extension.py

A template of a WebCore 2 extension.

Only the init method is requried.

The class attributes listed below control ordering and activation of other extensions.

uses: : Used for extension sorting and dependency graphing; if these features are present we can use them. needs: : As per uses, but requires the named features be present. always: : If True always load this extension. Useful for application-provided extensions. never: : The opposite of always. first: : Always try to be first in the extension stack. last: : Always try to be last in the extension stack. provides: : A list of keywords usable in uses and needs declarations. extensions: : A tuple of entry_point namespaces to search for extensions.

The names of method arguments are unimportant; all values are passed positionally.

 
class Extension(object):
	
	uses = []
	needs = []
	always = False
	never = False
	first = False
	last = False
	provides = []
	extensions = ()

Executed to configure the extension.

No actions must be performed here, only configuration management.

You can also update the class attributes here. It only really makes sense to add dependencies.

 
	def __init__(self, **config):
		
		super(Extension, self).__init__()

Executed to wrap the application in middleware.

The first argument is the global context class, not request-local context instance.

Accepts a WSGI application as the second argument and must likewise return a WSGI app.

 
	def __call__(self, context, app):
		
		return app

Executed during application startup just after binding the server.

The first argument is the global context class, not request-local context instance.

Any of the actions you wanted to perform during __init__ you should do here.

 
	def start(self, context):
		
		pass

Executed during application shutdown after the last request has been served.

The first argument is the global context class, not request-local context instance.

 
	def stop(self, context):
		pass

Called when a SIGHUP is sent to the application.

The first argument is the global context class, not request-local context instance.

Allows your code to re-load configuration and your code should close then re-open sockets and files.

 
	def graceful(self, context, **config):
		pass

Executed during request set-up to populate the thread-local context instance.

The purpose of the extension ordering is to ensure that methods like these are executed in the correct order.

 
	def prepare(self, context):
		pass

Executed as dispatch descends into a tier.

The consumed argument is a Path object containing one or more path elements. The handler argument is the literal object that was selected to process the consumed elements. The is_endpoint argument is True if there will be no futher dispatch.

Generally called in series, like:

    # Index method example.
    dispatch(context, '', RootController, True)

    # Data-based example.
    dispatch(context, '', RootController, False)
    dispatch(context, 'admin', AdminController, False)
    dispatch(context, 'user', UsersController, False)
    dispatch(context, '27', UserController(27), False)
    dispatch(context, 'modify', UserController(27).modify, True)

    # Contentment example.
    dispatch(context, '', AssetController, False)
    dispatch(context, 'company/about/staff', PageController, False)
    dispatch(context, 'view:page', PageController.page, True)

    # Route example.
    dispatch(context, '/admin/user/27/modify', modify_user, True)

	def dispatch(self, context, consumed, handler, is_endpoint):
		
		pass

Executed after all extension prepare methods have been called, prior to dispatch.

 
	def before(self, context):
		pass

Executed after dispatch has returned and the response populated, prior to anything being sent to the client.

Similar to middleware, the first extension registered has its after method called last.

 
	def after(self, context):
		pass

Inspect and potentially mutate the given handler's arguments.

The args list and kw dictionary may be freely modified, though invalid arguments to the handler will fail.

 
	def mutate(self, context, handler, args, kw):
		pass

Transform outgoing values prior to view lookup.

 
	def transform(self, context, handler, result):
		pass

Populate an interactive shell.

 
	def interactive(self):
		return dict()

Return an object conforming to the inspector panel API.

 
	def inspect(self, context):
		
		pass