feat: add CORS middleware for fastapi to make it easier to use

encord_agents/fastapi/cors.py

@@ -0,0 +1,60 @@
+"""
+Convenience method to easily extend FastAPI servers
+with the appropriate CORS Middleware to allow
+interactions from the Encord platform.
+"""
+
+import typing
+
+try:
+    from fastapi.middleware.cors import CORSMiddleware
+    from starlette.types import ASGIApp
+except ModuleNotFoundError:
+    print(
+        'To use the `fastapi` dependencies, you must also install fastapi. `python -m pip install "fastapi[standard]"'
+    )
+    exit()
+
+ENCORD_DOMAIN_REGEX = (
+    r"^https:\/\/(?:(?:cord-ai-development--[\w\d]+-[\w\d]+\.web.app)|(?:(?:dev|staging|app)\.encord\.com))$"
+)
+
+
+class EncordCORSMiddleware(CORSMiddleware):
+    """
+    Like a regular `fastapi.midleware.cors.CORSMiddleware` but matches against
+    the encord origin by default.
+
+    **Example:**
+    ```python
+    from fastapi import FastAPI
+    from encord_agents.fastapi.cors import EncordCORSMiddleware
+
+    app = FastAPI()
+    app.add_middleware(EncordCORSMiddleware)
+    ```
+
+    The CORS middleware will allow POST requests from the Encord domain.
+    """
+
+    def __init__(
+        self,
+        app: ASGIApp,
+        allow_origins: typing.Sequence[str] = (),
+        allow_methods: typing.Sequence[str] = ("POST",),
+        allow_headers: typing.Sequence[str] = (),
+        allow_credentials: bool = False,
+        allow_origin_regex: str = ENCORD_DOMAIN_REGEX,
+        expose_headers: typing.Sequence[str] = (),
+        max_age: int = 3600,
+    ) -> None:
+        super().__init__(
+            app,
+            allow_origins,
+            allow_methods,
+            allow_headers,
+            allow_credentials,
+            allow_origin_regex,
+            expose_headers,
+            max_age,
+        )