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fix(screenshot): resolve dev screenshot path instead of hardcoding .png #1

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fix(screenshot): resolve dev screenshot path instead of hardcoding .png #1

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71 changes: 71 additions & 0 deletions src/__tests__/client-unit.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -227,3 +227,74 @@ describe('app-level typed errors', () => {
expect(err.message).toBe('test');
});
});

describe('takeScreenshot', () => {
const bigImage = Buffer.alloc(2000, 7);

// Roku's dev-mode screenshot format is device-dependent: HD (720p) TVs write
// a JPEG at /pkgs/dev.jpg, newer/4K models write a PNG at /pkgs/dev.png.
// `reportedPath` is what the /plugin_inspect POST response advertises;
// `servedExt` is the extension the device actually serves a 200 for.
function mockScreenshotFetch(reportedPath: string, servedExt: 'jpg' | 'png') {
vi.stubGlobal(
'fetch',
vi.fn(async (url: string | URL) => {
const u = url.toString();
if (u.includes('/plugin_inspect')) {
const body = reportedPath
? `<html><img src="${reportedPath}?time=123" /></html>`
: '<html>Screenshot ok</html>';
return new Response(body, { status: 200 });
}
if (u.includes(`dev.${servedExt}`)) {
return new Response(bigImage, { status: 200 });
}
// Any other extension does not exist on this device model.
return new Response('not found', { status: 404 });
}),
);
}

it('fetches the JPEG path an HD TV reports, never requesting the missing .png', async () => {
mockScreenshotFetch('pkgs/dev.jpg', 'jpg');
const client = new EcpClient('192.168.0.1');
const img = await client.takeScreenshot();
expect(img.length).toBe(2000);

const urls = (fetch as unknown as ReturnType<typeof vi.fn>).mock.calls.map((c) =>
String(c[0]),
);
expect(urls.some((u) => u.includes('dev.jpg'))).toBe(true);
expect(urls.some((u) => u.includes('dev.png'))).toBe(false);
});

it('falls back to .jpg when the reported .png path 404s', async () => {
// Response advertises .png but the device only serves the .jpg.
mockScreenshotFetch('pkgs/dev.png', 'jpg');
const client = new EcpClient('192.168.0.1');
const img = await client.takeScreenshot();
expect(img.length).toBe(2000);
});

it('tries both extensions when the response advertises no path', async () => {
mockScreenshotFetch('', 'png');
const client = new EcpClient('192.168.0.1');
const img = await client.takeScreenshot();
expect(img.length).toBe(2000);
});

it('throws EcpScreenshotError when no candidate yields an image', async () => {
vi.stubGlobal(
'fetch',
vi.fn(async (url: string | URL) => {
const u = url.toString();
if (u.includes('/plugin_inspect')) {
return new Response('<html></html>', { status: 200 });
}
return new Response('not found', { status: 404 });
}),
);
const client = new EcpClient('192.168.0.1');
await expect(client.takeScreenshot()).rejects.toBeInstanceOf(EcpScreenshotError);
});
});
37 changes: 29 additions & 8 deletions src/client.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -544,25 +544,46 @@ export class EcpClient {
async takeScreenshot(): Promise<Buffer> {
const devUrl = `http://${this.deviceIp}`;

await digestUpload(
// The capture format is device-dependent: HD (720p) Roku TVs write the
// screenshot as a JPEG at /pkgs/dev.jpg, while newer/4K models write a PNG
// at /pkgs/dev.png. Fetching a hardcoded extension 404s on half of devices,
// so we read the actual path the device reports in the POST response HTML
// (e.g. src="pkgs/dev.jpg?time=..."), and fall back to trying both.
const html = await digestUpload(
`${devUrl}/plugin_inspect`,
'rokudev',
this.devPassword,
{ mysubmit: 'Screenshot' },
{},
);

const png = await digestGet(
`${devUrl}/pkgs/dev.png?time=${Date.now()}`,
'rokudev',
this.devPassword,
);
const reported = html.match(/pkgs\/dev\.(png|jpe?g)/i)?.[0];
const candidates = reported
? [reported, ...['pkgs/dev.jpg', 'pkgs/dev.png'].filter((p) => p !== reported)]
: ['pkgs/dev.jpg', 'pkgs/dev.png'];

let image: Buffer | undefined;
for (const path of candidates) {
try {
const data = await digestGet(
`${devUrl}/${path}?time=${Date.now()}`,
'rokudev',
this.devPassword,
);
if (data.length >= 1000) {
image = data;
break;
}
} catch {
// Wrong extension for this device model — try the next candidate.
}
}

if (png.length < 1000) {
if (!image) {
throw new EcpScreenshotError('Screenshot failed — is a dev channel sideloaded?');
}

return png;
return image;
}

/* ---- SSDP Discovery ---- */
Expand Down