t.p.hook : module documentation

Part of twisted.python View Source

I define support for hookable instance methods.

These are methods which you can register pre-call and post-call external functions to augment their functionality. People familiar with more esoteric languages may think of these as "method combinations".

This could be used to add optional preconditions, user-extensible callbacks (a-la emacs) or a thread-safety mechanism.

The four exported calls are:

All have the signature (class, methodName, callable), and the callable they take must always have the signature (instance, *args, **kw) unless the particular signature of the method they hook is known.

Hooks should typically not throw exceptions, however, no effort will be made by this module to prevent them from doing so. Pre-hooks will always be called, but post-hooks will only be called if the pre-hooks do not raise any exceptions (they will still be called if the main method raises an exception). The return values and exception status of the main method will be propogated (assuming none of the hooks raise an exception). Hooks will be executed in the order in which they are added.

Class HookError An error which will fire when an invariant is violated.
Function addPre hook.addPre(klass, name, func) -> None
Function addPost hook.addPost(klass, name, func) -> None
Function removePre hook.removePre(klass, name, func) -> None
Function removePost hook.removePre(klass, name, func) -> None
Function PRE (private) munging to turn a method name into a pre-hook-method-name
Function POST (private) munging to turn a method name into a post-hook-method-name
Function ORIG (private) munging to turn a method name into an `original' identifier
Function _XXX string manipulation garbage
Function _addHook (private) adds a hook to a method on a class
Function _removeHook (private) removes a hook from a method on a class
Function _enhook (private) causes a certain method name to be hooked on a class
Function _dehook (private) causes a certain method name no longer to be hooked on a class
def addPre(klass, name, func): (source)
hook.addPre(klass, name, func) -> None

Add a function to be called before the method klass.name is invoked.

def addPost(klass, name, func): (source)
hook.addPost(klass, name, func) -> None

Add a function to be called after the method klass.name is invoked.

def removePre(klass, name, func): (source)
hook.removePre(klass, name, func) -> None

Remove a function (previously registered with addPre) so that it is no longer executed before klass.name.

def removePost(klass, name, func): (source)
hook.removePre(klass, name, func) -> None

Remove a function (previously registered with addPost) so that it is no longer executed after klass.name.

def _XXX(k, n, s): (source)
string manipulation garbage
def PRE(k, n): (source)
(private) munging to turn a method name into a pre-hook-method-name
def POST(k, n): (source)
(private) munging to turn a method name into a post-hook-method-name
def ORIG(k, n): (source)
(private) munging to turn a method name into an `original' identifier
def _addHook(klass, name, phase, func): (source)
(private) adds a hook to a method on a class
def _removeHook(klass, name, phase, func): (source)
(private) removes a hook from a method on a class
def _enhook(klass, name): (source)
(private) causes a certain method name to be hooked on a class
def _dehook(klass, name): (source)
(private) causes a certain method name no longer to be hooked on a class
API Documentation for Twisted, generated by pydoctor at 2012-06-04 17:20:01.