remove FieldsExtension check in StacApi (#725)

Author: vincentsarago

CHANGES.md

@@ -15,6 +15,7 @@
 * Removed the Filter Extension dependency from `AggregationExtensionPostRequest` and `AggregationExtensionGetRequest` [#716](https://github.com/stac-utils/stac-fastapi/pull/716)
 * Removed `pagination_extension` attribute in `stac_fastapi.api.app.StacApi`
 * Removed use of `pagination_extension` in `register_get_item_collection` function (User now need to construct the request model and pass it using `items_get_request_model` attribute)
+* Removed use of `FieldsExtension` in `stac_fastapi.api.app.StacApi`. If users use `FieldsExtension`, they would have to handle overpassing the model validation step by returning a `JSONResponse` from the `post_search` and `get_search` client methods.
 
 ### Changed
 

docs/src/migrations/v3.0.0.md

@@ -203,3 +203,67 @@ stac=StacApi(
     items_get_request_model=items_get_request_model,
 )
 ```
+
+
+## Fields extension and model validation
+
+When using the `Fields` extension, the `/search` endpoint should be able to return `**invalid** STAC Items. This creates an issue when *model validation* is enabled at the application level.
+
+Previously when adding the `FieldsExtension` to the extensions list and if setting output model validation, we were turning off the validation for both GET/POST `/search` endpoints. This was by-passing validation even when users were not using the `fields` options in requests.
+
+In `stac-fastapi` v3.0, implementers will have to by-pass the *validation step* at `Client` level by returning `JSONResponse` from the `post_search` and `get_search` client methods.
+
+```python
+# before
+class BadCoreClient(BaseCoreClient):
+    def post_search(
+        self, search_request: BaseSearchPostRequest, **kwargs
+    ) -> stac.ItemCollection:
+        return {"not": "a proper stac item"}
+
+    def get_search(
+        self,
+        collections: Optional[List[str]] = None,
+        ids: Optional[List[str]] = None,
+        bbox: Optional[List[NumType]] = None,
+        intersects: Optional[str] = None,
+        datetime: Optional[Union[str, datetime]] = None,
+        limit: Optional[int] = 10,
+        **kwargs,
+    ) -> stac.ItemCollection:
+        return {"not": "a proper stac item"}
+
+# now
+class BadCoreClient(BaseCoreClient):
+    def post_search(
+        self, search_request: BaseSearchPostRequest, **kwargs
+    ) -> stac.ItemCollection:
+        resp = {"not": "a proper stac item"}
+
+        # if `fields` extension is enabled, then we return a JSONResponse
+        # to avoid Item validation
+        if getattr(search_request, "fields", None):
+            return JSONResponse(content=resp)
+
+        return resp
+
+    def get_search(
+        self,
+        collections: Optional[List[str]] = None,
+        ids: Optional[List[str]] = None,
+        bbox: Optional[List[NumType]] = None,
+        intersects: Optional[str] = None,
+        datetime: Optional[Union[str, datetime]] = None,
+        limit: Optional[int] = 10,
+        **kwargs,
+    ) -> stac.ItemCollection:
+        resp = {"not": "a proper stac item"}
+
+        # if `fields` extension is enabled, then we return a JSONResponse
+        # to avoid Item validation
+        if "fields" in kwargs:
+            return JSONResponse(content=resp)
+
+        return resp
+
+```

stac_fastapi/api/stac_fastapi/api/app.py

@@ -27,9 +27,6 @@
 )
 from stac_fastapi.api.openapi import update_openapi
 from stac_fastapi.api.routes import Scope, add_route_dependencies, create_async_endpoint
-
-# TODO: make this module not depend on `stac_fastapi.extensions`
-from stac_fastapi.extensions.core import FieldsExtension
 from stac_fastapi.types.config import ApiSettings, Settings
 from stac_fastapi.types.core import AsyncBaseCoreClient, BaseCoreClient
 from stac_fastapi.types.extension import ApiExtension
@@ -225,15 +222,12 @@ def register_post_search(self):
         Returns:
             None
         """
-        fields_ext = self.get_extension(FieldsExtension)
         self.router.add_api_route(
             name="Search",
             path="/search",
-            response_model=(
-                (api.ItemCollection if not fields_ext else None)
-                if self.settings.enable_response_models
-                else None
-            ),
+            response_model=api.ItemCollection
+            if self.settings.enable_response_models
+            else None,
             responses={
                 200: {
                     "content": {
@@ -257,15 +251,12 @@ def register_get_search(self):
         Returns:
             None
         """
-        fields_ext = self.get_extension(FieldsExtension)
         self.router.add_api_route(
             name="Search",
             path="/search",
-            response_model=(
-                (api.ItemCollection if not fields_ext else None)
-                if self.settings.enable_response_models
-                else None
-            ),
+            response_model=api.ItemCollection
+            if self.settings.enable_response_models
+            else None,
             responses={
                 200: {
                     "content": {

stac_fastapi/api/stac_fastapi/api/models.py

@@ -1,6 +1,5 @@
 """Api request/response models."""
 
-import importlib.util
 from dataclasses import dataclass, make_dataclass
 from typing import List, Optional, Type, Union
 
@@ -19,6 +18,12 @@
     str_to_interval,
 )
 
+try:
+    import orjson  # noqa
+    from fastapi.responses import ORJSONResponse as JSONResponse
+except ImportError:  # pragma: nocover
+    from starlette.responses import JSONResponse
+
 
 def create_request_model(
     model_name="SearchGetRequest",
@@ -120,29 +125,13 @@ def __post_init__(self):
             self.datetime = str_to_interval(self.datetime)  # type: ignore
 
 
-# Test for ORJSON and use it rather than stdlib JSON where supported
-if importlib.util.find_spec("orjson") is not None:
-    from fastapi.responses import ORJSONResponse
-
-    class GeoJSONResponse(ORJSONResponse):
-        """JSON with custom, vendor content-type."""
-
-        media_type = "application/geo+json"
-
-    class JSONSchemaResponse(ORJSONResponse):
-        """JSON with custom, vendor content-type."""
-
-        media_type = "application/schema+json"
-
-else:
-    from starlette.responses import JSONResponse
+class GeoJSONResponse(JSONResponse):
+    """JSON with custom, vendor content-type."""
 
-    class GeoJSONResponse(JSONResponse):
-        """JSON with custom, vendor content-type."""
+    media_type = "application/geo+json"
 
-        media_type = "application/geo+json"
 
-    class JSONSchemaResponse(JSONResponse):
-        """JSON with custom, vendor content-type."""
+class JSONSchemaResponse(JSONResponse):
+    """JSON with custom, vendor content-type."""
 
-        media_type = "application/schema+json"
+    media_type = "application/schema+json"

stac_fastapi/api/tests/test_app.py

@@ -11,6 +11,7 @@
 from stac_fastapi.api import app
 from stac_fastapi.api.models import (
     APIRequest,
+    JSONResponse,
     create_get_request_model,
     create_post_request_model,
 )
@@ -206,7 +207,14 @@ class BadCoreClient(BaseCoreClient):
         def post_search(
             self, search_request: BaseSearchPostRequest, **kwargs
         ) -> stac.ItemCollection:
-            return {"not": "a proper stac item"}
+            resp = {"not": "a proper stac item"}
+
+            # if `fields` extension is enabled, then we return a JSONResponse
+            # to avoid Item validation
+            if getattr(search_request, "fields", None):
+                return JSONResponse(content=resp)
+
+            return resp
 
         def get_search(
             self,
@@ -218,7 +226,14 @@ def get_search(
             limit: Optional[int] = 10,
             **kwargs,
         ) -> stac.ItemCollection:
-            return {"not": "a proper stac item"}
+            resp = {"not": "a proper stac item"}
+
+            # if `fields` extension is enabled, then we return a JSONResponse
+            # to avoid Item validation
+            if "fields" in kwargs:
+                return JSONResponse(content=resp)
+
+            return resp
 
         def get_item(self, item_id: str, collection_id: str, **kwargs) -> stac.Item:
             raise NotImplementedError
@@ -240,6 +255,7 @@ def item_collection(
         ) -> stac.ItemCollection:
             raise NotImplementedError
 
+    # With FieldsExtension
     test_app = app.StacApi(
         settings=ApiSettings(enable_response_models=validate),
         client=BadCoreClient(),
@@ -264,14 +280,18 @@ def item_collection(
             },
         )
 
+    # With or without validation, /search endpoints will always return 200
+    # because we have the `FieldsExtension` enabled, so the endpoint
+    # will avoid the model validation (by returning JSONResponse)
     assert get_search.status_code == 200, get_search.text
     assert post_search.status_code == 200, post_search.text
 
+    # Without FieldsExtension
     test_app = app.StacApi(
         settings=ApiSettings(enable_response_models=validate),
         client=BadCoreClient(),
-        search_get_request_model=create_get_request_model([FieldsExtension()]),
-        search_post_request_model=create_post_request_model([FieldsExtension()]),
+        search_get_request_model=create_get_request_model([]),
+        search_post_request_model=create_post_request_model([]),
         extensions=[],
     )
 
@@ -290,7 +310,10 @@ def item_collection(
                 },
             },
         )
+
     if validate:
+        # NOTE: the `fields` options will be ignored by fastAPI because it's
+        # not part of the request model, so the client should not by-pass the validation
         assert get_search.status_code == 500, (
             get_search.json()["code"] == "ResponseValidationError"
         )