fix(bunny): read the CDN host from runtime config so Docker images can play video

NEXT_PUBLIC_BUNNY_CDN_URL is inlined into the client bundle at build time, and
the published image is built by CI without it, so the browser had no host to
build a playlist URL from no matter what the operator set in .env.docker. The
player read the empty URL as a stream that had not finished encoding and sat on
'Video Is Processing', retrying forever.

The server knows the value on every request, so the root layout now serialises
the public settings into a JSON script tag and the browser reads them from
there, falling back to the build-time variable for source builds. The
direct-download allow list came through the same broken path and moves with it.

Closes #60

tests/component/hooks/use-download-actions.test.ts

@@ -125,6 +125,9 @@ function urlsFetched(): string[] {
 }
 
 beforeEach(() => {
+  // The runtime resolver reads BUNNY_CDN_URL first, so pin it rather than
+  // inheriting the value a developer has in .env.
+  vi.stubEnv('BUNNY_CDN_URL', undefined);
   vi.stubEnv('NEXT_PUBLIC_BUNNY_CDN_URL', `https://${BUNNY_HOST}`);
   vi.stubEnv('NEXT_PUBLIC_DIRECT_DOWNLOAD_ALLOWED_HOSTS', ALLOWED_DIRECT_HOST);
   clicked = [];

tests/component/hooks/use-version-actions.test.ts

@@ -173,6 +173,9 @@ function makeFile(name = 'my clip.mp4') {
 beforeEach(() => {
   tusUploads.length = 0;
   tusFailure = null;
+  // The runtime resolver reads BUNNY_CDN_URL first, so pin it rather than
+  // inheriting the value a developer has in .env.
+  vi.stubEnv('BUNNY_CDN_URL', undefined);
   vi.stubEnv('NEXT_PUBLIC_BUNNY_CDN_URL', 'https://cdn.example.test');
   fetchMock = vi.fn((url: string) => {
     if (url === BUNNY_INIT_URL) {

tests/component/runtime-public-config.test.ts

@@ -0,0 +1,134 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { resolvePublicBunnyCdnHostname } from '@/lib/bunny-cdn';
+import {
+  buildRuntimePublicConfig,
+  readRuntimePublicConfig,
+  resolvePublicDirectDownloadAllowedHosts,
+  RUNTIME_PUBLIC_CONFIG_ELEMENT_ID,
+} from '@/lib/runtime-public-config';
+
+/**
+ * These run in jsdom because that is the only place the bug shows: on the server
+ * the environment is readable at request time, in the browser it is whatever was
+ * inlined when the bundle was built, which for the published Docker image is
+ * nothing.
+ */
+function injectConfig(payload: string): void {
+  const element = document.createElement('script');
+  element.id = RUNTIME_PUBLIC_CONFIG_ELEMENT_ID;
+  element.type = 'application/json';
+  element.textContent = payload;
+  document.body.appendChild(element);
+}
+
+beforeEach(() => {
+  vi.stubEnv('BUNNY_CDN_URL', undefined);
+  vi.stubEnv('NEXT_PUBLIC_BUNNY_CDN_URL', undefined);
+  vi.stubEnv('NEXT_PUBLIC_DIRECT_DOWNLOAD_ALLOWED_HOSTS', undefined);
+});
+
+afterEach(() => {
+  vi.unstubAllEnvs();
+  document.getElementById(RUNTIME_PUBLIC_CONFIG_ELEMENT_ID)?.remove();
+});
+
+describe('buildRuntimePublicConfig', () => {
+  it('prefers the server variable over the public one', () => {
+    vi.stubEnv('BUNNY_CDN_URL', 'https://server.b-cdn.net');
+    vi.stubEnv('NEXT_PUBLIC_BUNNY_CDN_URL', 'https://public.b-cdn.net');
+
+    expect(buildRuntimePublicConfig().bunnyCdnUrl).toBe('https://server.b-cdn.net');
+  });
+
+  it('emits empty strings rather than undefined when nothing is configured', () => {
+    expect(buildRuntimePublicConfig()).toEqual({
+      bunnyCdnUrl: '',
+      directDownloadAllowedHosts: '',
+    });
+  });
+});
+
+describe('readRuntimePublicConfig', () => {
+  it('returns null when the page carries no config', () => {
+    expect(readRuntimePublicConfig()).toBeNull();
+  });
+
+  it('returns null for a payload that is not valid JSON', () => {
+    injectConfig('{ not json');
+
+    expect(readRuntimePublicConfig()).toBeNull();
+  });
+
+  it('coerces missing or non-string fields to empty strings', () => {
+    injectConfig(JSON.stringify({ bunnyCdnUrl: 42 }));
+
+    expect(readRuntimePublicConfig()).toEqual({
+      bunnyCdnUrl: '',
+      directDownloadAllowedHosts: '',
+    });
+  });
+});
+
+describe('resolvePublicBunnyCdnHostname in the browser', () => {
+  it('uses the injected hostname when the build-time variable is empty', () => {
+    // The published Docker image, where the operator configured BUNNY_CDN_URL at
+    // runtime and the bundle was built without it.
+    injectConfig(JSON.stringify({ bunnyCdnUrl: 'https://vz-runtime.b-cdn.net' }));
+
+    expect(resolvePublicBunnyCdnHostname()).toBe('vz-runtime.b-cdn.net');
+  });
+
+  it('prefers the injected hostname over the one inlined at build time', () => {
+    vi.stubEnv('NEXT_PUBLIC_BUNNY_CDN_URL', 'https://vz-build.b-cdn.net');
+    injectConfig(JSON.stringify({ bunnyCdnUrl: 'https://vz-runtime.b-cdn.net' }));
+
+    expect(resolvePublicBunnyCdnHostname()).toBe('vz-runtime.b-cdn.net');
+  });
+
+  it('falls back to the build-time variable when the injected value is empty', () => {
+    vi.stubEnv('NEXT_PUBLIC_BUNNY_CDN_URL', 'https://vz-build.b-cdn.net');
+    injectConfig(JSON.stringify({ bunnyCdnUrl: '' }));
+
+    expect(resolvePublicBunnyCdnHostname()).toBe('vz-build.b-cdn.net');
+  });
+
+  it('returns null when neither source is configured', () => {
+    injectConfig(JSON.stringify({ bunnyCdnUrl: '' }));
+
+    expect(resolvePublicBunnyCdnHostname()).toBeNull();
+  });
+});
+
+describe('resolvePublicDirectDownloadAllowedHosts', () => {
+  it('splits, trims and lowercases the injected list', () => {
+    injectConfig(
+      JSON.stringify({ directDownloadAllowedHosts: ' Files.Example.com , cdn.example.com ,, ' })
+    );
+
+    expect(resolvePublicDirectDownloadAllowedHosts()).toEqual([
+      'files.example.com',
+      'cdn.example.com',
+    ]);
+  });
+
+  it('falls back to the build-time variable when no config is injected', () => {
+    vi.stubEnv('NEXT_PUBLIC_DIRECT_DOWNLOAD_ALLOWED_HOSTS', 'files.example.com');
+
+    expect(resolvePublicDirectDownloadAllowedHosts()).toEqual(['files.example.com']);
+  });
+
+  it('keeps the build-time list when the injected one is empty', () => {
+    // An empty injected value means nothing was configured on this deployment, so
+    // it must not narrow a source build that already had a list.
+    vi.stubEnv('NEXT_PUBLIC_DIRECT_DOWNLOAD_ALLOWED_HOSTS', 'files.example.com');
+    injectConfig(JSON.stringify({ directDownloadAllowedHosts: '' }));
+
+    expect(resolvePublicDirectDownloadAllowedHosts()).toEqual(['files.example.com']);
+  });
+
+  it('returns an empty list when neither source is configured', () => {
+    injectConfig(JSON.stringify({ directDownloadAllowedHosts: '' }));
+
+    expect(resolvePublicDirectDownloadAllowedHosts()).toEqual([]);
+  });
+});