How to use the cherrypy.serving.request function in CherryPy

def __enter__(self):
        """Populate request.toolmaps from tools specified in config."""
        cherrypy.serving.request.toolmaps[self.namespace] = map = {}

        def populate(k, v):
            toolname, arg = k.split('.', 1)
            bucket = map.setdefault(toolname, {})
            bucket[arg] = v
        return populate

def request_namespace(k, v):
    """Attach request attributes declared in config."""
    # Provides config entries to set request.body attrs (like
    # attempt_charsets).
    if k[:5] == 'body.':
        setattr(cherrypy.serving.request.body, k[5:], v)
    else:
        setattr(cherrypy.serving.request, k, v)

self.

        CherryPy uses this internally, but you can also use it to create an
        HTTPError object and set its output without *raising* the exception.
        """
        import cherrypy

        response = cherrypy.serving.response

        clean_headers(self.code)

        # In all cases, finalize will be called after this method,
        # so don't bother cleaning up response values here.
        response.status = self.status
        tb = None
        if cherrypy.serving.request.show_tracebacks:
            tb = format_exc()

        response.headers.pop('Content-Length', None)

        content = self.get_error_page(self.status, traceback=tb,
                                      message=self._message)
        response.body = content

        _be_ie_unfriendly(self.code)

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) = inspect.getargspec(callable)
    except TypeError:
        if isinstance(callable, object) and hasattr(callable, '__call__'):
            (args, varargs, varkw,
             defaults) = inspect.getargspec(callable.__call__)
        else:
            # If it wasn't one of our own types, re-raise
            # the original error
            raise

    if args and args[0] == 'self':
        args = args[1:]

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

def request_namespace(k, v):
    """Attach request attributes declared in config."""
    # Provides config entries to set request.body attrs (like attempt_charsets).
    if k[:5] == 'body.':
        setattr(cherrypy.serving.request.body, k[5:], v)
    else:
        setattr(cherrypy.serving.request, k, v)

# We can't actually tell which case it is,
        # so I'm raising a 404 because that covers 2/3 of the
        # possibilities
        #
        # In the case where the method does not allow body
        # arguments it's definitely a 404.
        message = None
        if show_mismatched_params:
            message = "Missing parameters: %s" % ",".join(missing_args)
        raise cherrypy.HTTPError(404, message=message)

    # the extra positional arguments come from the path - 404 Not Found
    if not varargs and vararg_usage > 0:
        raise cherrypy.HTTPError(404)

    body_params = cherrypy.serving.request.body.params or {}
    body_params = set(body_params.keys())
    qs_params = set(callable_kwargs.keys()) - body_params

    if multiple_args:
        if qs_params.intersection(set(multiple_args)):
            # If any of the multiple parameters came from the query string then
            # it's a 404 Not Found
            error = 404
        else:
            # Otherwise it's a 400 Bad Request
            error = 400

        message = None
        if show_mismatched_params:
            message = "Multiple values for parameters: "\
                "%s" % ",".join(multiple_args)

# We can't actually tell which case it is, 
        # so I'm raising a 404 because that covers 2/3 of the
        # possibilities
        # 
        # In the case where the method does not allow body
        # arguments it's definitely a 404.
        message = None
        if show_mismatched_params:
            message="Missing parameters: %s" % ",".join(missing_args)
        raise cherrypy.HTTPError(404, message=message)

    # the extra positional arguments come from the path - 404 Not Found
    if not varargs and vararg_usage > 0:
        raise cherrypy.HTTPError(404)

    body_params = cherrypy.serving.request.body.params or {}
    body_params = set(body_params.keys())
    qs_params = set(callable_kwargs.keys()) - body_params

    if multiple_args:
        if qs_params.intersection(set(multiple_args)):
            # If any of the multiple parameters came from the query string then
            # it's a 404 Not Found
            error = 404
        else:
            # Otherwise it's a 400 Bad Request
            error = 400

        message = None
        if show_mismatched_params:
            message="Multiple values for parameters: "\
                    "%s" % ",".join(multiple_args)

def script_name(self, path=None):
        """The script_name of the app at the given path, or None.

        If path is None, cherrypy.request is used.
        """
        if path is None:
            try:
                request = cherrypy.serving.request
                path = httputil.urljoin(request.script_name,
                                        request.path_info)
            except AttributeError:
                return None

        while True:
            if path in self.apps:
                return path

            if path == "":
                return None

            # Move one node up the tree and try again.
            path = path[:path.rfind("/")]

def script_name(self, path=None):
        """Return the script_name of the app at the given path, or None.

        If path is None, cherrypy.request is used.
        """
        if path is None:
            try:
                request = cherrypy.serving.request
                path = httputil.urljoin(request.script_name,
                                        request.path_info)
            except AttributeError:
                return None

        while True:
            if path in self.apps:
                return path

            if path == '':
                return None

            # Move one node up the tree and try again.
            path = path[:path.rfind('/')]

def _setup(self):
        """Hook this tool into cherrypy.request.

        The standard CherryPy request object will automatically call this
        method when the tool is "turned on" in config.
        """
        conf = self._merged_args()
        p = conf.pop('priority', None)
        if p is None:
            p = getattr(self.callable, 'priority', self._priority)
        cherrypy.serving.request.hooks.attach(self._point, self.callable,
                                              priority=p, **conf)