Harden DHMV WCS request headers

backend/app/services/dhmv_acquisition_service.py

@@ -279,7 +279,13 @@ class DhmvAcquisitionService:
 
     @staticmethod
     def _fetch(request_url: str, settings: Settings, opener: Callable[..., Any] | None = None) -> tuple[bytes, str]:
-        request = Request(request_url, headers={"User-Agent": "GeoIntel/0.1 bounded-dhmv-acquisition"})
+        request = Request(
+            request_url,
+            headers={
+                "Accept": "*/*",
+                "User-Agent": "GeoIntel/0.1 bounded-dhmv-acquisition",
+            },
+        )
         max_bytes = settings.dhmv_max_response_mb * 1024 * 1024
         try:
             with (opener or urlopen)(request, timeout=settings.dhmv_timeout_seconds) as response:

backend/tests/test_sprint205_dhmv_terrain.py

@@ -200,6 +200,28 @@ def test_dhmv_multipart_geotiff_is_extracted_and_invalid_response_fails_closed()
     assert exc_info.value.code == "DHMV_PROVIDER_INVALID_RESPONSE"
 
 
+def test_dhmv_fetch_sends_explicit_accept_header_required_by_official_wcs() -> None:
+    observed_headers: dict[str, str | None] = {}
+
+    def opener(request, **_kwargs):
+        observed_headers["accept"] = request.get_header("Accept")
+        observed_headers["user_agent"] = request.get_header("User-agent")
+        return FakeResponse(b"II*\x00test", "image/tiff")
+
+    content, content_type = DhmvAcquisitionService._fetch(
+        "https://geo.api.vlaanderen.be/DHMV/wcs?bounded=true",
+        Settings(_env_file=None),
+        opener,
+    )
+
+    assert content == b"II*\x00test"
+    assert content_type == "image/tiff"
+    assert observed_headers == {
+        "accept": "*/*",
+        "user_agent": "GeoIntel/0.1 bounded-dhmv-acquisition",
+    }
+
+
 def test_dhmv_acquisition_clips_validates_and_persists_via_dataset_service(tmp_path) -> None:
     project_id = uuid4()
     area_id = uuid4()