Source code for watson.framework.controllers

# -*- coding: utf-8 -*-
import abc
import collections
import re
from watson.di import ContainerAware
from watson.events import types
from watson.framework import events
from watson.http.messages import Response, Request
from watson.common.imports import get_qualified_name
from watson.common.contextmanagers import suppress


ACCEPTABLE_RETURN_TYPES = (str, int, float, bool)


[docs]class Base(ContainerAware, metaclass=abc.ABCMeta): """The base class for all controllers. Attributes: __action__ (string): The last action that was called on the controller. """ def execute(self, **kwargs): method = self.get_execute_method(**kwargs) self.__action__ = method return method(**kwargs) or {} @abc.abstractmethod def get_execute_method(self, **kwargs): raise NotImplementedError( 'You must implement get_execute_method') # pragma: no cover @abc.abstractmethod def get_execute_method_path(self, **kwargs): raise NotImplementedError( 'You must implement get_execute_method_path') # pragma: no cover def __repr__(self): return '<{0}>'.format(get_qualified_name(self))
[docs]class HttpMixin(object): """A mixin for controllers that can contain http request and response objects. Attributes: _request: The request made that has triggered the controller _response: The response that will be returned by the controller """ _event = None @property def event(self): """The event that was triggered that caused the execution of the controller. Returns: watson.events.types.Event """ if not self._event: self._event = types.Event( events.DISPATCH_EXECUTE, params={'context': {}}) return self._event @event.setter def event(self, event): """Set the request object. Args: event (watson.events.types.Event): The triggered event. Raises: TypeError if the event type is not a subclass of watson.events.types.Event """ if not isinstance(event, types.Event): raise TypeError( 'Invalid request type, expected watson.events.types.Event') self._event = event @property def request(self): """The HTTP request relating to the controller. Returns: watson.http.messages.Request """ if 'request' not in self.event.params['context']: return None return self.event.params['context']['request'] @request.setter def request(self, request): """Set the request object. Args: request (watson.http.messages.Request): The request associated with the controller. Raises: TypeError if the request type is not of watson.http.messages.Request """ if not isinstance(request, Request): raise TypeError( 'Invalid request type, expected watson.http.messages.Request') self.event.params['context']['request'] = request @property def response(self): """The HTTP response related to the controller. If no response object has been set, then a new one will be generated. Returns: watson.http.messages.Response """ if 'response' not in self.event.params['context']: self.response = Response() return self.event.params['context']['response'] @response.setter def response(self, response): """Set the request object. Args: response (watson.http.messages.Response): The response associated with the controller. Raises: TypeError if the request type is not of watson.http.messages.Response """ if not isinstance(response, Response): raise TypeError( 'Invalid response type, expected watson.http.messages.Response') self.event.params['context']['response'] = response
[docs] def url(self, route_name, host=None, scheme=None, **params): """Converts a route into a url. Args: route_name (string): The name of the route to convert host (string): The hostname to prepend to the route path scheme (string): The scheme to prepend to the route path params (dict): The params to use on the route Returns: The assembled url. """ if not params: params = {} router = self.container.get('router') path = router.assemble(route_name, **params) if host: path = '{0}{1}'.format(host, path) if scheme: path = '{0}{1}'.format(scheme, path) return path
[docs] def redirect(self, path, params=None, status_code=302, clear=False): """Redirect to a different route. Redirecting will bypass the rendering of the view, and the body of the request will be displayed. Also supports Post Redirect Get (http://en.wikipedia.org/wiki/Post/Redirect/Get) which can allow post variables to accessed from a GET resource after a redirect (to repopulate form fields for example). Args: path (string): The URL or route name to redirect to params (dict): The params to send to the route status_code (int): The status code to use for the redirect clear (bool): Whether or not the session data should be cleared Returns: A watson.http.messages.Response object. """ self.response.status_code = status_code if self.request.is_method('POST', 'PUT'): self.response.status_code = status_code if status_code != 302 else 303 self.request.session['post_redirect_get'] = dict(self.request.post) if clear: self.clear_redirect_vars() try: url = self.url(path, **params or {}) except KeyError: url = path self.response.headers.add('location', url, replace=True) return self.response
@property def redirect_vars(self): """Returns the post variables from a redirected request. """ return self.request.session.get('post_redirect_get', {})
[docs] def clear_redirect_vars(self): """Clears the redirected variables. """ del self.request.session['post_redirect_get']
[docs] def forward(self, controller, method=None, *args, **kwargs): """Fowards a request across to a different controller. Attributes: controller (string|object): The controller to execute method (string): The method to run, defaults to currently called method Returns: Response from other controller. """ if not method: method = self.__action__ if not hasattr(controller, method): controller = self.container.get(controller) controller.request = self.request controller.event = self.event return getattr(controller, method)(*args, **kwargs)
@property def flash_messages(self): """Retrieves all the flash messages associated with the controller. Example: .. code-block:: python # within controller action self.flash_messages.add('Some message') return { 'flash_messages': self.flash_messages } # within view {% for namespace, message in flash_messages %} {{ message }} {% endfor %} Returns: A watson.framework.controllers.FlashMessagesContainer object. """ if not self.request.session: raise Exception('You must enable sessions in the application configuration.') if 'flash_messages' not in self.event.params['context']: self.event.params['context']['flash_messages'] = FlashMessagesContainer( self.request.session) return self.event.params['context']['flash_messages']
[docs]class FlashMessagesContainer(object): """Contains all the flash messages associated with a controller. Flash messages persist across requests until they are displayed to the user. """ messages = None session = None session_key = 'flash_messages'
[docs] def __init__(self, session): """Initializes the container. Args: session (watson.http.session.StorageMixin): A session object containing the flash messages data. """ self.session = session if self.session_key in self.session: self.messages = self.session[self.session_key] else: self.clear()
[docs] def add(self, message, namespace='info', write_to_session=True): """Adds a flash message within the specified namespace. Args: message (string): The message to add to the container. namespace (string): The namespace to sit the message in. """ self.messages.setdefault(namespace, []).append(message) if write_to_session: # ensure that the flash messages are written to the session self.__write_to_session()
[docs] def add_messages(self, messages, namespace='info'): """Adds a list of messages to the specified namespace. Args: messages (list|tuple): The messages to add to the container. namespace (string): The namespace to sit the messages in. """ for message in messages: self.add(message, namespace, write_to_session=False) self.__write_to_session()
[docs] def clear(self): """Clears the flash messages from the container and session. This is called automatically after the flash messages have been iterated over. """ with suppress(KeyError): del self.session[self.session_key] self.messages = collections.OrderedDict() self.__write_to_session()
def __write_to_session(self): self.session[self.session_key] = self.messages # Internals def __iter__(self): for namespace, messages in self.messages.items(): for message in messages: yield (namespace, message) else: self.clear() def __getitem__(self, key): return self.messages.get(key) def __len__(self): return len(self.messages) def __repr__(self): return '<{0} namespaces:{1}>'.format(get_qualified_name(self), len(self))
[docs]class Action(Base, HttpMixin): """A controller thats methods can be accessed with an _action suffix. Example: .. code-block:: python class MyController(controllers.Action): def my_func_action(self): return 'something' """ def execute(self, **kwargs): actual_kwargs = kwargs.copy() with suppress(Exception): del actual_kwargs['action'] method = self.get_execute_method(**kwargs) return method(**actual_kwargs) or {} def get_action(self, **kwargs): action = kwargs.get('action') if not action: action = 'index' return action def get_execute_method(self, **kwargs): method_name = self.get_action(**kwargs) + '_action' self.__action__ = method_name return getattr(self, method_name) def get_execute_method_path(self, **kwargs): template = re.sub('.-', '_', self.get_action(**kwargs).lower()) return [self.__class__.__name__.lower(), template]
[docs]class Rest(Base, HttpMixin): """A controller thats methods can be accessed by the request method name. Example: .. code-block:: python class MyController(controllers.Rest): def GET(self): return 'something' """ def get_execute_method(self, **kwargs): return getattr(self, self.request.method) def get_execute_method_path(self, **kwargs): template = self.request.method.lower() return [self.__class__.__name__.lower(), template]