A hook refers to replacing or extending a system or application's default behavior with a custom behavior for a specific event. For keyboard hooks prefer the tag [keyhook]. For git related hooking use the tag [githooks] alone. For hooking web services use the tag [webhooks] instead. For React hooks use tag[react-hooks].
What is it?
A hook refers to replacing or extending the default behavior with a custom behavior for specific events. The events may be operating system events, but also application events that are meant to be extended with hooks.
The hook may fully replace the default behavior. It may also just extend the default behavior for example by adding a listening or monitoring activity without changing the default behavior, or add an extra effect on the top of it.
Hooking and programming techniques
"Hook" is commonly used to describe replacing a function pointer in an existing data structure with a new function pointer that points to new code. This new code can extend the default behavior by calling the old function pointer before or after the new code executes, or the new code can replace / disable the existing behavior by not calling the old pointer.
Hooking is similar in concept to OOP inheritance, but is usually more dynamic (determined at runtime) than OOP inheritance.
Essentially it's a place in code that allows you to tap in to a module to either provide different behavior or to react when something happens. Hooks often (but not always) use callback functions. For example, you might hook an event system using hookEvent(Events.STARTUP, myCallbackFunction). You are passing a function pointer to the hookEvent function, so it knows what function to call when the event occurs.
How does it work?
Typically hooks are inserted while software is already running, but hooking is a tactic that can also be employed prior to the application being started. There are two techniques to achieve this:
- Physical modification
- Runtime modification
Related tags and disambiguation
- For the hooks related to keyboard events, prefer the tag keyhook
- For the hooking git events, you must use the tag githooks preferably without the hooking
- For hooking web services with web service callbacks prefer the tag webhooks
- For React hooks, prefer the tag react-hooks
