Safir

Bug fixes

- Restore previous `http_client_dependency` behavior by enabling following redirects by default. This adjusts for the change of defaults in HTTPX 0.20.0.

Other changes

- Require structlog 21.2.0 and adjust logger configuration of exception handling for the expectations of that version.

New features

- Add `safir.models.ErrorModel`, which is a model of the error message format preferred by FastAPI. Using the model is not necessary but it's helpful to reference it in API documentation to generate more complete information about the error messages.

Bug fixes

- Mark all FastAPI dependencies as async so that FastAPI doesn't run them in an external thread pool.

New features

- Defer creation of `httpx.AsyncClient` until the first time it is requested. Allow re-creation after `aclose()`, which makes it easier to write test suites.

Backward-incompatible changes

As of this release, Safir is a helper library for FastAPI applications instead of aiohttp applications. Much of the library has changed. Authors of software that uses Safir should read the documentation again as part of the upgrade to FastAPI.

Included in this release is:

- A FastAPI dependency to provide a structlog logger as configured by the `safir.logging` package, replacing the aiohttp middleware.
- A FastAPI dependency to provide a global `httpx.AsyncClient`, replacing the middleware that provided an aiohttp client.
- Starlette (FastAPI) middleware to parse `X-Forwarded-*` headers and update request information accordingly.
- `safir.metadata.get_metadata` now returns a [Pydantic](https://docs.pydantic.dev/latest/) model.

As of this release, Safir only supports Python 3.8 or later.

Safir v1 will be the major release supporting aiohttp. Starting with Safir v2, Safir will become a support library for [FastAPI](https://fastapi.tiangolo.com/) applications.

This release has no significant difference from 0.2.0. The version bump is to indicate that the aiohttp support is stable.