Repository structure for pairing & authentication

[Flix6x]

Goal

We wish to include working examples of the pairing and authentication process between client and server, while acknowledging that production implementations will likely want to integrate this process in their own application, using their own dependencies.

Approach

• Create abstract classes for client and server.
• Create subclasses for client and server using specific dependencies (e.g. FastAPI) that are not part of the default s2-python installation.

Related work

• Added S2Pairing implementation #85 (first implementation of S2 pairing)
• Dependency on websockets #72 (optional WS dependencies)

Proposed structure

Usable with pip install s2-python:

• src/s2python/specification/s2-pairing/yml with the OpenAPI specification for the pairing & authentication process
• src/s2python/generated/gen_s2_pairing.py with PairingRequest, etc.
• src/s2python/authorization/
  • client.py with AbstractAuthClient
  • server.py with AbstractAuthServer
  • service.py with HTTPAuthServer(AbstractAuthServer)
  • tbd: AsyncAuthClient(AbstractAuthClient)?

Usable with pip install s2-python[ws]:

• src/s2python/s2_connection.py (currently actually a RM in WS server mode?)

Usable with pip install s2-python[fastapi]:

• src/s2python/authorization/fastapi_service.py with FastAPIAuthServer(AbstractAuthServer)

Usable with pip install s2-python[flask]:

• src/s2python/authorization/flask_service.py with FlaskAuthServer(AbstractAuthServer)

In flexmeasures-s2 (installed with pip install flexmeasures-s2):

• FlexMeasuresAuthServer(FlaskAuthServer)

Relevant code snippets

try:
    import fastapi
except ImportError:
    raise ImportError("You need to run 'pip install s2-python[fastapi]' to use this feature.")

In pyproject.toml setup.cfg:

[project.optional-dependencies]
fastapi =
    fastapi
flask =
    Flask

[VladIftime]

The two PRs dealing with this are #102 and #103