using-plug-ins.md

Using-Plug-ins

• Using Plug-ins
  • Execution Order
  • Writing a Plug-in
• Next Up...

Using Plug-ins

Angel is designed to be extensible. As such, it exposes a typedef, AngelConfigurer, that has special privileges within the framework - they act as plug-ins and can be called via app.configure().

Plug-ins simply need to accept an Angel instance as a parameter, and return a Future (the result of which will be ignored, unless it throws an error). Angel instances have several facilities available to be customized, and thus it is easy to use a custom plug-in to bring about desired functionality within your application.

typedef Future AngelConfigurer(Angel app);

As a convention, Angel plug-ins should be hooked up before the call to startServer.

import 'dart:io';
import 'package:angel_framework/angel_framework';

plugin(Angel app) async {
  print("Do stuff here");
}

main() async {
  Angel app = new Angel();
  await app.configure(plugin);
  await app.startServer();
}

Execution Order

Plugins are usually immediately invoked by app.configure(). However, you may run into certain plug-ins that depend on other facilities already being available, or all of your services already being mounted. You can set aside a plug-in to be run just before server startupby adding it to app.startupHooks, instead of directly calling app.configure().

app.startupHooks.addAll([
  myPlugin(),
  AngelWebSocket().configureServer,
  fooBarBazQuux()
]);

Likewise, you can add hooks that run just before the app is shutdown, via Angel.shutdownHooks.

Next Up...

Learn how to generate content for clients by rendering views.