add methods to GET/PUT file attachments

[jevonearth]

frappe-client doesn't have methods to fetch attachments for a given document. The meta data is available using get_doc as shown below.

    return wn.get_doc(
            'File Data',
            filters=[
                ['File Data', 'attached_to_doctype', '=', doctype],
                ['File Data', 'attached_to_name', '=', docname]],
            fields=['name','file_name','file_url', 'file_size'])

Methods to fetch and post attachments would be very useful.

[MaxMorais]

@jevonearth, do you need this? I can release in https://github.com/frappe/frappe-client/pull/12

[jevonearth]

Oh yes, this will be super helpful. Thanks @MaxMorais !

[MaxMorais]

@jevonearth, can you describe the functions that do you need?

Attachment upload Attachment download Attachment delete

Other?

[jevonearth]

Can't think of any, I think we can already list attachments.

If there are many attachments, do you favour that the caller just requests each by iterating on the attachment list?