Improve API client base URL validation

src/lib/apiClient.test.ts

@@ -0,0 +1,50 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { apiGet } from './apiClient';
+
+const originalEnv = process.env.NEXT_PUBLIC_API_BASE_URL;
+
+beforeEach(() => {
+  vi.restoreAllMocks();
+  process.env.NEXT_PUBLIC_API_BASE_URL = originalEnv;
+});
+
+afterEach(() => {
+  vi.resetModules();
+  vi.unstubAllGlobals();
+  process.env.NEXT_PUBLIC_API_BASE_URL = originalEnv;
+});
+
+describe('apiClient', () => {
+  it('throws when base URL is missing', async () => {
+    delete process.env.NEXT_PUBLIC_API_BASE_URL;
+
+    await expect(apiGet('/internal/agents')).rejects.toThrow('NEXT_PUBLIC_API_BASE_URL is not configured');
+  });
+
+  it('normalizes the request URL and returns JSON', async () => {
+    process.env.NEXT_PUBLIC_API_BASE_URL = 'https://api.example.com/';
+    const payload = { ok: true };
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => payload
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    const result = await apiGet('internal/agents');
+
+    expect(fetchMock).toHaveBeenCalledWith('https://api.example.com/internal/agents', {
+      method: 'GET',
+      headers: { 'content-type': 'application/json' }
+    });
+    expect(result).toEqual(payload);
+  });
+
+  it('wraps network failures with URL context', async () => {
+    process.env.NEXT_PUBLIC_API_BASE_URL = 'https://api.example.com';
+    vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('connection refused')));
+
+    await expect(apiGet('/internal/agents')).rejects.toThrow(
+      'Failed to reach API at https://api.example.com/internal/agents: connection refused'
+    );
+  });
+});

src/lib/apiClient.ts

@@ -1,15 +1,35 @@
+function buildApiUrl(path: string): string {
+  const baseUrl = process.env.NEXT_PUBLIC_API_BASE_URL;
+
+  if (!baseUrl) {
+    throw new Error('NEXT_PUBLIC_API_BASE_URL is not configured. Set it to your API endpoint.');
+  }
+
+  const normalizedBase = baseUrl.replace(/\/$/, '');
+  const normalizedPath = path.startsWith('/') ? path : `/${path}`;
+  return `${normalizedBase}${normalizedPath}`;
+}
+
 export async function apiGet<T>(path: string): Promise<T> {
-  const baseUrl = process.env.NEXT_PUBLIC_API_BASE_URL || 'http://localhost:3001';
+  const url = buildApiUrl(path);
-  const res = await fetch(`${baseUrl}${path}`, {
+
+  let res: Response;
+  try {
+    res = await fetch(url, {
       method: 'GET',
       headers: {
         'content-type': 'application/json'
       }
     });
+  } catch (error) {
+    const message = error instanceof Error ? error.message : 'Unknown error';
+    throw new Error(`Failed to reach API at ${url}: ${message}`);
+  }
 
   if (!res.ok) {
     const text = await res.text().catch(() => '');
-    throw new Error(`API error ${res.status}: ${text}`);
+    const body = text || res.statusText;
+    throw new Error(`API error ${res.status} from ${url}: ${body}`);
   }
 
   return res.json() as Promise<T>;