Hooks

Server hooks to handle Pre and Post requests

Overview

Hooks allows us to handle request based on the request method and URI pattern.

Types

There are two types of hooks - Before and After, each type will apply first or last in order based on the type.

BeforeHook

The before hook will apply first, before any middleware will take place

AfterHook

The after hook will apply last, after the request ends and response returned to the client.

Usage

Basic usage

The Before and After hooks use as decorator for method

@BeforeHook(pattern: string, method?: HTTP_METHOD, options?: IHookOptions)
beforeHookFn(req, res, next) {
// method to be apply before the endpoint trigger
}
@AfterHook(pattern: string, method?: HTTP_METHOD, options?: IHookOptions)
afterHookFn(req, res, next) {
// method to be apply after the endpoint trigger
}

Hook should be end by calling to the next method

Example

export class Hooks{
static counter: number = 0
private logger: Logger;
@BeforeHook('*')
beforeAll(req, res, next) {
res.counter = ++Hooks.counter
next()
}
@AfterHook('/*/:id', HTTP_METHOD.GET)
afterRead(req, res, next) {
const payload = Object.assign({reqCounter: req['counter']}, req.params)
this.logger.log('read was apply', payload)
next()
}
}

Priority

We can control the order of hooks apply be setting the hook priority.

Lower the number is, hook priority is higher and will apply earlier

Example

export class Hooks{
static counter: number = 0
private logger: Logger;
@BeforeHook('*', HTTP_METHOD.ALL, {priority: 0}) // apply first
beforeAll(req, res, next) {
res.counter = ++Hooks.counter
next()
}
@BeforeHook('/*/:id', HTTP_METHOD.GET, {priority: 1})// apply second
beforeRead(req, res, next) {
const payload = Object.assign({reqCounter: req['counter']}, req.params)
this.logger.log('read was apply', payload)
next()
}
}