Function test_callable_spec

cherrypy/_cpdispatch.py:66–199

Inspect callable and test to see if the given args are suitable for it. When an error occurs during the handler's invoking stage there are 2 erroneous cases: 1. Too many parameters passed to a function which doesn't define one of *args or **kwargs. 2. Too little parameters

(callable, callable_args, callable_kwargs)

def test_callable_spec(callable, callable_args, callable_kwargs):
    """Inspect callable and test to see if the given args are suitable for it.

    When an error occurs during the handler's invoking stage there are 2
    erroneous cases:
    1.  Too many parameters passed to a function which doesn't define
        one of *args or **kwargs.
    2.  Too little parameters are passed to the function.

    There are 3 sources of parameters to a cherrypy handler.
    1.  query string parameters are passed as keyword parameters to the
        handler.
    2.  body parameters are also passed as keyword parameters.
    3.  when partial matching occurs, the final path atoms are passed as
        positional args.
    Both the query string and path atoms are part of the URI.  If they are
    incorrect, then a 404 Not Found should be raised. Conversely the body
    parameters are part of the request; if they are invalid a 400 Bad Request.
    """
    show_mismatched_params = getattr(
        cherrypy.serving.request, 'show_mismatched_params', False)
    try:
        (args, varargs, varkw, defaults) = getargspec(callable)
    except TypeError:
        if isinstance(callable, object) and hasattr(callable, '__call__'):
            (args, varargs, varkw,
             defaults) = getargspec(callable.__call__)
        else:
            # If it wasn't one of our own types, re-raise
            # the original error
            raise

    if args and (
            # For callable objects, which have a __call__(self) method
            hasattr(callable, '__call__') or
            # For normal methods
            inspect.ismethod(callable)
    ):
        # Strip 'self'
        args = args[1:]

    arg_usage = dict([(arg, 0,) for arg in args])
    vararg_usage = 0
    varkw_usage = 0
    extra_kwargs = set()

    for i, value in enumerate(callable_args):
        try:
            arg_usage[args[i]] += 1
        except IndexError:
            vararg_usage += 1

    for key in callable_kwargs.keys():
        try:
            arg_usage[key] += 1
        except KeyError:
            varkw_usage += 1
            extra_kwargs.add(key)