Add field exclusion from queryables endpoint. (#489)

**Description:**
added `EXCLUDED_FROM_QUERYABLES` environment variable to allow excluding
specific fields from the queryables endpoint and filtering, even if
those are indexed. Supports comma-separated list of fully qualified
field names (e.g., properties.auth:schemes,properties.storage:schemes).

**PR Checklist:**

- [x] Code is formatted and linted (run `pre-commit run --all-files`)
- [x] Tests pass (run `make test`)
- [x] Documentation has been updated to reflect changes, if applicable
- [x] Changes are added to the changelog

---------

Co-authored-by: Jonathan Healy <jonathan.d.healy@gmail.com>

Author: MathewNWSH

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
 
+- CloudFerro logo to sponsors and supporters list [#485](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/485)
+- Latest news section to README [#485](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/485)
+- Environment variable `EXCLUDED_FROM_QUERYABLES` to exclude specific fields from queryables endpoint and filtering. Supports comma-separated list of fully qualified field names (e.g., `properties.auth:schemes,properties.storage:schemes`) [#489](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/489)
+
 ### Changed
 
 ### Fixed

README.md

@@ -102,6 +102,7 @@ This project is built on the following technologies: STAC, stac-fastapi, FastAPI
       - [Using Pre-built Docker Images](#using-pre-built-docker-images)
       - [Using Docker Compose](#using-docker-compose)
   - [Configuration Reference](#configuration-reference)
+  - [Excluding Fields from Queryables](#excluding-fields-from-queryables)
   - [Datetime-Based Index Management](#datetime-based-index-management)
     - [Overview](#overview)
     - [When to Use](#when-to-use)
@@ -337,10 +338,35 @@ You can customize additional settings in your `.env` file:
 | `STAC_DEFAULT_ITEM_LIMIT` | Configures the default number of STAC items returned when no limit parameter is specified in the request. | `10` | Optional |
 | `STAC_INDEX_ASSETS` | Controls if Assets are indexed when added to Elasticsearch/Opensearch. This allows asset fields to be included in search queries. | `false` | Optional |
 | `USE_DATETIME` | Configures the datetime search behavior in SFEOS. When enabled, searches both datetime field and falls back to start_datetime/end_datetime range for items with null datetime. When disabled, searches only by start_datetime/end_datetime range. | `true` | Optional |
+| `EXCLUDED_FROM_QUERYABLES` | Comma-separated list of fully qualified field names to exclude from the queryables endpoint and filtering. Use full paths like `properties.auth:schemes,properties.storage:schemes`. Excluded fields and their nested children will not be exposed in queryables. | None | Optional |
 
 > [!NOTE]
 > The variables `ES_HOST`, `ES_PORT`, `ES_USE_SSL`, `ES_VERIFY_CERTS` and `ES_TIMEOUT` apply to both Elasticsearch and OpenSearch backends, so there is no need to rename the key names to `OS_` even if you're using OpenSearch.
 
+## Excluding Fields from Queryables
+
+You can exclude specific fields from being exposed in the queryables endpoint and from filtering by setting the `EXCLUDED_FROM_QUERYABLES` environment variable. This is useful for hiding sensitive or internal fields that should not be queryable by API users.
+
+**Environment Variable:**
+
+```bash
+EXCLUDED_FROM_QUERYABLES="properties.auth:schemes,properties.storage:schemes,properties.internal:metadata"
+```
+
+**Format:**
+
+- Comma-separated list of fully qualified field names
+- Use the full path including the `properties.` prefix for item properties
+- Example field names:
+  - `properties.auth:schemes`
+  - `properties.storage:schemes`
+
+**Behavior:**
+
+- Excluded fields will not appear in the queryables response
+- Excluded fields and their nested children will be skipped during field traversal
+- Both the field itself and any nested properties will be excluded
+
 ## Datetime-Based Index Management
 
 ### Overview

stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter/README.md

@@ -9,10 +9,12 @@ between the two implementations.
 The filter package is organized into three main modules:
 
 - **cql2.py**: Contains functions for converting CQL2 patterns to Elasticsearch/OpenSearch compatible formats
+
   - [cql2_like_to_es](cci:1://file:///home/computer/Code/stac-fastapi-elasticsearch-opensearch/stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter.py:59:0-75:5): Converts CQL2 "LIKE" characters to Elasticsearch "wildcard" characters
-  - [_replace_like_patterns](cci:1://file:///home/computer/Code/stac-fastapi-elasticsearch-opensearch/stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter.py:51:0-56:71): Helper function for pattern replacement
+  - [\_replace_like_patterns](cci:1://file:///home/computer/Code/stac-fastapi-elasticsearch-opensearch/stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter.py:51:0-56:71): Helper function for pattern replacement
 
 - **transform.py**: Contains functions for transforming CQL2 queries to Elasticsearch/OpenSearch query DSL
+
   - [to_es_field](cci:1://file:///home/computer/Code/stac-fastapi-elasticsearch-opensearch/stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter.py:83:0-93:47): Maps field names using queryables mapping
   - [to_es](cci:1://file:///home/computer/Code/stac-fastapi-elasticsearch-opensearch/stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter.py:96:0-201:13): Transforms CQL2 query structures to Elasticsearch/OpenSearch query DSL
 
@@ -24,4 +26,5 @@ The filter package is organized into three main modules:
 Import the necessary components from the filter package:
 
 ```python
-from stac_fastapi.sfeos_helpers.filter import cql2_like_to_es, to_es, EsAsyncBaseFiltersClient
+from stac_fastapi.sfeos_helpers.filter import cql2_like_to_es, to_es, EsAsyncBaseFiltersClient
+```

stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter/client.py

@@ -1,7 +1,8 @@
 """Filter client implementation for Elasticsearch/OpenSearch."""
 
+import os
 from collections import deque
-from typing import Any, Dict, Optional, Tuple
+from typing import Any, Optional
 
 import attr
 from fastapi import Request
@@ -18,9 +19,29 @@ class EsAsyncBaseFiltersClient(AsyncBaseFiltersClient):
 
     database: BaseDatabaseLogic = attr.ib()
 
+    @staticmethod
+    def _get_excluded_from_queryables() -> set[str]:
+        """Get fields to exclude from queryables endpoint and filtering.
+
+        Reads from EXCLUDED_FROM_QUERYABLES environment variable.
+        Supports comma-separated list of field names.
+
+        Example:
+            EXCLUDED_FROM_QUERYABLES="auth:schemes,storage:schemes"
+
+        Returns:
+            Set[str]: Set of field names to exclude from queryables
+        """
+        excluded = os.getenv("EXCLUDED_FROM_QUERYABLES", "")
+        if not excluded:
+            return set()
+        return {field.strip() for field in excluded.split(",") if field.strip()}
+
     async def get_queryables(
-        self, collection_id: Optional[str] = None, **kwargs
-    ) -> Dict[str, Any]:
+        self,
+        collection_id: Optional[str] = None,  # noqa: UP045
+        **kwargs: Any,
+    ) -> dict[str, Any]:
         """Get the queryables available for the given collection_id.
 
         If collection_id is None, returns the intersection of all
@@ -38,21 +59,23 @@ async def get_queryables(
         Returns:
             Dict[str, Any]: A dictionary containing the queryables for the given collection.
         """
-        request: Optional[Request] = kwargs.get("request")
-        url_str: str = str(request.url) if request else ""
-        queryables: Dict[str, Any] = {
+        request: Optional[Request] = kwargs.get("request")  # noqa: UP045
+        url_str = str(request.url) if request else ""
+
+        queryables: dict[str, Any] = {
             "$schema": "https://json-schema.org/draft-07/schema",
-            "$id": f"{url_str}",
+            "$id": url_str,
             "type": "object",
             "title": "Queryables for STAC API",
             "description": "Queryable names for the STAC API Item Search filter.",
             "properties": DEFAULT_QUERYABLES,
             "additionalProperties": True,
         }
+
         if not collection_id:
             return queryables
 
-        properties: Dict[str, Any] = queryables["properties"].copy()
+        properties = queryables["properties"].copy()
         queryables.update(
             {
                 "properties": properties,
@@ -62,8 +85,9 @@ async def get_queryables(
 
         mapping_data = await self.database.get_items_mapping(collection_id)
         mapping_properties = next(iter(mapping_data.values()))["mappings"]["properties"]
-        stack: deque[Tuple[str, Dict[str, Any]]] = deque(mapping_properties.items())
-        enum_fields: Dict[str, Dict[str, Any]] = {}
+        stack: deque[tuple[str, dict[str, Any]]] = deque(mapping_properties.items())
+        enum_fields: dict[str, dict[str, Any]] = {}
+        excluded_fields = self._get_excluded_from_queryables()
 
         while stack:
             field_fqn, field_def = stack.popleft()
@@ -75,11 +99,16 @@ async def get_queryables(
                     (f"{field_fqn}.{k}", v)
                     for k, v in field_properties.items()
                     if v.get("enabled", True)
+                    and f"{field_fqn}.{k}" not in excluded_fields
                 )
 
             # Skip non-indexed or disabled fields
             field_type = field_def.get("type")
-            if not field_type or not field_def.get("enabled", True):
+            if (
+                not field_type
+                or not field_def.get("enabled", True)
+                or field_fqn in excluded_fields
+            ):
                 continue
 
             # Fields in Item Properties should be exposed with their un-prefixed names,
@@ -88,7 +117,7 @@ async def get_queryables(
             field_name = field_fqn.removeprefix("properties.")
 
             # Generate field properties
-            field_result = ALL_QUERYABLES.get(field_name, {})
+            field_result = ALL_QUERYABLES.get(field_name, {}).copy()
             properties[field_name] = field_result
 
             field_name_human = field_name.replace("_", " ").title()
@@ -104,9 +133,10 @@ async def get_queryables(
                 enum_fields[field_fqn] = field_result
 
         if enum_fields:
-            for field_fqn, unique_values in (
-                await self.database.get_items_unique_values(collection_id, enum_fields)
-            ).items():
-                enum_fields[field_fqn]["enum"] = unique_values
+            unique_values = await self.database.get_items_unique_values(
+                collection_id, enum_fields
+            )
+            for field_fqn, values in unique_values.items():
+                enum_fields[field_fqn]["enum"] = values
 
         return queryables

stac_fastapi/tests/extensions/test_filter.py

@@ -674,3 +674,53 @@ async def test_queryables_enum_platform(
     # Clean up
     r = await app_client.delete(f"/collections/{collection_id}")
     r.raise_for_status()
+
+
+@pytest.mark.asyncio
+async def test_queryables_excluded_fields(
+    app_client: AsyncClient,
+    load_test_data: Callable[[str], Dict],
+    monkeypatch: pytest.MonkeyPatch,
+):
+    """Test that fields can be excluded from queryables using EXCLUDED_FROM_QUERYABLES."""
+    # Arrange
+    monkeypatch.setenv("DATABASE_REFRESH", "true")
+    monkeypatch.setenv(
+        "EXCLUDED_FROM_QUERYABLES", "properties.platform,properties.instrument"
+    )
+
+    # Create collection
+    collection_data = load_test_data("test_collection.json")
+    collection_id = collection_data["id"] = f"exclude-test-collection-{uuid.uuid4()}"
+    r = await app_client.post("/collections", json=collection_data)
+    r.raise_for_status()
+
+    # Create an item
+    item_data = load_test_data("test_item.json")
+    item_data["id"] = "exclude-test-item"
+    item_data["collection"] = collection_id
+    item_data["properties"]["platform"] = "landsat-8"
+    item_data["properties"]["instrument"] = "OLI_TIRS"
+    r = await app_client.post(f"/collections/{collection_id}/items", json=item_data)
+    r.raise_for_status()
+
+    # Act
+    queryables = (
+        (await app_client.get(f"/collections/{collection_id}/queryables"))
+        .raise_for_status()
+        .json()
+    )
+
+    # Assert
+    # Excluded fields should NOT be in queryables
+    properties = queryables["properties"]
+    assert "platform" not in properties
+    assert "instrument" not in properties
+
+    # Other fields should still be present
+    assert "datetime" in properties
+    assert "gsd" in properties
+
+    # Clean up
+    r = await app_client.delete(f"/collections/{collection_id}")
+    r.raise_for_status()