api.service.RoutesPerPrefix

This service implements a class involved in Hitchy's attempt to optimize routing definitions for dispatching incoming requests at runtime. Creating and managing instances of this class is tightly integrated with RoutesPerMethod which is another class used to optimize routing definitions.

Glossary

A route's prefix is the leading part of the path name pattern in its source that does not contain any parameters. Prefixes are used to reduce the number of lookups necessary to find authoritative request handlers on dispatching an incoming request.

Constructor

Instances can be constructed without any argument. Such an instance is capable of collecting any route. If a collected route's prefix has not been seen before, a new list for that prefix is set up automatically. Such an instance is considered extensible and its extensible properly is true accordingly.

const byPrefix = new api.service.RoutesPerPrefix();

However, instances are usually constructed by method optimizeByPrefix() of RoutesPerMethod. That method is replacing a flat list of collected routes associated with a particular HTTP method with an instance of this class meant to maintain the same set of routes in a different way. It starts with extracting all prefixes found in those routes and provides them as a list of strings in first argument when constructing the instance. This results in a non-extensible instance which is collecting routes matching one of those prefixes, only.

const byPrefix = new api.service.RoutesPerPrefix( prefixes );

Properties

extensible

This boolean property indicates whether routes with arbitrary prefixes can be collected or not. It depends on the way the instance has been constructed.

prefixes

This property exposes a list of routes for every prefix seen in a collected route.

Methods

append()

This method accepts a single route in first argument to be collected. Using the route's selectProbablyCoveredPrefixes() method, the route may be collected in one or more lists each related to a particular prefix.

byPrefix.append( someRoute );

The method returns current instance of RoutesPerPrefix for daisy-chaining calls.

dump()

This method is returning a string describing all currently maintained lists of routes per prefix in a human-readable way for debugging purposes.

console.log( byPrefix.dump() );

getLongestMatchingPrefix()

The method accepts the prefix of an incoming request as argument. It checks all prefixes currently associated with a list of routes internally to find the prefix sharing the longest leading part with the provided one. That prefix is returned eventually.

This method is used on dispatching an incoming request to pick the list of routes matching best the request's path. The according list is fetched with onPrefix() afterward.

onPrefix()

The method retrieves a list of routes sharing a prefix similar to the one provided as sole argument.

const routes = byPrefix.onPrefix( "/api/" );