opencad-backend 0.2.0

OpenCAD HTTP backend — FastAPI transport over the OpenCAD core and agent

opencad-backend

FastAPI transport over the OpenCAD core. This is the only distribution in the repository that depends on a web framework — opencad and opencad-agent carry no FastAPI, Starlette, httpx, or uvicorn.

Run

uv run --package opencad-backend --extra occt \
  python -m uvicorn opencad_server.app:app --reload --port 8000

opencad_server.app mounts every service router in one process:

Prefix	Router	Service
/kernel	opencad_server.kernel_router	Geometry operations, topology, mesh
/solver	opencad_server.solver_router	2-D constraint solving and diagnostics
/tree	opencad_server.tree_router	Feature DAG CRUD, rebuild, branching
/agent	opencad_server.agent_router	Natural-language modelling

Each router module also exposes create_app() and a module-level app, so any service can run standalone — for example opencad_server.kernel_router:app.

Modules

• app.py — aggregate app, mounts every router
• api_app.py — shared FastAPI factory with production CORS/docs defaults
• http_kernel_client.py — the only outbound HTTP client to the kernel; implements opencad.kernel.client.KernelClient
• *_router.py — one router per service

Kernel transport

Core packages depend on the KernelClient protocol, never on a transport. This app chooses the implementation at startup: HttpKernelClient when OPENCAD_TREE_LIVE_KERNEL / OPENCAD_AGENT_LIVE_KERNEL are true, otherwise the in-process default.

Tests

OPENCAD_KERNEL_BACKEND=analytic pytest

tests/test_core_boundary.py parses every core module and fails if any of them imports FastAPI, Starlette, httpx, uvicorn, python-dotenv, or opencad_server.