Context Middleware

This middleware is designed to be used with node-telegram-bot-api-middleware.

For each incoming message this middleware adds a custom context object this.ctx that is shared between all handlers.

Useful for designing complex request processing logic involving custom handler interoperation.

Context can be used to create generic handler that:

• displays help information if there is no any specific handler for the request
• processes arbitrary user text input that is not meant for any specific handler to process. In this case it is best to also use state machines to fully control the bot's logic.

Intallation

npm i node-telegram-bot-api-middleware-context

Usage

const TelegramBot = require('node-telegram-bot-api')
const use = require('node-telegram-bot-api-middleware').use
const createContextMiddleware = require('node-telegram-bot-api-middleware-context')

const bot = new TelegramBot('YOUR_TELEGRAM_BOT_TOKEN', { polling: true })

let response = use(createContextMiddleware()) /* .use(otherMiddleware) */

/*
 * Handlers are called in the order of their creation:
 * 1. /start (specific handler)
 * 2. .+ (generic handler)
 */

bot.onText(
    new RegExp('/start'),
    response(function(msg, match) {
        this.ctx.messageHandled = true // set custom flag to indicate that the message was handled
        this.ctx.arbitraryProp = 'value' // add any property to the context

        bot.sendMessage(this.chatId, `Message '${msg.text}' was handled by a specific handler`)
    })
)

bot.onText(
    /.+/,
    response(function(msg, match) {
        if (this.ctx.messageHandled) {
            // do nothing if the message has already been handled
            return
        }

        // otherwise process the unhandled message using generic handler
        bot.sendMessage(this.chatId, `Message '${msg.text}' was handled by a generic handler`)
    })
)