POST("/subscription/:campUUID/:subUUID", validateUUID(subscriberExists(handleSubscriptionPage),
 		"campUUID", "subUUID"))
-	e.POST("/subscription/export/:subUUID", validateUUID(handleSelfExportSubscriberData,
+	e.POST("/subscription/export/:subUUID", validateUUID(subscriberExists(handleSelfExportSubscriberData),
 		"subUUID"))
-	e.POST("/subscription/wipe/:subUUID", validateUUID(handleWipeSubscriberData,
+	e.POST("/subscription/wipe/:subUUID", validateUUID(subscriberExists(handleWipeSubscriberData),
 		"subUUID"))
 	e.GET("/link/:linkUUID/:campUUID/:subUUID", validateUUID(handleLinkRedirect,
 		"linkUUID", "campUUID", "subUUID"))
@@ -136,7 +136,7 @@ func handleIndexPage(c echo.Context) error {
 	return c.String(http.StatusOK, string(b))
 }
 
-// validateUUID validates the UUID string format for a given set of params.
+// validateUUID middleware validates the UUID string format for a given set of params.
 func validateUUID(next echo.HandlerFunc, params ...string) echo.HandlerFunc {
 	return func(c echo.Context) error {
 		for _, p := range params {
@@ -150,6 +150,32 @@ func validateUUID(next echo.HandlerFunc, params ...string) echo.HandlerFunc {
 	}
 }
 
+// subscriberExists middleware checks if a subscriber exists given the UUID
+// param in a request.
+func subscriberExists(next echo.HandlerFunc, params ...string) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		var (
+			app     = c.Get("app").(*App)
+			subUUID = c.Param("subUUID")
+		)
+
+		var exists bool
+		if err := app.Queries.SubscriberExists.Get(&exists, 0, subUUID); err != nil {
+			app.Logger.Printf("error checking subscriber existence: %v", err)
+			return c.Render(http.StatusInternalServerError, "message",
+				makeMsgTpl("Error", "",
+					`Error processing request. Please retry.`))
+		}
+
+		if !exists {
+			return c.Render(http.StatusBadRequest, "message",
+				makeMsgTpl("Not found", "",
+					`Subscription not found.`))
+		}
+		return next(c)
+	}
+}
+
 // getPagination takes form values and extracts pagination values from it.
 func getPagination(q url.Values) pagination {
 	var (