refactor: Introduce utility functions for exception handling and database operations; update auth and playlist services to use new exception methods

app/utils/exceptions.py

@@ -0,0 +1,121 @@
+"""Utility functions for common HTTP exception patterns."""
+
+from fastapi import HTTPException, status
+
+
+def raise_not_found(resource: str, identifier: str = None) -> None:
+    """Raise a standardized 404 Not Found exception.
+    
+    Args:
+        resource: Name of the resource that wasn't found
+        identifier: Optional identifier for the specific resource
+        
+    Raises:
+        HTTPException with 404 status code
+    """
+    if identifier:
+        detail = f"{resource} with ID {identifier} not found"
+    else:
+        detail = f"{resource} not found"
+    
+    raise HTTPException(
+        status_code=status.HTTP_404_NOT_FOUND,
+        detail=detail,
+    )
+
+
+def raise_unauthorized(detail: str = "Could not validate credentials") -> None:
+    """Raise a standardized 401 Unauthorized exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 401 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail=detail,
+    )
+
+
+def raise_bad_request(detail: str) -> None:
+    """Raise a standardized 400 Bad Request exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 400 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_400_BAD_REQUEST,
+        detail=detail,
+    )
+
+
+def raise_internal_server_error(detail: str, cause: Exception = None) -> None:
+    """Raise a standardized 500 Internal Server Error exception.
+    
+    Args:
+        detail: Error message detail
+        cause: Optional underlying exception
+        
+    Raises:
+        HTTPException with 500 status code
+    """
+    if cause:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=detail,
+        ) from cause
+    else:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=detail,
+        )
+
+
+def raise_payment_required(detail: str = "Insufficient credits") -> None:
+    """Raise a standardized 402 Payment Required exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 402 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_402_PAYMENT_REQUIRED,
+        detail=detail,
+    )
+
+
+def raise_forbidden(detail: str = "Access forbidden") -> None:
+    """Raise a standardized 403 Forbidden exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 403 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_403_FORBIDDEN,
+        detail=detail,
+    )
+
+
+def raise_conflict(detail: str) -> None:
+    """Raise a standardized 409 Conflict exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 409 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_409_CONFLICT,
+        detail=detail,
+    )