Create Extension

Write an extension

If you create a extension that might be useful for other people, make sure to open a issue about it.

import cheetah, { createExtension } from 'https://deno.land/x/cheetah/mod.ts'

export const ext = createExtension<{
  // The settings for your extension:
  foo: string
}>({
  onRequest({ _, app, req }) {
    ...
  }
})

Alternatively, you can create one without settings:

import cheetah, { createExtension } from 'https://deno.land/x/cheetah/mod.ts'

export const ext = createExtension({
  onRequest({ _, app, req }) { // access context to modify request/response
    ...
  }
})

Events

onPlugIn

This listener gets only executed on the first incoming request (in order to include environment variables on Cloudflare Workers).

onRequest

This listener gets executed before any routing to allow for full flexibility.

The data consists of:

• _ - The settings object you've specified. If all fields in your settings object are optional, it might be undefined.
• app - The app context including information such as a set of all routes, the IP address of the incoming request, the runtime, environment variables (if runtime is Cloudflare), the querystring & pathname and the proxy.
• req - The Request object.

onResponse

This listener gets executed just before a response is constructed.

The data consists of:

• _ - The settings object you've specified. If all fields in your settings object are optional, it might be undefined.
• app - The app context including information such as a set of all routes, the IP address of the incoming request, the runtime, environment variables (if runtime is Cloudflare), the querystring & pathname and the proxy.
• c - The context (including request, response and other already known features).