CADbuildr Broker

WebRTC broker for CADbuildr that mediates communication between Foundation and a viewer page.

Status

green

Runtime contract

The broker is local-first. Keep heavy CAD data local.

• Data path (heavy): Foundation -> local broker /send -> WebRTC DataChannel -> viewer.
• Signaling path (lightweight): viewer/broker offer-answer exchange via signaling API.
• Signaling can be local or remote/authenticated.
• The broker does not need to relay CAD DAG payloads through cloud endpoints.

Installation

From PyPI

pip install cadbuildr-broker

From monorepo (development)

cd py/packages/broker
poetry install

Usage

Start with hosted Hub signaling (default):

cadbuildr-broker

Equivalent monorepo command:

cd py/packages/broker
poetry run cadbuildr-broker

Use local signaling (Hub on localhost) by overriding defaults:

cadbuildr-broker \
  --host localhost \
  --port 3000 \
  --signaling-scheme http

Or set an explicit signaling API base URL:

cadbuildr-broker \
  --signaling-base-url https://hub.cadbuildr.com/api/webrtc

Use remote signaling with auth:

CADBUILDR_SIGNALING_BEARER_TOKEN="<token>" \
cadbuildr-broker \
  --signaling-base-url https://hub.cadbuildr.com/api/webrtc

CLI options

• --host: signaling host (default: hub.cadbuildr.com)
• --port: signaling port (default: 443)
• --signaling-scheme: http or https (default: https)
• --signaling-base-url: full signaling API base URL, for example https://hub.cadbuildr.com/api/webrtc
• --auth-bearer-token: optional bearer token for signaling requests (or use env CADBUILDR_SIGNALING_BEARER_TOKEN)
• --broker-port: local HTTP port used by Foundation and screenshot upload (default: 5050)

What runs where

1. Broker polls signaling API for offers.
2. Viewer creates WebRTC offer and receives answer.
3. Foundation posts DAG to broker /send on localhost.
4. Broker forwards DAG to viewer via DataChannel.
5. Viewer posts screenshots/log payloads back to broker.

Publishing

Recommended release flow:

cd py/packages/broker
poetry build
poetry config repositories.testpypi https://test.pypi.org/legacy/
poetry publish --repository testpypi
pip install -i https://test.pypi.org/simple cadbuildr-broker
poetry publish

If your environment uses token-based publishing, configure Poetry credentials before publishing.