FastAPI Native Example

The FastAPI example uses the native binding and a real Cedar schema. It loads its own examples/fastapi_simple/policy.dw and examples/fastapi_simple/schema.cedarschema plus examples/fastapi_simple/event.dwschema, creates a persistent native.NativeAuthorizer, and exposes an authorization endpoint.

The policy enforces a $50 daily transfer limit per user. Three $20 transfers by the same user produce:

Allow, Allow, Deny

Run it:

make develop
make examples-deps
make fastapi-example

First transfer:

curl -s http://127.0.0.1:8000/authorize \
  -H 'content-type: application/json' \
  -d '{"user":"alice","amount":20}'

Expected response:

{"decision":"Allow","allowed":true,"daily_limit":50}

Second transfer:

curl -s http://127.0.0.1:8000/authorize \
  -H 'content-type: application/json' \
  -d '{"user":"alice","amount":20}'

Expected response:

{"decision":"Allow","allowed":true,"daily_limit":50}

Third transfer:

curl -s http://127.0.0.1:8000/authorize \
  -H 'content-type: application/json' \
  -d '{"user":"alice","amount":20}'

Expected response:

{"decision":"Deny","allowed":false,"daily_limit":50}

Dogwood authorizers are stateful. The example keeps one shared native authorizer and protects it with a lock. For high-throughput services, use a pool or request-partitioned authorizers based on your temporal semantics.

The same FastAPI app also includes a quota-based rate limit endpoint:

curl -s http://127.0.0.1:8000/authorize/quota \
  -H 'content-type: application/json' \
  -d '{"user":"carol","amount":1}'

That endpoint uses examples/fastapi_simple/quota_policy.dw, which permits fewer than three transfers by the same user within one hour. For one user, the first two requests are allowed and the third is denied.