fix archive_to_fdb (#130)

- io.BytesIO is missing the raw attribute
- pyfdb should be an optional dependency of idpi

src/idpi/grib_decoder.py

@@ -344,7 +344,11 @@ def load_fieldnames(
  return self.load(reqs, extract_pv)
 
 
-def save(field: xr.DataArray, file_handle: io.BufferedWriter, bits_per_value: int = 16):
+def save(
+ field: xr.DataArray,
+ file_handle: io.BufferedWriter | io.BytesIO,
+ bits_per_value: int = 16,
+):
  """Write field to file in GRIB format.
 
  Parameters

src/idpi/mch_model_data.py

@@ -11,7 +11,6 @@
 import os
 
 # Third-party
-import pyfdb # type: ignore
 import xarray as xr
 
 # Local
@@ -116,9 +115,11 @@ def archive_to_fdb(
  Bits per value encoded in the archived data. (Default: 16)
 
  """
+ # Third-party
+ import pyfdb # type: ignore
+
  buffer = io.BytesIO()
- handle = io.BufferedWriter(buffer.raw)
- grib_decoder.save(field, handle, bits_per_value)
+ grib_decoder.save(field, buffer, bits_per_value)
  fdb = pyfdb.FDB()
  req = request.to_fdb() if request is not None else None
  if request is not None: