fix(cctv): add Taiwan Highway Bureau fallback

src/data/cctvProxy.test.mjs

@@ -313,3 +313,159 @@ test('CCTV upstream frame fetch accepts only raster image types and sends their
     assert.equal(state.cancelled, true, `${contentType}: body cancelled`);
   }
 });
+
+function multipartResponse(contentType, chunks, { onCancel = () => {} } = {}) {
+  let nextChunk = 0;
+  const body = new ReadableStream(
+    {
+      pull(controller) {
+        if (nextChunk >= chunks.length) {
+          controller.close();
+          return;
+        }
+        controller.enqueue(chunks[nextChunk++]);
+      },
+      cancel() {
+        onCancel();
+      },
+    },
+    { highWaterMark: 0 },
+  );
+  return new Response(body, {
+    status: 200,
+    headers: { 'Content-Type': contentType },
+  });
+}
+
+function jpegPart(boundary, body, contentType = 'image/jpeg', length = body.length) {
+  return Buffer.concat([
+    Buffer.from(
+      '--' +
+        boundary +
+        '\r\nContent-Type: ' +
+        contentType +
+        '\r\nContent-Length: ' +
+        length +
+        '\r\n\r\n',
+    ),
+    body,
+    Buffer.from('\r\n'),
+  ]);
+}
+
+test('CCTV upstream frame fetch extracts only the first JPEG from MJPEG', async () => {
+  const boundary = 'DIGIEVER';
+  const first = Buffer.from([0xff, 0xd8, 0x11, 0x22, 0xff, 0xd9]);
+  const second = Buffer.from([0xff, 0xd8, 0x33, 0x44, 0xff, 0xd9]);
+  for (const type of [
+    'multipart/x-mixed-replace; boundary=DIGIEVER',
+    'multipart/x-mixed-replace; boundary="DIGIEVER"',
+  ]) {
+    let cancelled = false;
+    const result = await fetchCctvImageFromUpstream(
+      'https://cctv-ss02.thb.gov.tw/T62-9K+020',
+      {
+        maxBytes: 1024,
+        fetchImpl: async () =>
+          multipartResponse(
+            type,
+            [
+              jpegPart(boundary, first),
+              jpegPart(boundary, second),
+              Buffer.from('--' + boundary + '--\r\n'),
+            ],
+            { onCancel: () => { cancelled = true; } },
+          ),
+      },
+    );
+    assert.equal(result?.contentType, 'image/jpeg', type);
+    assert.deepEqual(result?.body, first, type);
+    assert.equal(cancelled, true, type);
+  }
+});
+
+test('CCTV upstream frame fetch rejects malformed and non-JPEG MJPEG parts', async () => {
+  const jpeg = Buffer.from([0xff, 0xd8, 0x01, 0x02, 0xff, 0xd9]);
+  for (const [type, chunks] of [
+    ['multipart/x-mixed-replace', []],
+    [
+      'multipart/x-mixed-replace; boundary=DIGIEVER',
+      [jpegPart('DIGIEVER', jpeg, 'image/png')],
+    ],
+  ]) {
+    let cancelled = false;
+    const result = await fetchCctvImageFromUpstream(
+      'https://cctv-ss02.thb.gov.tw/T62-9K+020',
+      {
+        fetchImpl: async () =>
+          multipartResponse(type, chunks, { onCancel: () => { cancelled = true; } }),
+      },
+    );
+    assert.equal(result, null, type);
+    assert.equal(cancelled, true, type);
+  }
+});
+
+test('CCTV upstream frame fetch rejects truncated or oversized MJPEG parts', async () => {
+  const boundary = 'DIGIEVER';
+  const full = Buffer.from([0xff, 0xd8, 0x01, 0x02, 0xff, 0xd9]);
+  const truncated = Buffer.from([0xff, 0xd8, 0x01, 0x02]);
+  for (const [chunks, maxBytes] of [
+    [jpegPart(boundary, truncated, 'image/jpeg', full.length), 1024],
+    [jpegPart(boundary, full), 5],
+  ]) {
+    let cancelled = false;
+    const result = await fetchCctvImageFromUpstream(
+      'https://cctv-ss02.thb.gov.tw/T62-9K+020',
+      {
+        maxBytes,
+        fetchImpl: async () =>
+          multipartResponse(
+            'multipart/x-mixed-replace; boundary=' + boundary,
+            [chunks],
+            { onCancel: () => { cancelled = true; } },
+          ),
+      },
+    );
+    assert.equal(result, null);
+    assert.equal(cancelled, true);
+  }
+});
+
+test('CCTV upstream frame fetch does not cross into a later part when the first JPEG is truncated', async () => {
+  const boundary = 'DIGIEVER';
+  const truncated = Buffer.from([0xff, 0xd8, 0x01, 0x02]);
+  const valid = Buffer.from([0xff, 0xd8, 0x03, 0x04, 0xff, 0xd9]);
+  const wire = Buffer.concat([
+    Buffer.from(
+      '--' + boundary + '\r\nContent-Type: image/jpeg\r\n\r\n',
+    ),
+    truncated,
+    Buffer.from(
+      '\r\n--' +
+        boundary +
+        '\r\nContent-Type: image/jpeg\r\nContent-Length: ' +
+        valid.length +
+        '\r\n\r\n',
+    ),
+    valid,
+    Buffer.from('\r\n--' + boundary + '--\r\n'),
+  ]);
+  let cancelled = false;
+
+  const result = await fetchCctvImageFromUpstream(
+    'https://cctv-ss02.thb.gov.tw/T62-9K+020',
+    {
+      maxBytes: 1024,
+      fetchImpl: async () =>
+        multipartResponse(
+          'multipart/x-mixed-replace; boundary=' + boundary,
+          [wire],
+          { onCancel: () => { cancelled = true; } },
+        ),
+    },
+  );
+
+  assert.equal(result, null);
+  assert.equal(cancelled, true);
+});

src/data/cctvTaiwan.test.mjs

@@ -182,6 +182,86 @@ test('loader deduplicates cameras that share a camera number', async (t) => {
   ]);
 });
 
+test('falls back to Highway Bureau MJPEG cameras when the Freeway catalog fails', async (t) => {
+  const highwayUrl = 'https://cctv-maintain.thb.gov.tw/opendataCCTVs.xml';
+  const requests = [];
+  t.mock.method(console, 'log', () => {});
+  t.mock.method(console, 'warn', () => {});
+  t.mock.method(globalThis, 'fetch', async (url, options) => {
+    const href = String(url);
+    requests.push(href);
+    assert.equal(options.redirect, 'manual');
+    if (href === TAIWAN_FREEWAY_CCTV_URL)
+      return new Response('', { status: 503 });
+    if (href === highwayUrl) {
+      return new Response(
+        cctvXml(
+          block({
+            id: 'CCTV-14-0620-009-002',
+            stream: 'https://cctv-ss02.thb.gov.tw:443/T62-9K+020',
+            lat: '24.9967',
+            lon: '121.4521',
+          }),
+        ),
+        { headers: { 'content-type': 'application/xml' } },
+      );
+    }
+    throw new Error('Unexpected Taiwan feed URL: ' + href);
+  });
+
+  const sources = await loadTaiwanSources();
+
+  assert.deepEqual(requests, [TAIWAN_FREEWAY_CCTV_URL, highwayUrl]);
+  assert.equal(sources.length, 1);
+  assert.equal(sources[0].id, 'tw-thb-cctv-14-0620-009-002');
+  assert.equal(sources[0].cityId, 'taiwan');
+  assert.equal(sources[0].provider, 'Highway Bureau, MOTC');
+  assert.equal(sources[0].feedType, 'mjpeg');
+  assert.equal(sources[0].sourceKind, 'taiwan-highway-motc');
+  assert.equal(new URL(sources[0].url).hostname, 'cctv-ss02.thb.gov.tw');
+  assert.equal(new URL(sources[0].url).pathname, '/T62-9K+020');
+});
+
+test('the Highway Bureau fallback registers only approved HTTPS camera servers', async (t) => {
+  const highwayUrl = 'https://cctv-maintain.thb.gov.tw/opendataCCTVs.xml';
+  t.mock.method(console, 'log', () => {});
+  t.mock.method(console, 'warn', () => {});
+  t.mock.method(globalThis, 'fetch', async (url) => {
+    if (String(url) === TAIWAN_FREEWAY_CCTV_URL)
+      return new Response('', { status: 503 });
+    if (String(url) === highwayUrl) {
+      return new Response(
+        cctvXml(
+          block({
+            id: 'CCTV-14-0620-009-001',
+            stream: 'https://cctv-ss09.thb.gov.tw/T62-9K+019',
+          }),
+          block({
+            id: 'CCTV-14-0620-009-003',
+            stream: 'http://cctv-ss02.thb.gov.tw/T62-9K+021',
+          }),
+          block({
+            id: 'CCTV-14-0620-009-004',
+            stream: 'https://cctv-ss02.thb.gov.tw:8443/T62-9K+022',
+          }),
+          block({
+            id: 'CCTV-14-0620-009-002',
+            stream: 'https://cctv-ss02.thb.gov.tw:443/T62-9K+020',
+          }),
+        ),
+        { headers: { 'content-type': 'application/xml' } },
+      );
+    }
+    throw new Error('Unexpected Taiwan feed URL: ' + String(url));
+  });
+
+  const sources = await loadTaiwanSources();
+
+  assert.deepEqual(
+    sources.map((source) => source.id),
+    ['tw-thb-cctv-14-0620-009-002'],
+  );
+});
 test('a redirected or failed catalog contributes an empty pack', async (t) => {
   t.mock.method(console, 'warn', () => {});
   for (const status of [302, 503]) {
@@ -214,13 +294,17 @@ test('the Taiwan pack is in the catalog by default', async (t) => {
   );
 });
 
-test('CCTV_TAIWAN_ENABLED=0 makes no Freeway Bureau request', async (t) => {
+test('CCTV_TAIWAN_ENABLED=0 makes no Taiwan catalog request', async (t) => {
   const { requested, sources } = await runCatalogWithTaiwanFlag(t, '0');
   assert.ok(requested.length > 0, 'the other packs still refreshed');
   assert.equal(
     requested.some((href) => href.includes('freeway.gov.tw')),
     false,
   );
+  assert.equal(
+    requested.some((href) => href.includes('cctv-maintain.thb.gov.tw')),
+    false,
+  );
   assert.ok(!sources.some((c) => c.cityId === 'taiwan'));
 });
 
@@ -250,12 +334,12 @@ test('a failed download is not retried until the backoff ends', async (t) => {
   t.mock.method(Date, 'now', () => 1_000_000);
   assert.deepEqual(await loadTaiwanSources(), []);
   assert.deepEqual(await loadTaiwanSources(), []);
-  assert.equal(calls, 1, 'the second refresh made no request');
+  assert.equal(calls, 2, 'the second refresh made no request');
   Date.now.mock.mockImplementation(
     () => 1_000_000 + TAIWAN_RETRY_AFTER_FAILURE_MS + 1,
   );
   await loadTaiwanSources();
-  assert.equal(calls, 2, 'the backoff ends after an hour');
+  assert.equal(calls, 4, 'the backoff ends after an hour');
 });
 
 test('a failed download serves the last good table', async (t) => {