Dependency Injection¶
The markers that declare what a handler needs and how it is authorised.
Dependency marker — use in function signature defaults.
dependency may be omitted (Depends()); the resolver then infers
it from the parameter's type annotation — the shorthand for
x: SomeClass = Depends().
Usage::
def get_db() -> Database:
return Database()
@app.get("/users")
async def list_users(db: Database = Depends(get_db)) -> list[str]:
return db.all_usernames()
Aggregated OAuth 2.0 scopes for the current Security() chain.
A handler / sub-dependency that declares a parameter of this type
receives the union of all Security(..., scopes=[...]) calls between
the route entry and this point in the dependency graph. Typical use:
an authorising dependency checks security_scopes.scopes against
the scopes the bearer token actually carries and builds a
WWW-Authenticate: Bearer scope="<...>" header when denying.
Per RFC 6749 Sec. 3.3 the scope-string serialisation is space-separated.