| 13 | |
| 14 | |
| 15 | class CORSMiddleware: |
| 16 | def __init__( |
| 17 | self, |
| 18 | app: ASGIApp, |
| 19 | allow_origins: Collection[str] = (), |
| 20 | allow_methods: Collection[str] = ("GET",), |
| 21 | allow_headers: Collection[str] = (), |
| 22 | allow_credentials: bool = False, |
| 23 | allow_origin_regex: str | None = None, |
| 24 | allow_private_network: bool = False, |
| 25 | expose_headers: Collection[str] = (), |
| 26 | max_age: int = 600, |
| 27 | ) -> None: |
| 28 | if "*" in allow_methods: |
| 29 | allow_methods = ALL_METHODS |
| 30 | |
| 31 | compiled_allow_origin_regex = None |
| 32 | if allow_origin_regex is not None: |
| 33 | compiled_allow_origin_regex = re.compile(allow_origin_regex) |
| 34 | |
| 35 | allow_all_origins = "*" in allow_origins |
| 36 | allow_all_headers = "*" in allow_headers |
| 37 | preflight_explicit_allow_origin = not allow_all_origins or allow_credentials |
| 38 | |
| 39 | simple_headers: dict[str, str] = {} |
| 40 | if allow_all_origins: |
| 41 | simple_headers["Access-Control-Allow-Origin"] = "*" |
| 42 | if allow_credentials: |
| 43 | simple_headers["Access-Control-Allow-Credentials"] = "true" |
| 44 | if expose_headers: |
| 45 | simple_headers["Access-Control-Expose-Headers"] = ", ".join(expose_headers) |
| 46 | |
| 47 | preflight_headers: dict[str, str] = { |
| 48 | "Vary": "Origin, Access-Control-Request-Method, Access-Control-Request-Headers, Access-Control-Request-Private-Network" # noqa: E501 # fmt: skip |
| 49 | } |
| 50 | if not preflight_explicit_allow_origin: |
| 51 | preflight_headers["Access-Control-Allow-Origin"] = "*" |
| 52 | preflight_headers.update( |
| 53 | { |
| 54 | "Access-Control-Allow-Methods": ", ".join(allow_methods), |
| 55 | "Access-Control-Max-Age": str(max_age), |
| 56 | } |
| 57 | ) |
| 58 | allow_headers = sorted(SAFELISTED_HEADERS | set(allow_headers)) |
| 59 | if allow_headers and not allow_all_headers: |
| 60 | preflight_headers["Access-Control-Allow-Headers"] = ", ".join(allow_headers) |
| 61 | if allow_credentials: |
| 62 | preflight_headers["Access-Control-Allow-Credentials"] = "true" |
| 63 | |
| 64 | self.app = app |
| 65 | self.allow_origins = allow_origins |
| 66 | self.allow_methods = allow_methods |
| 67 | self.allow_headers = [h.lower() for h in allow_headers] |
| 68 | self.allow_all_origins = allow_all_origins |
| 69 | self.allow_all_headers = allow_all_headers |
| 70 | self.allow_credentials = allow_credentials |
| 71 | self.preflight_explicit_allow_origin = preflight_explicit_allow_origin |
| 72 | self.allow_origin_regex = compiled_allow_origin_regex |
no outgoing calls