fix: ensure min, max dates have correct format (#539)

**Description:**

Currently, the `min` and `max` dates used in `apply_datetime_filter` for
`POST` requests are not formatted correctly. This PR fixes the issue:
```
{"code":"ParserError","description":"Unknown string format: 2262-04-11T23:47:16.854775+00:00Z"}
```

**PR Checklist:**

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

---------

Co-authored-by: Yuri Zmytrakov <yzmytrakovNB@yzmytrakovNB.local>

Author: YuriZmytrakov

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Fixed
 
+- Fix incorrect min/max date formatting in `apply_datetime_filter` for `POST` requests. [#539](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/539)
 - Fixed datetime filtering for .0Z milliseconds to preserve precision in apply_filter_datetime, ensuring only items exactly within the specified range are returned. [#535](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/535)
 - Normalize datetime in POST /search requests to match GET /search behavior. [#543](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/543)
 

stac_fastapi/sfeos_helpers/stac_fastapi/sfeos_helpers/database/datetime.py

@@ -53,12 +53,12 @@ def return_date(
             if "/" in interval:
                 parts = interval.split("/")
                 result["gte"] = (
-                    parts[0] if parts[0] != ".." else MIN_DATE_NANOS.isoformat() + "Z"
+                    parts[0] if parts[0] != ".." else MIN_DATE_NANOS.isoformat()
                 )
                 result["lte"] = (
                     parts[1]
                     if len(parts) > 1 and parts[1] != ".."
-                    else MAX_DATE_NANOS.isoformat() + "Z"
+                    else MAX_DATE_NANOS.isoformat()
                 )
             else:
                 converted_time = interval if interval != ".." else None
@@ -75,7 +75,7 @@ def return_date(
                 dt_utc = MIN_DATE_NANOS
             elif dt_utc > MAX_DATE_NANOS:
                 dt_utc = MAX_DATE_NANOS
-            datetime_iso = dt_utc.isoformat()
+            datetime_iso = dt_utc.isoformat().replace("+00:00", "Z")
             result["gte"] = result["lte"] = datetime_iso
         elif isinstance(interval, tuple):
             start, end = interval
@@ -90,7 +90,7 @@ def return_date(
                     start_utc = MIN_DATE_NANOS
                 elif start_utc > MAX_DATE_NANOS:
                     start_utc = MAX_DATE_NANOS
-                result["gte"] = start_utc.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+                result["gte"] = start_utc.isoformat().replace("+00:00", "Z")
             if end:
                 end_utc = (
                     end.astimezone(timezone.utc)
@@ -101,7 +101,7 @@ def return_date(
                     end_utc = MIN_DATE_NANOS
                 elif end_utc > MAX_DATE_NANOS:
                     end_utc = MAX_DATE_NANOS
-                result["lte"] = end_utc.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+                result["lte"] = end_utc.isoformat().replace("+00:00", "Z")
 
         return result
 
@@ -131,9 +131,9 @@ def return_date(
             start, end = interval
             # Ensure datetimes are converted to UTC and formatted with 'Z'
             if start:
-                result["gte"] = start.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+                result["gte"] = start.isoformat().replace("+00:00", "Z")
             if end:
-                result["lte"] = end.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+                result["lte"] = end.isoformat().replace("+00:00", "Z")
 
         return result