We're in the process of moving from S3 to GCS and we've hit a snag: with boto S3 one can stream a download using the read method on a key, and stream an upload using multiple 'multipart' calls: initiate_multipart_upload, upload_part_from* and complete_upload.

It's imperfect, but this allows simple streaming uploads and downloads of very large files. Furthermore, stick some buffering in there and you can easily wrap S3 reads and writes into file-like objects (without seeking), like smart_open does.

I think that the API supports all the pieces necessary to implement this in the client (which would be greatly appreciated!), but in the meantime can anyone suggest a workaround which does not require a temporary file?

Thanks!