tar_manifest.py

import base64
import json
import tarfile
import time


files = {
    'c/o': {'name': 'tox.ini', 'size': 3935},
    'c/o2': {'name': 'setup.cfg', 'size': 4396}
}


def tar_padding(sz):
    _bs = tarfile.BLOCKSIZE
    return '\x00' * (_bs - (sz - 1) % _bs - 1)


def tar_header(v):
    info = tarfile.TarInfo(name=v['name'])
    info.size = v['size']
    info.type = tarfile.REGTYPE
    info.mode = 0664
    info.mtime = time.time()
    return info.tobuf(format=tarfile.GNU_FORMAT)


print json.dumps([{
    'path': k,
    'preamble': base64.b64encode(tar_header(v)),
    'postamble': base64.b64encode(tar_padding(v['size']))
} for k, v in files.items()] + [{'path': 'c/__end_tar'}])