Fixed API_URL handling.

README.md

@@ -47,7 +47,7 @@ DATABASE_URL=connection-url
 ```
 
 Optional: set `API_URL` to change the base URL used by internal UI API calls.
-Relative paths are served under `BASE_PATH`; absolute URLs are called directly by the browser.
+Relative paths are served under `BASE_PATH`; absolute URLs are proxied through the local `/api` route.
 For example, `API_URL=/internal-api` or `API_URL=https://api.example.com/api`.
 
 The connection URL format:

src/lib/api-url.test.ts

@@ -0,0 +1,37 @@
+import { describe, expect, test } from 'vitest';
+import { getApiUrl } from './api-url';
+
+describe('getApiUrl', () => {
+  test('uses the local api path when API_URL is absolute', () => {
+    expect(
+      getApiUrl('/websites', {
+        apiUrl: 'https://gateway-eu.umami.dev/api',
+        basePath: '/analytics',
+      }),
+    ).toBe('/analytics/api/websites');
+  });
+
+  test('uses a relative API_URL under the base path', () => {
+    expect(
+      getApiUrl('/websites', {
+        apiUrl: '/internal-api',
+        basePath: '/analytics',
+      }),
+    ).toBe('/analytics/internal-api/websites');
+  });
+
+  test('keeps app routes on the local api path', () => {
+    expect(
+      getApiUrl('/auth/verify', {
+        apiUrl: '/internal-api',
+        basePath: '/analytics',
+      }),
+    ).toBe('/analytics/api/auth/verify');
+  });
+
+  test('returns absolute input urls unchanged', () => {
+    expect(getApiUrl('https://example.com/api/websites')).toBe(
+      'https://example.com/api/websites',
+    );
+  });
+});

src/lib/api-url.ts

@@ -39,12 +39,8 @@ export function getApiUrl(url: string, options: ApiUrlOptions = {}) {
   }
 
   const { apiUrl = process.env.apiUrl || '', basePath = process.env.basePath || '' } = options;
-  const useApiUrl = apiUrl && !isAppRoute(url);
-  const baseUrl = useApiUrl
-    ? isAbsoluteUrl(apiUrl)
-      ? apiUrl
-      : joinPath(basePath, apiUrl)
-    : joinPath(basePath, '/api');
+  const useApiUrl = apiUrl && !isAbsoluteUrl(apiUrl) && !isAppRoute(url);
+  const baseUrl = useApiUrl ? joinPath(basePath, apiUrl) : joinPath(basePath, '/api');
 
   return joinPath(baseUrl, url);
 }