update readers to match new file structure

virtualizarr/backend.py

@@ -7,20 +7,27 @@
     Any,
     Hashable,
     Optional,
+    TypeAlias,
     cast,
 )
 
 import xarray as xr
 from xarray.backends import AbstractDataStore, BackendArray
 from xarray.coding.times import CFDatetimeCoder
+from xarray.conventions import decode_cf_variables
 from xarray.core.indexes import Index, PandasIndex
-from xarray.core.variable import IndexVariable
+from xarray.core.variable import IndexVariable, Variable
 
 from virtualizarr.manifests import ManifestArray
 from virtualizarr.utils import _fsspec_openfile_from_filepath
 
 XArrayOpenT = str | os.PathLike[Any] | BufferedIOBase | AbstractDataStore
 
+T_Attrs = MutableMapping[Any, Any]
+T_Variables = Mapping[Any, Variable]
+# alias for (dims, data, attrs, encoding)
+T_VariableExpanded: TypeAlias = tuple[Hashable, Any, dict[Any, Any], dict[Any, Any]]
+
 
 class AutoName(Enum):
     # Recommended by official Python docs for auto naming:

virtualizarr/readers/kerchunk.py

@@ -7,7 +7,11 @@
 from xarray.core.indexes import Index
 from xarray.core.variable import Variable
 
-from virtualizarr.backend import FileType, separate_coords
+from virtualizarr.backend import (
+    FileType,
+    construct_virtual_dataset,
+    determine_cf_coords,
+)
 from virtualizarr.manifests import ChunkManifest, ManifestArray
 from virtualizarr.types.kerchunk import (
     KerchunkArrRefs,
@@ -176,14 +180,10 @@ def dataset_from_kerchunk_refs(
 
     if indexes is None:
         indexes = {}
-    data_vars, coords = separate_coords(vars, indexes, coord_names)
 
-    vds = Dataset(
-        data_vars,
-        coords=coords,
-        # indexes={},  # TODO should be added in a later version of xarray
-        attrs=ds_attrs,
-    )
+    decoded_vars, decoded_attrs, coord_names = determine_cf_coords(vars, ds_attrs)
+
+    vds = construct_virtual_dataset(decoded_vars, indexes, decoded_attrs, coord_names)
 
     return vds
 

virtualizarr/readers/zarr.py

@@ -8,7 +8,7 @@
 from xarray.core.indexes import Index
 from xarray.core.variable import Variable
 
-from virtualizarr.backend import determine_cf_coords, construct_virtual_dataset
+from virtualizarr.backend import construct_virtual_dataset, determine_cf_coords
 from virtualizarr.manifests import ChunkManifest, ManifestArray
 from virtualizarr.zarr import ZArray