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Camera Control Node.js Client

An ES module library and the camera-control command-line client for Camera Control protocol version 4. It supports status, idempotent single capture, and cancellable time-lapse operation over verified TLS. Status polling reconnects with bounded exponential backoff when Wi-Fi or the server connection is interrupted.

Requirements and installation

  • Node.js 18.17 or newer
  • Camera Control's TLS-only WebSocket API enabled and running
  • The verified local CA certificate shown by the phone app
cd node
npm install
npm link      # optional: puts `camera-control` on PATH

Set the password without exposing it in process arguments:

export CAMERA_CONTROL_PASSWORD='your password'

If this variable isn't present, the CLI prompts without echoing the password.

Commands

Read camera, device, capture-session, and reliability status:

node bin/camera-control.js status wss://192.168.1.50:8080/ws \
  --ca camera-control-local-ca.crt

Capture and save one JPEG through the idempotent job API:

node bin/camera-control.js capture wss://192.168.1.50:8080/ws \
  --ca camera-control-local-ca.crt \
  --camera 1 --resolution high --flash off \
  --jpeg-quality 90 --rotation 90 --output photo.jpg

Rotation accepts 0, 90, 180, or 270 clockwise degrees. Omit the flag to keep the current app setting; use --rotation 0 to reset it. The app starts at 0°. Rotation applies to new photos and live previews; existing gallery photos keep their orientation. Library callers pass "rotation": 90 in the existing controls map. Check status.capabilities.rotation for support.

Start a 5-second time lapse, stopping after 20 photos:

node bin/camera-control.js time-lapse wss://192.168.1.50:8080/ws \
  --ca camera-control-local-ca.crt \
  --interval 5 --count 20

Omit --count to run until Ctrl+C, or use --duration SECONDS. The client polls session status, reconnects between polls, and requests server-side cancellation when stopped.

Library usage

import { writeFile } from 'node:fs/promises';
import { CameraControlClient, decodePhoto } from 'camera-control-client';

const camera = new CameraControlClient(
  'wss://192.168.1.50:8080/ws',
  process.env.CAMERA_CONTROL_PASSWORD,
  'camera-control-local-ca.crt',
);

await camera.connect();
try {
  console.log(await camera.status());
  const job = await camera.captureJob({ requestId: 'document-page-42' });
  await writeFile('photo.jpg', decodePhoto(job.result.photo));
} finally {
  camera.close();
}

captureJob retries reuse the same semantic requestId, allowing the running app process to deduplicate an ambiguous reconnect. Do not deliberately reuse a request ID with different capture settings. If the phone app itself restarts, its in-memory idempotency history is lost; verify status before replaying an ambiguous capture.

Certificate bootstrap

Download the CA from the URL shown by the app, then compare its SHA-256 fingerprint with the phone before trusting it:

curl --insecure --output camera-control-local-ca.crt \
  https://192.168.1.50:8080/ca.crt
openssl x509 -in camera-control-local-ca.crt -noout -fingerprint -sha256

--insecure is only for the initial CA download. The library passes the CA to ws as the only trusted root, so certificate verification stays on.

Run tests with:

npm test

See ../api.md for the command and event summary.