Fix cql2-text between operator (#521)

**Related Issue(s):**

- #513 

**Description:**

- Fix cql2-text between operator 

**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

Author: jonhealy1

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Fixed
 
+- Fixed "list index out of range" error when using BETWEEN operator in CQL2-text filters. [#521](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/521)
+
 ### Removed
 
 ### Updated

stac_fastapi/core/stac_fastapi/core/core.py

@@ -830,7 +830,7 @@ async def post_search(
                 search = await self.database.apply_cql2_filter(search, cql2_filter)
             except Exception as e:
                 raise HTTPException(
-                    status_code=400, detail=f"Error with cql2_json filter: {e}"
+                    status_code=400, detail=f"Error with cql2 filter: {e}"
                 )
 
         if hasattr(search_request, "q"):

stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/filter/transform.py

@@ -92,7 +92,19 @@ def to_es(queryables_mapping: Dict[str, Any], query: Dict[str, Any]) -> Dict[str
 
     elif query["op"] == AdvancedComparisonOp.BETWEEN:
         field = to_es_field(queryables_mapping, query["args"][0]["property"])
-        gte, lte = query["args"][1], query["args"][2]
+
+        # Handle both formats: [property, [lower, upper]] or [property, lower, upper]
+        if len(query["args"]) == 2 and isinstance(query["args"][1], list):
+            # Format: [{'property': '...'}, [lower, upper]]
+            gte, lte = query["args"][1][0], query["args"][1][1]
+        elif len(query["args"]) == 3:
+            # Format: [{'property': '...'}, lower, upper]
+            gte, lte = query["args"][1], query["args"][2]
+        else:
+            raise ValueError(
+                f"BETWEEN operator expects 2 or 3 args, got {len(query['args'])}"
+            )
+
         if isinstance(gte, dict) and "timestamp" in gte:
             gte = gte["timestamp"]
         if isinstance(lte, dict) and "timestamp" in lte:

stac_fastapi/tests/extensions/test_filter.py

@@ -410,7 +410,7 @@ async def test_search_filter_extension_in_no_list(app_client, ctx):
 
     assert resp.status_code == 400
     assert resp.json() == {
-        "detail": f"Error with cql2_json filter: Arg {product_id} is not a list"
+        "detail": f"Error with cql2 filter: Arg {product_id} is not a list"
     }
 
 
@@ -440,6 +440,24 @@ async def test_search_filter_extension_between(app_client, ctx):
     assert len(resp.json()["features"]) == 1
 
 
+@pytest.mark.asyncio
+async def test_search_filter_extension_between_get(app_client, ctx):
+    """Test BETWEEN operator with GET request using CQL2-text format."""
+    sun_elevation = ctx.item["properties"]["view:sun_elevation"]
+    lower_bound = sun_elevation - 0.01
+    upper_bound = sun_elevation + 0.01
+
+    # Use CQL2-text format for GET request
+    filter_expr = f"properties.view:sun_elevation BETWEEN {lower_bound} AND {upper_bound} AND id = '{ctx.item['id']}'"
+
+    resp = await app_client.get(
+        "/search", params={"filter": filter_expr, "filter_lang": "cql2-text"}
+    )
+
+    assert resp.status_code == 200
+    assert len(resp.json()["features"]) == 1
+
+
 @pytest.mark.asyncio
 async def test_search_filter_extension_isnull_post(app_client, ctx):
     # Test for a property that is not null