Perhandler

Perhandler is a term used in software architecture to describe a lifecycle policy in which a new instance of a request handler is created for each incoming request and disposed when the request completes. The concept emphasizes isolation of per-request state from other requests and from long-lived application state. The term appears in web frameworks, services architectures, and dependency injection systems that distinguish handler-scoped lifetimes from singleton or application-wide lifetimes. In practice, a per-handler model means that each request is processed by its own handler object, which may hold temporary data, resources, or context relevant only to that request.

Benefits of the per-handler approach include improved thread safety by avoiding shared mutable state across requests, and easier cleanup of resources. It is useful when handlers read from or write to per-request data or when resources such as database connections should be opened and closed per request. This model helps ensure that the lifecycle of such resources aligns with the request processing window.

Implementation is typically achieved via dependency injection containers or frameworks that instantiate a fresh handler per request and dispose of it at the end of processing. Developers should manage cross-request resources carefully to avoid performance costs from repeated allocations and ensure that long-lived resources are not stored in a per-handler instance. Awareness of cross-cutting concerns, which may require middleware or ambient context, is important for maintaining consistency across requests.

Per-handler lifetimes are closely related to per-request or handler-scoped lifetimes and are often used interchangeably in some ecosystems. They differ from singleton lifetimes that share state across requests. See also: per-request lifetime, dependency injection scope, handler, middleware.