Multihooks

Multihooks is a software design approach that enables multiple handlers to be registered for a single extension point or event, allowing a broad set of behaviors to be composed without modifying core code. In a multihook system, a central registry maps hook points to lists of callbacks. Clients register handlers with optional metadata such as priority or stage. When the hook point fires, the system executes the registered handlers in a defined order, either synchronously or asynchronously. Some implementations support short-circuiting, shared return values, or error handling policies that determine whether subsequent handlers run.

Variants and scope vary by project. Multihooks can be global, component-scoped, or organized into hierarchical pipelines. Execution order may be determined by explicit priority, registration order, or a combination. Isolation and fault tolerance are common concerns, with options for run-to-completion, parallel execution, or error boundaries that prevent a failing handler from breaking the entire chain.

Usage scenarios include plugin architectures, content management systems, build tools, and frameworks that require extensibility without core changes. Multihooks reduce coupling and enable feature evolution, but they can introduce complexity, interoperability issues, and performance overhead if not carefully managed. Clear contracts for handler behavior, timing, timeouts, and error handling are important to maintain reliability and debuggability.

Relation to other patterns: multihooks are related to event-driven design, the observer pattern, middleware, and event buses, but emphasize multiple handlers per hook point and structured execution order. History of the term is informal, with implementations varying across ecosystems. See also hooks, event bus, plugin architecture, middleware, observer pattern.