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Module: hook | Twisted-0.19.0/twisted/python/hook.py
--- | ---
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: addPre addPost removePre removePost 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.
Imported modules |
--- | ---
import reflect import string
Functions |
ORIG POST PRE _XXX _addHook _dehook | _enhook _removeHook addPost addPre removePost removePre
| ORIG
    ORIG ( k,  n )
(private) munging to turn a method name into an `original' identifier
| POST
    POST ( k,  n )
(private) munging to turn a method name into a post-hook-method-name
| PRE
    PRE ( k,  n )
(private) munging to turn a method name into a pre-hook-method-name
| _XXX
    _XXX (
            k,
            n,
            s,
            )
string manipulation garbage
| _addHook
    _addHook (
            klass,
            name,
            phase,
            func,
            )
(private) adds a hook to a method on a class
| _dehook
    _dehook ( klass,  name )
(private) causes a certain method name no longer to be hooked on a class
Exceptions |
--- | ---
HookError( "Cannot unhook!" )
| _enhook
    _enhook ( klass,  name )
(private) causes a certain method name to be hooked on a class
| _removeHook
    _removeHook (
            klass,
            name,
            phase,
            func,
            )
(private) removes a hook from a method on a class
Exceptions |
--- | ---
HookError( "no hooks present!" ) HookError("hook %s not found in removal list for %s" %( name, klass ) )
| addPost
    addPost (
            klass,
            name,
            func,
            )
### hook.addPost(klass, name, func) -> None Add a function to be called before the method klass.name is invoked.
| addPre
    addPre (
            klass,
            name,
            func,
            )
### hook.addPre(klass, name, func) -> None Add a function to be called before the method klass.name is invoked.
| removePost
    removePost (
            klass,
            name,
            func,
            )
### hook.removePre(klass, name, func) -> None Remove a function (previously registered with addPost) so that it is no longer executed after klass.name.
| removePre
    removePre (
            klass,
            name,
            func,
            )
### hook.removePre(klass, name, func) -> None Remove a function (previously registered with addPre) so that it is no longer executed before klass.name.
Classes |
HookError | An error which will fire when an invariant is violated.

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