def dumps(obj, key=None, salt='django.core.signing', serializer=JSONSerializer, compress=False):
    """
    Returns URL-safe, sha1 signed base64 compressed JSON string. If key is
    None, settings.SECRET_KEY is used instead.

    If compress is True (not the default) checks if compressing using zlib can
    save some space. Prepends a '.' to signify compression. This is included
    in the signature, to protect against zip bombs.

    Salt can be used to namespace the hash, so that a signed string is
    only valid for a given namespace. Leaving this at the default
    value or re-using a salt value across different parts of your
    application without good cause is a security risk.

    The serializer is expected to return a bytestring.
    """
    data = serializer().dumps(obj)

    # Flag for if it's been compressed or not
    is_compressed = False

    if compress:
        # Avoid zlib dependency unless compress is being used
        compressed = zlib.compress(data)
        if len(compressed) < (len(data) - 1):
            data = compressed
            is_compressed = True
    base64d = b64_encode(data)
    if is_compressed:
        base64d = b'.' + base64d
    return TimestampSigner(key, salt=salt).sign(base64d)
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/core/signing.py/dumps/original