Feature Request: Support Text IO

[asford]

It would be valuable to support the standard Text I/O interface in gcsfs for use as a standalone, file-like library. The current behavior requires binary IO, which is not directly compatible with some standard tools (eg. json).

For example:

import json
import gcsfs

fs = gcsfs.GCSFileSystem(...)
an_obj = {"foo" : "bar"}

with fs.open("bucket/path", "w") as of:
    json.dump(an_obj, of)

raises NotImplementedError.

While it's possible to workaround via io.TextIOWrapper, it would be best to expose a GCSFile in text-mode in order to provide support for gcsfs-specific api extensions on the file object.

import json
import gcsfs

fs = gcsfs.GCSFileSystem(...)
an_obj = {"foo" : "bar"}

with fs.open("bucket/path", "wb') as of:
    json.dump(an_obj, io.TextIOWrapper(of))

[asford]

For clarity, particularly for anyone looking to use gcsfs alone, the dask.bytes.core.OpenFileCreator interface can be used to access this interface with under a TextIOWrapper.

[martindurant]

Certainly, seem easy enough to implement should 'b' should not be in the mode, I guess within GCSFileSystem.open rather than GCSFile.__init__?
Note that there is already some similar logic in dask.bytes.core.OpenFile, used, for instance, by dak.bag.to_textfile.