import types import sys from inspect import getmembers import six from webob.exc import HTTPFound from .util import iscontroller, _cfg __all__ = [ 'PecanHook', 'TransactionHook', 'HookController', 'RequestViewerHook' ] def walk_controller(root_class, controller, hooks, seen=None): seen = seen or set() if type(controller) not in vars(six.moves.builtins).values(): # Avoid recursion loops try: if controller in seen: return seen.add(controller) except TypeError: # If we discover an unhashable item (like a list), it's not # something that we want to traverse because it's not the sort of # thing we would add a hook to return for hook in getattr(controller, '__hooks__', []): # Append hooks from controller class definition hooks.add(hook) for name, value in getmembers(controller): if name == 'controller': continue if name.startswith('__') and name.endswith('__'): continue if iscontroller(value): for hook in hooks: value._pecan.setdefault('hooks', set()).add(hook) elif hasattr(value, '__class__'): # Skip non-exposed methods that are defined in parent classes; # they're internal implementation details of that class, and # not actual routable controllers, so we shouldn't bother # assigning hooks to them. if ( isinstance(value, types.MethodType) and any(filter(lambda c: value.__func__ in c.__dict__.values(), value.im_class.mro()[1:])) ): continue walk_controller(root_class, value, hooks, seen) class HookControllerMeta(type): ''' A base class for controllers that would like to specify hooks on their controller methods. Simply create a list of hook objects called ``__hooks__`` as a member of the controller's namespace. ''' def __init__(cls, name, bases, dict_): hooks = set(dict_.get('__hooks__', [])) for base in bases: # Add hooks from parent class and mixins for hook in getattr(base, '__hooks__', []): hooks.add(hook) walk_controller(cls, cls, hooks) HookController = HookControllerMeta( 'HookController', (object,), {'__doc__': ("A base class for controllers that would like to specify " "hooks on their controller methods. Simply create a list " "of hook objects called ``__hooks__`` as a class attribute " "of your controller.")} ) class PecanHook(object): ''' A base class for Pecan hooks. Inherit from this class to create your own hooks. Set a priority on a hook by setting the ``priority`` attribute for the hook, which defaults to 100. ''' priority = 100 def on_route(self, state): ''' Override this method to create a hook that gets called upon the start of routing. :param state: The Pecan ``state`` object for the current request. ''' return def before(self, state): ''' Override this method to create a hook that gets called after routing, but before the request gets passed to your controller. :param state: The Pecan ``state`` object for the current request. ''' return def after(self, state): ''' Override this method to create a hook that gets called after the request has been handled by the controller. :param state: The Pecan ``state`` object for the current request. ''' return def on_error(self, state, e): ''' Override this method to create a hook that gets called upon an exception being raised in your controller. :param state: The Pecan ``state`` object for the current request. :param e: The ``Exception`` object that was raised. ''' return class TransactionHook(PecanHook): ''' :param start: A callable that will bind to a writable database and start a transaction. :param start_ro: A callable that will bind to a readable database. :param commit: A callable that will commit the active transaction. :param rollback: A callable that will roll back the active transaction. :param clear: A callable that will clear your current context. A basic framework hook for supporting wrapping requests in transactions. By default, it will wrap all but ``GET`` and ``HEAD`` requests in a transaction. Override the ``is_transactional`` method to define your own rules for what requests should be transactional. ''' def __init__(self, start, start_ro, commit, rollback, clear): self.start = start self.start_ro = start_ro self.commit = commit self.rollback = rollback self.clear = clear def is_transactional(self, state): ''' Decide if a request should be wrapped in a transaction, based upon the state of the request. By default, wraps all but ``GET`` and ``HEAD`` requests in a transaction, along with respecting the ``transactional`` decorator from :mod:pecan.decorators. :param state: The Pecan state object for the current request. ''' controller = getattr(state, 'controller', None) if controller: force_transactional = _cfg(controller).get('transactional', False) else: force_transactional = False if state.request.method not in ('GET', 'HEAD') or force_transactional: return True return False def on_route(self, state): state.request.error = False if self.is_transactional(state): state.request.transactional = True self.start() else: state.request.transactional = False self.start_ro() def before(self, state): if self.is_transactional(state) \ and not getattr(state.request, 'transactional', False): self.clear() state.request.transactional = True self.start() def on_error(self, state, e): # # If we should ignore redirects, # (e.g., shouldn't consider them rollback-worthy) # don't set `state.request.error = True`. # trans_ignore_redirects = ( state.request.method not in ('GET', 'HEAD') ) if state.controller is not None: trans_ignore_redirects = ( _cfg(state.controller).get( 'transactional_ignore_redirects', trans_ignore_redirects ) ) if type(e) is HTTPFound and trans_ignore_redirects is True: return state.request.error = True def after(self, state): if getattr(state.request, 'transactional', False): action_name = None if state.request.error: action_name = 'after_rollback' self.rollback() else: action_name = 'after_commit' self.commit() # # If a controller was routed to, find any # after_* actions it may have registered, and perform # them. # if action_name: controller = getattr(state, 'controller', None) if controller is not None: actions = _cfg(controller).get(action_name, []) for action in actions: action() self.clear() class RequestViewerHook(PecanHook): ''' :param config: A (optional) dictionary that can hold ``items`` and/or ``blacklist`` keys. :param writer: The stream writer to use. Can redirect output to other streams as long as the passed in stream has a ``write`` callable method. :param terminal: Outputs to the chosen stream writer (usually the terminal) :param headers: Sets values to the X-HTTP headers Returns some information about what is going on in a single request. It accepts specific items to report on but uses a default list of items when none are passed in. Based on the requested ``url``, items can also be blacklisted. Configuration is flexible, can be passed in (or not) and can contain some or all the keys supported. **items** This key holds the items that this hook will display. When this key is passed only the items in the list will be used. Valid items are *any* item that the ``request`` object holds, by default it uses the following: * path * status * method * controller * params * hooks .. note:: This key should always use a ``list`` of items to use. **blacklist** This key holds items that will be blacklisted based on ``url``. If there is a need to omit urls that start with `/javascript`, then this key would look like:: 'blacklist': ['/javascript'] As many blacklisting items as needed can be contained in the list. The hook will verify that the url is not starting with items in this list to display results, otherwise it will get omitted. .. note:: This key should always use a ``list`` of items to use. For more detailed documentation about this hook, please see :ref:`requestviewerhook` ''' available = ['path', 'status', 'method', 'controller', 'params', 'hooks'] def __init__(self, config=None, writer=sys.stdout, terminal=True, headers=True): if not config: self.config = {'items': self.available} else: if config.__class__.__name__ == 'Config': self.config = config.to_dict() else: self.config = config self.writer = writer self.items = self.config.get('items', self.available) self.blacklist = self.config.get('blacklist', []) self.terminal = terminal self.headers = headers def after(self, state): # Default and/or custom response information responses = { 'controller': lambda self, state: self.get_controller(state), 'method': lambda self, state: state.request.method, 'path': lambda self, state: state.request.path, 'params': lambda self, state: [ (p[0].encode('utf-8'), p[1].encode('utf-8')) for p in state.request.params.items() ], 'status': lambda self, state: state.response.status, 'hooks': lambda self, state: self.format_hooks(state.app.hooks), } is_available = [ i for i in self.items if i in self.available or hasattr(state.request, i) ] terminal = [] headers = [] will_skip = [ i for i in self.blacklist if state.request.path.startswith(i) ] if will_skip: return for request_info in is_available: try: value = responses.get(request_info) if not value: value = getattr(state.request, request_info) else: value = value(self, state) except Exception as e: value = e terminal.append('%-12s - %s\n' % (request_info, value)) headers.append((request_info, value)) if self.terminal: self.writer.write(''.join(terminal)) self.writer.write('\n\n') if self.headers: for h in headers: key = str(h[0]) value = str(h[1]) name = 'X-Pecan-%s' % key state.response.headers[name] = value def get_controller(self, state): ''' Retrieves the actual controller name from the application Specific to Pecan (not available in the request object) ''' path = state.request.pecan['routing_path'].split('/')[1:] return state.controller.__str__().split()[2] def format_hooks(self, hooks): ''' Tries to format the hook objects to be more readable Specific to Pecan (not available in the request object) ''' str_hooks = [str(i).split()[0].strip('<') for i in hooks] return [i.split('.')[-1] for i in str_hooks if '.' in i]