Validate provider response formats

CCTV frames and the Street View fallback accept only JPEG, PNG, GIF, WebP and
AVIF, parsed from the media type essence and sent under the canonical type;
any other type is cancelled and falls through to the next fallback as a
failed upstream does. Live media must match its feed kind (video/mp4,
video/webm, or multipart/x-mixed-replace with a boundary) before the camera
is reported healthy or any byte is relayed, and its redirects now stay on the
registered origin like frames. Every /api/cctv route uses the same-site gate.

The GBFS proxy relays only bodies that parse as JSON, re-serialized under a
fixed application/json type.

src/data/cctvMediaFeedType.test.mjs

@@ -33,6 +33,14 @@ const VIDEO = {
   feedType: 'video',
   url: 'https://cams.upstream.invalid/live.mp4',
 };
+const WEBM = {
+  id: 'webm-fixture',
+  name: 'WebM fixture',
+  lat: 30.27,
+  lon: -97.74,
+  feedType: 'webm',
+  url: 'https://cams.upstream.invalid/live.webm',
+};
 const MJPEG = {
   id: 'mjpeg-fixture',
   name: 'MJPEG fixture',
@@ -69,7 +77,10 @@ function recordingResponse() {
     body: '',
     writeHead(status, headers) {
       res.statusCode = status;
-      res.headers = headers || {};
+      res.headers = { ...res.headers, ...headers };
+    },
+    setHeader(name, value) {
+      res.headers[name] = value;
     },
     write(chunk) {
       chunks.push(Buffer.from(chunk));
@@ -105,6 +116,7 @@ function mount(t, respond) {
     STILL,
     STILL_ALIAS,
     VIDEO,
+    WEBM,
     MJPEG,
   ]);
   process.env.CCTV_SOURCES_FILE = 'absent-source-file.json';
@@ -143,9 +155,9 @@ function mount(t, respond) {
   });
   assert.ok(handler, 'the CCTV provider must mount a middleware');
 
-  const call = async (path) => {
+  const call = async (path, headers = {}) => {
     const { res, done } = recordingResponse();
-    await handler({ url: path, headers: {}, method: 'GET', on() {} }, res);
+    await handler({ url: path, headers, method: 'GET', on() {} }, res);
     await done;
     return res;
   };
@@ -268,3 +280,195 @@ test('/frame does not follow a still camera off its origin', async (t) => {
     [STILL.url],
   );
 });
+
+/** An upstream Response whose body records whether it was cancelled. */
+function trackedUpstream({ status = 200, headers = {}, body = 'payload' }) {
+  const state = { cancelled: false };
+  const response = new Response(
+    new ReadableStream(
+      {
+        pull(controller) {
+          controller.enqueue(new TextEncoder().encode(body));
+          controller.close();
+        },
+        cancel() {
+          state.cancelled = true;
+        },
+      },
+      { highWaterMark: 0 },
+    ),
+    { status, headers },
+  );
+  return { response, state };
+}
+
+test('/media refuses an upstream type that does not match the feed kind', async (t) => {
+  let current;
+  const app = mount(t, () => current.response);
+  for (const [camera, contentType, body] of [
+    [VIDEO, 'text/html', '<!doctype html><p>x</p>'],
+    [VIDEO, 'image/svg+xml', '<svg xmlns="http://www.w3.org/2000/svg"/>'],
+    [VIDEO, 'application/vnd.apple.mpegurl', '#EXTM3U'],
+    [VIDEO, 'video/webm', 'video'],
+    [VIDEO, undefined, 'video'],
+    [WEBM, 'video/mp4', 'video'],
+    [MJPEG, 'multipart/x-mixed-replace', '--frame'],
+    [MJPEG, 'multipart/x-mixed-replace; boundary=', '--frame'],
+    [MJPEG, 'image/jpeg', 'jpeg'],
+    [MJPEG, 'text/html; boundary=frame', '<!doctype html><p>x</p>'],
+  ]) {
+    current = trackedUpstream({
+      headers: contentType === undefined ? {} : { 'content-type': contentType },
+      body,
+    });
+    const label = `${camera.id}: ${contentType}`;
+    const res = await app.call(`/media/${camera.id}`);
+    assert.equal(res.statusCode, 502, label);
+    assert.equal(res.headers['Content-Type'], 'application/json', label);
+    assert.deepEqual(JSON.parse(res.body), { error: 'Media proxy failed' });
+    assert.equal(current.state.cancelled, true, `${label}: upstream cancelled`);
+    const health = await app.health(camera.id);
+    assert.equal(health.status, 'degraded', label);
+    assert.equal(health.message, 'Unexpected media type', label);
+  }
+});
+
+test('/media relays each feed kind under its canonical type, including a partial response', async (t) => {
+  let current;
+  const app = mount(t, () => current);
+  for (const [camera, upstream, expected] of [
+    [
+      VIDEO,
+      { 'content-type': 'Video/MP4; codecs="avc1.42E01E"' },
+      'video/mp4',
+    ],
+    [
+      VIDEO,
+      {
+        'content-type': 'video/mp4',
+        'content-range': 'bytes 0-4/100',
+        'content-length': '5',
+        'accept-ranges': 'bytes',
+      },
+      'video/mp4',
+    ],
+    [WEBM, { 'content-type': 'video/webm' }, 'video/webm'],
+    [
+      MJPEG,
+      { 'content-type': 'multipart/x-mixed-replace;boundary="frame"' },
+      'multipart/x-mixed-replace; boundary=frame',
+    ],
+    [
+      MJPEG,
+      { 'content-type': 'multipart/x-mixed-replace; boundary="a b"' },
+      'multipart/x-mixed-replace; boundary="a b"',
+    ],
+  ]) {
+    const status = upstream['content-range'] ? 206 : 200;
+    current = upstreamResponse({ status, headers: upstream, body: 'bytes' });
+    const res = await app.call(`/media/${camera.id}`);
+    assert.equal(res.statusCode, status, camera.id);
+    assert.equal(res.headers['Content-Type'], expected);
+    assert.equal(res.body, 'bytes');
+    if (status === 206)
+      assert.equal(res.headers['Content-Range'], 'bytes 0-4/100');
+    assert.equal((await app.health(camera.id)).status, 'ok');
+  }
+});
+
+test('/media does not follow a live camera off its origin', async (t) => {
+  const app = mount(t, ({ url }) =>
+    url === VIDEO.url
+      ? upstreamResponse({
+          status: 302,
+          headers: { location: 'https://elsewhere.invalid/live.mp4' },
+          body: '',
+        })
+      : upstreamResponse({
+          headers: { 'content-type': 'video/mp4' },
+          body: 'elsewhere',
+        }),
+  );
+  const res = await app.call(`/media/${VIDEO.id}`);
+  assert.equal(res.statusCode, 502);
+  assert.doesNotMatch(res.body, /elsewhere/);
+  assert.deepEqual(app.requests, [{ url: VIDEO.url, redirect: 'manual' }]);
+});
+
+test('every CCTV route refuses cross-site requests and admits the app itself', async (t) => {
+  const app = mount(t, ({ url }) =>
+    upstreamResponse({
+      headers: {
+        'content-type': url === VIDEO.url ? 'video/mp4' : 'image/jpeg',
+      },
+      body: 'bytes',
+    }),
+  );
+  const host = 'localhost:5173';
+  const paths = [
+    '/sources',
+    '/health',
+    `/stream/${STILL.id}`,
+    `/frame/${STILL.id}`,
+    `/media/${VIDEO.id}`,
+  ];
+  for (const headers of [
+    { host, 'sec-fetch-site': 'cross-site' },
+    { host, 'sec-fetch-site': 'same-site' },
+    { host, origin: 'https://elsewhere.example' },
+    { host, origin: 'null' },
+  ])
+    for (const path of paths) {
+      const res = await app.call(path, headers);
+      assert.equal(res.statusCode, 403, `${path} ${JSON.stringify(headers)}`);
+    }
+  assert.deepEqual(app.requests, [], 'a refused request reached an upstream');
+  for (const headers of [
+    { host, 'sec-fetch-site': 'same-origin' },
+    { host, origin: `http://${host}` },
+    {},
+  ]) {
+    const frame = await app.call(`/frame/${STILL.id}`, headers);
+    assert.equal(frame.statusCode, 200);
+    assert.equal(frame.headers['X-CCTV-Source'], 'upstream-image');
+    const media = await app.call(`/media/${VIDEO.id}`, headers);
+    assert.equal(media.statusCode, 200);
+    assert.equal(media.headers['Content-Type'], 'video/mp4');
+  }
+});
+
+test('/frame falls back past a non-raster upstream and Street View frame', async (t) => {
+  let streetViewType;
+  const app = mount(t, ({ url }) =>
+    url.startsWith('https://maps.googleapis.com/')
+      ? trackedUpstream({
+          headers:
+            streetViewType === undefined
+              ? {}
+              : { 'content-type': streetViewType },
+          body: 'street-view',
+        }).response
+      : upstreamResponse({
+          headers: { 'content-type': 'image/svg+xml' },
+          body: '<svg xmlns="http://www.w3.org/2000/svg"/>',
+        }),
+  );
+  process.env.GOOGLE_MAPS_SERVER_API_KEY = 'fixture-key';
+  for (const type of [
+    'image/svg+xml',
+    'text/html',
+    'application/xml',
+    undefined,
+  ]) {
+    streetViewType = type;
+    const res = await app.call(`/frame/${STILL.id}`);
+    assert.equal(res.statusCode, 200);
+    assert.equal(res.headers['X-CCTV-Source'], 'synthetic', String(type));
+    assert.doesNotMatch(res.body, /street-view/);
+  }
+  streetViewType = 'image/JPEG; charset=x';
+  const res = await app.call(`/frame/${STILL.id}`);
+  assert.equal(res.headers['X-CCTV-Source'], 'streetview');
+  assert.equal(res.headers['Content-Type'], 'image/jpeg');
+  assert.equal(res.body, 'street-view');
+});

src/data/cctvProxy.test.mjs

@@ -259,3 +259,57 @@ test('rejected snapshot responses abort the upstream download', async () => {
     assert.equal(signal.aborted, true);
   }
 });
+
+test('CCTV upstream frame fetch accepts only raster image types and sends their canonical type', async () => {
+  const frame = (contentType, body = 'frame') => {
+    const state = { cancelled: false };
+    const headers = contentType === null ? {} : { 'Content-Type': contentType };
+    const response = new Response(new ReadableStream({
+      pull(controller) {
+        controller.enqueue(new TextEncoder().encode(body));
+        controller.close();
+      },
+      cancel() {
+        state.cancelled = true;
+      },
+    }, { highWaterMark: 0 }), { status: 200, headers });
+    return { response, state };
+  };
+  for (const [contentType, canonical] of [
+    ['image/jpeg', 'image/jpeg'],
+    ['image/JPEG; charset=x', 'image/jpeg'],
+    [' Image/PNG ', 'image/png'],
+    ['image/gif', 'image/gif'],
+    ['image/webp;q=1', 'image/webp'],
+    ['image/avif', 'image/avif'],
+  ]) {
+    const { response } = frame(contentType);
+    const result = await fetchCctvImageFromUpstream('https://example.com/frame.jpg', {
+      fetchImpl: async () => response,
+    });
+    assert.equal(result?.contentType, canonical, contentType);
+    assert.equal(result.body.toString(), 'frame');
+  }
+  for (const [contentType, body] of [
+    ['image/svg+xml', '<svg xmlns="http://www.w3.org/2000/svg"/>'],
+    ['Image/SVG+XML; charset=utf-8', '<svg xmlns="http://www.w3.org/2000/svg"/>'],
+    ['text/html', '<!doctype html><p>x</p>'],
+    ['text/html; charset=utf-8', '<!doctype html><p>x</p>'],
+    ['application/xml', '<x/>'],
+    ['text/xml', '<x/>'],
+    [null, 'frame'],
+    ['', 'frame'],
+    ['image', 'frame'],
+    ['image/', 'frame'],
+    ['image/jpeg/x', 'frame'],
+    ['image/jpeg, text/html', 'frame'],
+    ['application/octet-stream', 'frame'],
+  ]) {
+    const { response, state } = frame(contentType, body);
+    const result = await fetchCctvImageFromUpstream('https://example.com/frame.jpg', {
+      fetchImpl: async () => response,
+    });
+    assert.equal(result, null, String(contentType));
+    assert.equal(state.cancelled, true, `${contentType}: body cancelled`);
+  }
+});

src/data/gbfsProxy.test.mjs

@@ -304,3 +304,61 @@ test('GBFS rejects redirects and caps bodies through both server hooks', async (
     globalThis.fetch = originalFetch;
   }
 });
+
+test('GBFS relays only JSON, re-serialized under a fixed type, through both server hooks', async () => {
+  const { gbfsProxy } = await import('../../server/providers/gbfs.js');
+  const originalFetch = globalThis.fetch;
+  try {
+    for (const hook of ['configureServer', 'configurePreviewServer']) {
+      let handler;
+      gbfsProxy()[hook]({
+        middlewares: {
+          use(_path, callback) {
+            handler = callback;
+          },
+        },
+      });
+      const request = async (response) => {
+        globalThis.fetch = async () => response;
+        const res = {};
+        await handler(
+          { method: 'GET', url: '/' + encodeURIComponent(STATION_URL) },
+          {
+            writeHead(code, headers) {
+              Object.assign(res, { status: code, headers });
+            },
+            end(value) {
+              res.body = value;
+            },
+          },
+        );
+        return res;
+      };
+      for (const [contentType, body] of [
+        ['text/html', '<!doctype html><p>x</p>'],
+        ['application/json', '<!doctype html><p>x</p>'],
+        ['image/svg+xml', '<svg xmlns="http://www.w3.org/2000/svg"/>'],
+        ['application/json', ''],
+      ]) {
+        const res = await request(
+          new Response(body, { headers: { 'Content-Type': contentType } }),
+        );
+        assert.equal(res.status, 502, `${hook}: ${contentType} ${body}`);
+        assert.equal(res.headers['Content-Type'], 'application/json');
+        assert.equal(typeof JSON.parse(res.body).error, 'string');
+        assert.doesNotMatch(res.body, /doctype|svg/);
+      }
+      const res = await request(
+        new Response(' { "data" : { "stations" : [] } } ', {
+          headers: { 'Content-Type': 'text/html; charset=iso-8859-1' },
+        }),
+      );
+      assert.equal(res.status, 200);
+      assert.equal(res.headers['Content-Type'], 'application/json; charset=utf-8');
+      assert.equal(res.headers['Cache-Control'], 'no-store');
+      assert.equal(res.body, STATION_BODY);
+    }
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});