utils.py 文件源码

def web2py_uuid(ctokens=UNPACKED_CTOKENS):
    """
    This function follows from the following discussion:
    `http://groups.google.com/group/web2py-developers/browse_thread/thread/7fd5789a7da3f09`

    It works like uuid.uuid4 except that tries to use os.urandom() if possible
    and it XORs the output with the tokens uniquely associated with this machine.
    """
    rand_longs = (random.getrandbits(64), random.getrandbits(64))
    if HAVE_URANDOM:
        urand_longs = _struct_2_long_long.unpack(fast_urandom16())
        byte_s = _struct_2_long_long.pack(rand_longs[0] ^ urand_longs[0] ^ ctokens[0],
                                          rand_longs[1] ^ urand_longs[1] ^ ctokens[1])
    else:
        byte_s = _struct_2_long_long.pack(rand_longs[0] ^ ctokens[0],
                                          rand_longs[1] ^ ctokens[1])
    return str(uuid.UUID(bytes=byte_s, version=4))