feat: optional authentication

README.md

@@ -88,4 +88,18 @@ from fastapi import Depends
 @app.get("/")
 def hello_world(auth: CognitoToken = Depends(cognito_eu.auth_required)):
     return {"message": "Hello world"}
+```
+
+### Optional authentication
+
+If authentication should be optional, we can use ```cognito_eu.auth_optional```
+
+Example:
+```python
+from fastapi_cognito import CognitoToken
+from fastapi import Depends
+
+@app.get("/")
+def hello_world(auth: CognitoToken = Depends(cognito_eu.auth_optional)):
+    return {"message": "Hello world"}
 ```

requirements.txt

@@ -24,7 +24,7 @@ pycparser==2.20
 pydantic==1.8.1
 Pygments==2.8.1
 pyparsing==2.4.7
-python-jose==3.2.0
+python-jose==3.3.0
 pywin32-ctypes==0.2.0
 PyYAML==5.4.1
 readme-renderer==29.0

src/fastapi_cognito/fastapi_cognito.py

@@ -1,4 +1,4 @@
-from typing import Dict
+from typing import Dict, Optional
 
 from cognitojwt import CognitoJWTException, decode as cognito_jwt_decode
 from fastapi.exceptions import HTTPException
@@ -173,6 +173,28 @@ def _decode_token(self, token) -> Dict:
                        "your userpool region config might be incorrect."
             )
 
+    def auth_optional(self, request: Request) -> Optional[CognitoToken]:
+        """
+        Optional authentication, method will try to parse `Authorization` header
+        if present, else it will return None
+        :param request: Incoming request
+        :return: CognitoToken or None
+        """
+        authorization_header = request.headers.get(
+            self._jwt_header_name.lower()
+        )
+
+        if not authorization_header:
+            return None
+
+        token = self._verify_header(auth_header_value=authorization_header)
+
+        try:
+            payload = self._decode_token(token=token)
+        except CognitoJWTException as error:
+            raise HTTPException(status_code=401, detail=str(error))
+        return CognitoToken(**payload)
+
     def auth_required(self, request: Request) -> CognitoToken:
         """
         Get token from request `Authorization` header use `_verify_header` to

src/fastapi_cognito/models.py

@@ -1,4 +1,4 @@
-from typing import Union, Dict, List, Set, Any
+from typing import Union, Dict, List, Set, Any, Optional
 
 from pydantic import BaseModel, HttpUrl, Field
 
@@ -12,7 +12,7 @@ class UserpoolModel(BaseModel):
 class CognitoToken(BaseModel):
     origin_jti: str
     cognito_id: str = Field(alias="sub")
-    event_id: str
+    event_id: Optional[str]
     token_use: str
     scope: str
     auth_time: int