AWS DynamoDB session middleware for Telegraf

AWS DynamoDB powered session middleware for Telegraf.

Prerequisites

1. You have made your AWS access and secret key available through a provided method, like storing them in the ~/.aws/credentials file or export them into environment variables
2. You need to install Node.js with a minimum version of 6.10.3

Installation

foo@bar:~$ yarn add telegraf-session-dynamodb

Example

const Telegraf = require('telegraf')
const DynamoDBSession = require('telegraf-session-dynamodb')

const bot = new Telegraf(process.env.BOT_TOKEN)

const dynamoDBSession = new DynamoDBSession({
    dynamoDBConfig: {
        params: {
            TableName: process.env.AWS_DYNAMODB_TABLE
        },
        region: process.env.AWS_REGION
    }
})
bot.use(dynamoDBSession.middleware())

bot.on('text', (ctx) => {
  ctx.session.counter = ctx.session.counter || 0
  ctx.session.counter++
  console.log('Session', ctx.session)
})

bot.startPolling()

When you have stored the session key beforehand, you can access a session without having access to a context object. This is useful when you perform OAUTH or something similar, when a REDIRECT_URI is called on your bot server.

const dynamoDBSession = new DynamoDBSession({
    dynamoDBConfig: {
        params: {
            TableName: process.env.AWS_DYNAMODB_TABLE
        },
        region: process.env.AWS_REGION
    }
})

// Retrieve session state by session key
dynamoDBSession.getSession(key)
  .then((session) => {
    console.log('Session state', session)
  })

// Save session state
dynamoDBSession.saveSession(key, session)

API

Options

• dynamoDBConfig:
  • params:
    • TableName: AWS DynamoDB Table to store session (default: telegraf-session-dynamodb)
  • region: AWS Region (default: ap-northeast-1)
• property: context property name (default: session)
• ttl: Time To Live in minutes, -1 for never expire (default: -1)
• getSessionKey: session key resolver function (ctx) => any)

Default implementation of getSessionKey:

function getSessionKey(ctx) {
  if (!ctx.from || !ctx.chat) {
    return
  }
  return `${ctx.from.id}:${ctx.chat.id}`
}

Destroying a session

To destroy a session simply set it to null.

bot.on('text', (ctx) => {
  ctx.session = null
})

Local Unit Testing

foo@bar:~$ yarn

foo@bar:~$ yarn global add serverless

foo@bar:~$ docker pull lambci/lambda

foo@bar:~$ sls dynamodb install

foo@bar:~$ sls offline start -r ap-northeast-1 --noTimeout &

foo@bar:~$ yarn test:local

Remarks: TTL will NOT work for DynamoDB Local

Remote Unit Testing

1. Create the AWS DynamoDB Table in the desired AWS Region
2. Use SessionKey (String) as primary key
3. Set ttl as the TTL attribute in Manage TTL

foo@bar:~$ aws configure

foo@bar:~$ yarn

foo@bar:~$ yarn test

Acknowledgement

• telegraf-session-redis