zhin-context-services

name	zhin-context-services
description	Details Zhin context services (config, database, cron, permission) and how to register or consume them in plugins.
license	MIT
metadata	{"author":"zhinjs","version":"1.0","framework":"zhin"}

Zhin Context & Services Skill

Use this skill when developers need to interact with built-in contexts or provide custom services via defineContext.

Accessing Built-in Services

import { usePlugin } from '@zhin.js/core'

const plugin = usePlugin()

// Inject built-in contexts
const config = plugin.inject('config')
const permissions = plugin.inject('permission')
const cronService = plugin.inject('cron')

Use plugin.contextIsReady('service') to check if a context is available before using it.

Config Service

Load or read config files via ConfigService:

const configService = plugin.inject('config')
const config = configService?.get('zhin.config.yaml', {
  debug: false,
  plugins: []
})

Notes:

• Supported formats: .json, .yaml, .yml
• Config values can reference environment variables using ${ENV_NAME:default}

Cron Service

Register scheduled tasks using the Cron class and addCron:

import { Cron } from '@zhin.js/core'

plugin.addCron(new Cron('0 * * * *', async () => {
  plugin.logger.info('Hourly task')
}))

Cron entries are auto-started and stopped when the plugin is disposed.

Permission Service

The permission service provides checks in MessageCommand.permit(...). You can also extend it by pushing a new check function:

const permission = plugin.inject('permission')
permission?.add({
  name: /^role\(.+\)$/,
  check: async (name, message) => {
    // custom role validation
    return false
  }
})

Database Service

If the database context is enabled, use it via plugin.inject('database'):

const database = plugin.inject('database')
const users = await database?.select('User')

To define new models, call plugin.defineModel(name, definition) if the database service is active.

Defining Custom Contexts

import { defineContext, usePlugin } from '@zhin.js/core'

const plugin = usePlugin()

plugin.provide(defineContext({
  name: 'metrics',
  description: 'Metrics service',
  mounted: async () => ({
    counter: 0
  }),
  dispose: (value) => {
    // cleanup
  },
  extensions: {
    increment() {
      this.counter += 1
    }
  }
}))

Custom contexts can also extend Plugin.Extensions so you can call new helper methods from plugins.