allow CRS as URIs (#81)

src/django_oapif/decorators.py

@@ -1,3 +1,4 @@
+import re
 from os import getenv
 from typing import Any, Callable, Dict, Optional
 
@@ -13,6 +14,59 @@
 
 from .filters import BboxFilterBackend
 
+# taken from https://github.com/geopython/pygeoapi/blob/953b6fa74d2ce292d8f566c4f4d3bcb4161d6e95/pygeoapi/util.py#L90
+CRS_AUTHORITY = [
+ "AUTO",
+ "EPSG",
+ "OGC",
+]
+
+CRS_URI_PATTERN = re.compile(
+ (
+ rf"^http://www.opengis\.net/def/crs/"
+ rf"(?P<auth>{'|'.join(CRS_AUTHORITY)})/"
+ rf"[\d|\.]+?/(?P<code>\w+?)$"
+ )
+)
+
+
+# taken from
+def get_crs_from_uri(uri: str) -> CRS:
+ """
+ Get a `pyproj.CRS` instance from a CRS URI.
+ Author: @MTachon
+
+ :param uri: Uniform resource identifier of the coordinate
+ reference system.
+ :type uri: str
+
+ :raises `CRSError`: Error raised if no CRS could be identified from the
+ URI.
+
+ :returns: `pyproj.CRS` instance matching the input URI.
+ :rtype: `pyproj.CRS`
+ """
+
+ try:
+ crs = CRS.from_authority(*CRS_URI_PATTERN.search(uri).groups())
+ except RuntimeError:
+ msg = (
+ f"CRS could not be identified from URI {uri!r} "
+ f"(Authority: {CRS_URI_PATTERN.search(uri).group('auth')!r}, "
+ f"Code: {CRS_URI_PATTERN.search(uri).group('code')!r})."
+ )
+ raise RuntimeError(msg)
+ except AttributeError:
+ msg = (
+ f"CRS could not be identified from URI {uri!r}. CRS URIs must "
+ "follow the format "
+ "'http://www.opengis.net/def/crs/{authority}/{version}/{code}' "
+ "(see https://docs.opengeospatial.org/is/18-058r1/18-058r1.html#crs-overview)." # noqa
+ )
+ raise AttributeError(msg)
+ else:
+ return crs
+
 
 def register_oapif_viewset(
  key: Optional[str] = None,
@@ -89,16 +143,18 @@ def get_queryset(self):
 
  if user_crs:
  try:
- crs_epsg = int(user_crs)
- except ValueError:
+ user_crs = get_crs_from_uri(user_crs)
+ except:
  return HttpResponseBadRequest(
  "This API supports only EPSG-specified CRS. Make sure to use the appropriate value for the `bbox-crs`query parameter."
  )
- user_crs = CRS.from_epsg(crs_epsg)
  api_crs = CRS.from_epsg(int(getenv("GEOMETRY_SRID", "2056")))
  transformer = Transformer.from_crs(user_crs, api_crs)
- transformed_coords = transformer.transform(coords)
- my_bbox_polygon = Polygon.from_bbox(transformed_coords)
+ LL = transformer.transform(coords[0], coords[1])
+ UR = transformer.transform(coords[2], coords[3])
+ my_bbox_polygon = Polygon.from_bbox(
+ [LL[0], LL[1], UR[0], UR[1]]
+ )
 
  else:
  my_bbox_polygon = Polygon.from_bbox(coords)