Overview

We developed LINE Bot to learn Web API. This time we will create an echoBot that returns a simple sent text as it is. Develop with Rails and even deploy to Heroku.

environment

・ Ruby 2.6.5 ・ Rails 6.0.3.2 ・ PostgreSQL ・ Heroku

・ Create a channel with LINE Developers -Create a program for the bot itself (Ruby / Rails) -Deploy to Heroku

Create a channel with LINE Developers

First, register as a LINE developer. Then create a provider and channel to get the API key you need. https://developers.line.biz/ja/docs/messaging-api/getting-started/

Create a channel for Bot by referring to the formula (above). If you itemize the work easily,

-Log in to the LINE Developers console -Create a developer account by entering your name and email address ・ Create provider and channel, specify Messaging API at this time ・ Issue an access token ・ Turn off response messages and turn on Webhock

A Channel secret and a Channel access token are required for bot development, so make a note here!

Create a program for the bot itself (Ruby / Rails)

The DB uses PostgreSQL because it will be deployed on Heroku.

$rails new app name-d postgresql
$cd app name
$ git init

Install the required gems

Use a gem called line-bot-api.

`Gemfile`


gem 'line-bot-api'

$ bundule install

Implementation

1. Routing settings

`config/routes.rb`



Rails.application.routes.draw do  
    post '/callback' => 'linebot#callback'  
end

2. Create a controller

$ rails g controller linebot

3. Description to the controller

The description to the controller was (copied) with reference to RUBY of the official line SDK. https://github.com/line/line-bot-sdk-ruby/blob/master/examples/echobot/app.rb

`python`


class LinebotController < ApplicationController
 require 'line/bot'  # gem 'line-bot-api'

def client
  @client ||= Line::Bot::Client.new { |config|
    config.channel_secret = ENV["LINE_CHANNEL_SECRET"]
    config.channel_token = ENV["LINE_CHANNEL_TOKEN"]
  }
end

post '/callback' do
  body = request.body.read

  signature = request.env['HTTP_X_LINE_SIGNATURE']
  unless client.validate_signature(body, signature)
    halt 400, {'Content-Type' => 'text/plain'}, 'Bad Request'
  end

  events = client.parse_events_from(body)

  events.each do |event|
    case event
    when Line::Bot::Event::Message
      case event.type
      when Line::Bot::Event::MessageType::Text
        message = {
          type: 'text',
          text: event.message['text']
        }
        client.reply_message(event['replyToken'], message)
      end
    end
  end

  "OK"
 end
end

Deploy to Heroku

First, log in to Heroku, create an app on Heroku, and deploy it.

Set environment variables on Heroku side.

$ heroku config:set LINE_CHANNEL_SECRET=Paste the Channel Secret you noted earlier here
$ heroku config:set LINE_CHANNEL_TOKEN=Paste the access token you noted earlier here

Set Webhook settings with LINE developers

Set the URL with / callback at the end of the deployed address in the webhook.

This completes the echo-bot. Sending the text will return the same text.

Summary

Currently, after changing the code, it will not be reflected unless it is deployed, so Next time, I will use ngrok to run it in a local environment. https://qiita.com/shizu9d/items/42b2cb209b2e23a9af6d

References

I referred to the following article. https://qiita.com/noriya1217/items/00d6461e9f54900377a3

[Rails] Create an echo bot using the LINE Messaging API.