import string import sys from django.utils.crypto import get_random_string def generate_access_code(): ''' Generates an access code for users' payments as well as their fulfilment code for check-in. The access code will 4 characters long, which allows for 1,500,625 unique codes, which really should be enough for anyone. ''' length = 6 # all upper-case letters + digits 1-9 (no 0 vs O confusion) chars = string.ascii_uppercase + string.digits[1:] # 6 chars => 35 ** 6 = 1838265625 (should be enough for anyone) return get_random_string(length=length, allowed_chars=chars) def all_arguments_optional(ntcls): ''' Takes a namedtuple derivative and makes all of the arguments optional. ''' ntcls.__new__.__defaults__ = ( (None,) * len(ntcls._fields) ) return ntcls def lazy(function, *args, **kwargs): ''' Produces a callable so that functions can be lazily evaluated in templates. Arguments: function (callable): The function to call at evaluation time. args: Positional arguments, passed directly to ``function``. kwargs: Keyword arguments, passed directly to ``function``. Return: callable: A callable that will evaluate a call to ``function`` with the specified arguments. ''' NOT_EVALUATED = object() retval = [NOT_EVALUATED] def evaluate(): if retval[0] is NOT_EVALUATED: retval[0] = function(*args, **kwargs) return retval[0] return evaluate def get_object_from_name(name): ''' Returns the named object. Arguments: name (str): A string of form `package.subpackage.etc.module.property`. This function will import `package.subpackage.etc.module` and return `property` from that module. ''' dot = name.rindex(".") mod_name, property_name = name[:dot], name[dot + 1:] __import__(mod_name) return getattr(sys.modules[mod_name], property_name)