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# Building a sample bot with Heroku

Heroku's free plan has been discontinued

Heroku's free plan has been discontinued as of November 27, 2022. If you would like to try this tutorial for free, use another platform. For more information, see Heroku’s Next Chapter (opens new window).

This tutorial describes how to deploy a simple "echo" bot and a full-featured "kitchensink" bot on Heroku (opens new window) using the Messaging API SDK for Java (opens new window).

If you'd like to deploy a sample bot in another language, see the following Messaging API SDK repositories.

# Before you begin

Make sure you have the following:

# Deploy the "echo" sample bot

Follow the steps below to deploy a bot that echoes text messages that it receives.

  1. Get the channel secret and channel access token for the Messaging API channel from the LINE Developers Console.

    You may prefer to use the long-lived channel access token to build a sample bot because of its simplicity. However, in real environments, we recommend using the expiry-specified channel access token (channel access token v2.1) to enhance security.

  2. Click the Deploy to Heroku button on the README file (opens new window) in the sample-spring-boot-echo GitHub directory.

    The Create New App page in Heroku is displayed.

  3. Using the values from step 1, fill in the "App name" (optional), "LINE_BOT_CHANNEL_TOKEN", and "LINE_BOT_CHANNEL_SECRET" fields and click Deploy app. Copy the app name because it will be used in the next step. As it may take some time, wait for the app to be deployed.

    Config Vars

  4. Select the Messaging API tab of your channel settings on the LINE Developers Console.

  5. Enter the webhook URL using the following URL format: https://{HEROKU_APP_NAME}.herokuapp.com/callback
    Note: {HEROKU_APP_NAME} is the app name from step 3.

  6. Enable Use webhook.

    Messaging API settings > Webhook settings > Webhook URL

    Note

    This is set to "Disabled" by default.

  7. Add the LINE Official Account associated with your bot as a friend on LINE by scanning the QR code on the Messaging API tab of your channel settings on the LINE Developers Console.

  8. Send your LINE Official Account a text message on LINE and confirm that it responds with the same message.

The settings for Auto-reply messages and Greeting messages

When using the Messaging API, make sure that the settings for Auto-reply messages and Greeting messages on the channel are set to Disabled.

# Check logs with Heroku CLI

To see the logs of your bot on Heroku, follow the steps below.

  1. Download and install Heroku CLI (opens new window).

  2. Log in to Heroku using a terminal or a command line application.

    $ heroku login

  3. Check your logs. Note: {HEROKU_APP_NAME} is the app name from step 3 above.

    $ heroku logs --tail --app {HEROKU_APP_NAME}

# Deploy the kitchensink sample bot app

The kitchensink (opens new window) sample bot app includes the full set of features available with the Messaging API such as template and imagemap messages. To deploy the kitchensink bot, create a new Heroku app from the Heroku dashboard.

  1. Create a new channel on the LINE Developers Console and get the channel secret and channel access token. Add the LINE Official Account associated with your bot as a friend by scanning the QR code on the Messaging API tab.

  2. Clone the line-bot-sdk-java (opens new window) GitHub repository onto your local machine.

  3. Open Procfile and replace all instances of echo with kitchensink.

    // Before
web: java $JAVA_OPTS -jar sample-spring-boot-echo/build/libs/sample-spring-boot-echo-*-SNAPSHOT.jar --server.port=$PORT
// After
web: java $JAVA_OPTS -jar sample-spring-boot-kitchensink/build/libs/sample-spring-boot-kitchensink-*-SNAPSHOT.jar --server.port=$PORT

  4. Rename the application-template.yml file under sample-spring-boot-kitchensink/src/main/resources/ to application.yml. Fill in the channel-secret and channel-token fields with the values you got in step 1. Delete the part that says "This is a template for the configuration file. Make a copy called `application.yml` and change the values below."

  5. Create a new Heroku app from the Heroku dashboard and copy the app name.

  6. Go to your line-bot-sdk-java directory and add a Git™ remote. Note: {HEROKU_APP_NAME} is the app name from step 5.

    $ heroku git:remote -a {HEROKU_APP_NAME}

  7. Push changes to Heroku.

    $ git add .
$ git commit -m 'First commit'
$ git push heroku master

  8. Enter the webhook URL in the LINE Developers Console using this URL format: https://{HEROKU_APP_NAME}.herokuapp.com/callback.

  9. Try these features with your LINE Official Account on LINE:

    • Type "profile" to get your user profile.
    • Type "buttons", "confirm", or "carousel" to send a template message.
    • Type "imagemap" to send an imagemap message.
    • Invite the LINE Official Account to a group chat. Type "bye" to make it leave the group chat.
    • Send image, audio, video, or location information to the LINE Official Account. The bot then retrieves the content and sends it back to you.
Response delay

Your bot may need some time to start up after deployment. If it doesn't immediately respond to your message with the expected reply, try again after a few minutes.

# Next steps

For more information on how to develop your own bot with the Messaging API, see building a bot and the Messaging API reference.