@@ -15,6 +15,12 @@
 	"github.com/kevinpollet/nego"
 )
 
+var (
+	ErrReadingFile   = ihttp.NewError("Error reading file", http.StatusInternalServerError)
+	ErrNotFound      = ihttp.NewError("File not found", http.StatusNotFound)
+	ErrRenderFailure = ihttp.NewError("Error rendering template", http.StatusInternalServerError)
+)
+
 func (website *Website) ErrorHandler(err ihttp.Error, w http.ResponseWriter, r *http.Request) {
 	if strings.Contains(r.Header.Get("Accept"), "text/html") {
 		w.WriteHeader(err.StatusCode())
@@ -42,10 +48,10 @@ file, err := website.reader.GetFile(urlPath)
 	if err != nil {
 		website.log.Warn("Error reading file", "error", err)
 
-		return ihttp.InternalServerError("Error reading file", err)
+		return ErrReadingFile.WithCause(err)
 	}
 	if file == nil {
-		return ihttp.NotFound("File not found")
+		return ErrNotFound
 	}
 	analytics.WithTitle(r, file.Title)
 	w.Header().Add("ETag", file.Etag)
@@ -72,7 +78,7 @@ func (website *Website) Calendar(w http.ResponseWriter, r *http.Request) ihttp.Error {
 	analytics.WithTitle(r, "Calendar")
 	err := calendar.CalendarPage(*website.siteSettings, website.calendar).Render(w)
 	if err != nil {
-		return ihttp.InternalServerError("could not render calendar page", err)
+		return ErrRenderFailure.WithCause(err)
 	}
 
 	return nil