fix: show more user friendly error page for authorize interaction failures

frontend/src/routes/interaction/+page.ts

@@ -1,16 +1,23 @@
 import OidcService from '$lib/services/oidc-service';
-import { error } from '@sveltejs/kit';
+import { getAxiosErrorMessage } from '$lib/utils/error-util';
+import { redirect } from '@sveltejs/kit';
 import type { PageLoad } from './$types';
 
 export const load: PageLoad = async ({ url }) => {
 	const interactionSessionId = url.searchParams.get('interaction');
 	if (!interactionSessionId) {
-		error(400, 'Missing authorize interaction');
+		return redirectToError('Missing authorize interaction');
 	}
 
 	const oidcService = new OidcService();
-	const interactionSession = await oidcService.getAuthorizeInteraction(interactionSessionId);
+	const interactionSession = await oidcService
+		.getAuthorizeInteraction(interactionSessionId)
+		.catch((e) => redirectToError(getAxiosErrorMessage(e)));
 	return {
 		interactionSession
 	};
 };
+
+function redirectToError(errorMessage: string): never {
+	redirect(302, `/interaction/error?${new URLSearchParams({ error: errorMessage }).toString()}`);
+}

tests/specs/oidc.spec.ts

@@ -193,6 +193,21 @@ test('Authorize new client shows Pocket ID error when user group not allowed', a
 	).toBeVisible();
 });
 
+test('Unknown authorize interaction shows the interaction error page', async ({
+	page
+}, testInfo) => {
+	const relyingPartyUrl = new URL('/client-return', testInfo.project.use.baseURL).toString();
+	await page.goto(`/interaction?interaction=${crypto.randomUUID()}`, { referer: relyingPartyUrl });
+
+	await expect(page).toHaveURL(/\/interaction\/error\?error=/);
+	await expect(page.getByRole('heading', { name: 'Error' })).toBeVisible();
+	await expect(page.getByText('OIDC interaction not found or expired')).toBeVisible();
+	await expect(page.getByRole('link', { name: 'Go back' })).toHaveAttribute(
+		'href',
+		relyingPartyUrl
+	);
+});
+
 function createUrlParams(oidcClient: { id: string; callbackUrl: string }) {
 	return new URLSearchParams({
 		client_id: oidcClient.id,