line-bot-development

When to use this skill

Use this skill when you need to:

• Develop or modify LINE Bot webhook handlers
• Implement new bot commands and message responses
• Handle LINE events (messages, join/leave groups)
• Integrate LINE Messaging API features
• Debug LINE Bot webhook issues
• Test bot functionality in LINE groups

How to use it

Core Components

1. LINE Bot SDK Setup

Use the LINE Bot SDK v3 for Python:

from linebot.v3.messaging import MessagingApi, Configuration, ApiClient
from linebot.v3.webhook import WebhookHandler, MessageEvent
from linebot.v3.messaging.models import PushMessageRequest, TextMessage
from linebot.v3.webhooks import TextMessageContent, JoinEvent, LeaveEvent

2. Environment Configuration

Required environment variables:

• LINE_CHANNEL_ACCESS_TOKEN - Bot access token from LINE Developers Console
• LINE_CHANNEL_SECRET - Channel secret for webhook verification
• LINE_GROUP_ID (optional) - Comma-separated group IDs for broadcasting

3. Webhook Handler Pattern

@app.route("/callback", methods=['POST'])
def callback():
    signature = request.headers['X-Line-Signature']
    body = request.get_data(as_text=True)
    
    try:
        handler.handle(body, signature)
    except Exception as e:
        abort(400)
    
    return 'OK'

@handler.add(MessageEvent, message=TextMessageContent)
def handle_message(event):
    # Process user messages
    pass

@handler.add(JoinEvent)
def handle_join(event):
    # Handle bot joining a group
    pass

@handler.add(LeaveEvent)
def handle_leave(event):
    # Handle bot leaving a group
    pass

4. Message Sending

# Reply to user message
messaging_api.reply_message(
    ReplyMessageRequest(
        reply_token=event.reply_token,
        messages=[TextMessage(text="Response text")]
    )
)

# Push message to group
messaging_api.push_message(
    PushMessageRequest(
        to=group_id,
        messages=[TextMessage(text="Broadcast message")]
    )
)

5. Command Pattern

Implement commands with @ prefix:

def handle_message(event):
    text = event.message.text.strip()
    
    if text.startswith('@'):
        parts = text[1:].split()
        command = parts[0].lower()
        args = parts[1:] if len(parts) > 1 else []
        
        if command == 'help':
            # Show help
        elif command == 'schedule':
            # Show schedule
        # ... more commands

Best Practices

1. Group Context Awareness

   • Always extract group_id from events
   • Store per-group configurations separately
   • Validate group permissions before operations

2. Error Handling

   • Wrap webhook handlers in try-except blocks
   • Log errors for debugging
   • Send user-friendly error messages back to LINE

3. Message Formatting

   • Use emojis to enhance UX (🗑️, 📅, 👥, etc.)
   • Keep messages concise and scannable
   • Use line breaks for readability

4. Testing

   • Test commands in a dedicated LINE group
   • Verify webhook signature validation
   • Check response times (should be quick)

Common Patterns

Multi-Group Support

# Get group ID from event
group_id = event.source.group_id if hasattr(event.source, 'group_id') else None

# Load group-specific data
group_data = groups.get(group_id, {})

Scheduled Broadcasting

from apscheduler.schedulers.background import BackgroundScheduler

def send_reminder(group_id):
    # Get group-specific schedule
    # Send reminder message
    pass

scheduler = BackgroundScheduler()
scheduler.start()

Reference Links

• LINE Developers Console
• LINE Messaging API Documentation
• LINE Bot SDK for Python