UnpackRequest - method

import inspect


class WrongParameter(Exception):

    def __init__(self, parameter_name):
        self.parameter_name = parameter_name

    def __str__(self):
        return self.parameter_name


def get_avalible_args(request):
    return {
        'request': request,
        'POST': request.POST,
        'GET': request.GET,
        'matchdict': request.matchdict,
        'db': request.db,
        'settings': request.registry['settings'],
        'session': request.session,
        'user': request.user,
    }


def get_kwargs(avalible_args, fun_args):
    fun_kwargs = {}
    for key in fun_args:
        try:
            fun_kwargs[key] = avalible_args[key]
        except KeyError:
            raise WrongParameter(key)
    return fun_kwargs


def UnpackRequest(fun):
    def wraper(request):
        fun_args = inspect.getargspec(fun).args
        avalible_args = get_avalible_args(request)
        fun_kwargs = get_kwargs(avalible_args, fun_args)
        return fun(**fun_kwargs)
    return wraper