error messages

web/src/pages/add_logic/loader.rs

@@ -62,3 +62,19 @@ pub(crate) enum LoadError {
     Forbidden,
     Backend(String),
 }
+
+impl LoadError {
+    /// Hands the page load's failure to the one place that decides statuses.
+    /// `permission_key` names the message shown when the load was refused.
+    pub(crate) fn into_form_error(
+        self,
+        locale: crate::i18n::Locale,
+        permission_key: &str,
+    ) -> crate::ui::FormError {
+        match self {
+            Self::Unauthenticated => crate::ui::FormError::Unauthenticated,
+            Self::Forbidden => crate::ui::FormError::Forbidden(locale.lookup(permission_key)),
+            Self::Backend(message) => crate::ui::FormError::Unavailable(message),
+        }
+    }
+}

web/src/pages/add_logic/logic.rs

@@ -1,14 +1,15 @@
 use axum::{
     Form,
     extract::State,
-    http::{HeaderMap, StatusCode},
+    http::HeaderMap,
     response::{Html, IntoResponse, Redirect, Response},
 };
 
 use crate::{
     AppState,
-    {i18n::Locale, tr},
+    i18n::Locale,
     services::{authenticated_request, reject_cross_site},
+    ui::FormError,
 };
 
 use super::{
@@ -38,12 +39,7 @@ pub(crate) async fn create_logic(
     }
     let request = match form.into_request(Locale::from_headers(&headers)) {
         Ok(request) => request,
-        Err(message) => {
-            return render_loaded(
-                &headers,
-                load_page(state, &headers, submitted, Some(message)).await,
-            );
-        }
+        Err(message) => return reject(&headers, message),
     };
     let mut scripts = state.scripts;
     let request = match authenticated_request(&headers, request) {
@@ -57,34 +53,25 @@ pub(crate) async fn create_logic(
             &response.get_ref().warnings,
         ))
         .into_response(),
-        Err(error) => (
-            StatusCode::UNPROCESSABLE_ENTITY,
-            Html(ui::render_submission_error(
-                Locale::from_headers(&headers),
-                error.message(),
-            )),
-        )
-            .into_response(),
+        Err(error) => FormError::from_status(&error)
+            .into_response(Locale::from_headers(&headers), ui::render_submission_error),
     }
 }
 
+/// A submission this crate rejected before it reached the backend. Same
+/// response as a backend rejection: the user has to change something either
+/// way, and the form's `hx-target` is the status block in both cases.
+fn reject(headers: &HeaderMap, message: String) -> Response {
+    FormError::Rejected(message)
+        .into_response(Locale::from_headers(headers), ui::render_submission_error)
+}
+
 fn render_loaded(headers: &HeaderMap, result: Result<super::state::AddLogicPageState, LoadError>) -> Response {
     let locale = Locale::from_headers(headers);
     match result {
         Ok(page) => Html(ui::render_page(&page)).into_response(),
-        Err(LoadError::Unauthenticated) => Redirect::to("/login").into_response(),
-        Err(LoadError::Forbidden) => {
-            let message = tr!(locale, "add-logic-err-permission");
-            (
-                StatusCode::FORBIDDEN,
-                Html(ui::render_submission_error(locale, &message)),
-            )
-                .into_response()
-        }
-        Err(LoadError::Backend(message)) => (
-            StatusCode::BAD_GATEWAY,
-            Html(ui::render_submission_error(locale, &message)),
-        )
-            .into_response(),
+        Err(error) => error
+            .into_form_error(locale, "add-logic-err-permission")
+            .into_response(locale, ui::render_submission_error),
     }
 }