LINE Messaging API SDK for Python

3.23.0 · active · verified Thu Apr 09

The `line-bot-sdk` is the official Python SDK for interacting with the LINE Messaging API. It simplifies the development of LINE bots by providing classes for sending messages, handling events, and managing user interactions. The current version is 3.23.0, and it maintains a frequent release cadence, often with monthly or bi-monthly updates to support new API features.

Warnings

breaking Upgrading from `line-bot-sdk` v2.x to v3.x introduced significant breaking changes, including refactored `LineBotApi` instantiation, changes to `WebhookHandler` setup, and updated module paths for event and message models.
Fix: Review the official migration guide for v3.x. Update `LineBotApi` imports (e.g., `from linebot import LineBotApi`), `WebhookHandler` instantiation, and imports for `linebot.models` classes.
breaking All LINE Things related webhook code (e.g., `ThingsEvent`, `ThingsContent`, `LinkThingsContent`) was removed due to the LINE Things service shutdown. Although released as a patch version, this is a breaking change for applications using these features.
Fix: Remove any code referencing `ThingsEvent` or related LINE Things models. These functionalities are no longer supported by the LINE Messaging API.
gotcha Webhook signature verification is enabled by default and is crucial for security. However, misconfiguration or local development setups can lead to `InvalidSignatureError`. The `WebhookHandler` will raise this error if the signature cannot be verified.
Fix: Ensure your `LINE_CHANNEL_SECRET` is correct and matches the one configured in your LINE Developers console. For local development or specific scenarios, v3.19.1+ introduced an option to skip verification during handler initialization: `WebhookHandler(channel_secret, skip_events_signature_verification=True)` (use with caution in production).

Install

pip install line-bot-sdk Install latest version

Imports

LineBotApi
```
from linebot import LineBotApi
```
WebhookHandler
```
from linebot import WebhookHandler
```
MessageEvent
```
from linebot.models import MessageEvent
```
TextMessage
```
from linebot.models import TextMessage
```

TextSendMessage

from linebot.models import TextSendMessage

InvalidSignatureError

from linebot.exceptions import InvalidSignatureError

LineBotApi (old)
```
from linebot import LineBotApi
```
In v3.x, the LineBotApi class moved directly under the `linebot` namespace, removing the intermediate `.api` module found in v2.x.

Quickstart

This Flask example sets up a basic LINE webhook. It receives messages, verifies the signature, and replies with the user's message. Ensure `LINE_CHANNEL_SECRET` and `LINE_CHANNEL_ACCESS_TOKEN` environment variables are set. This snippet requires Flask to be installed (`pip install Flask`).

import os
from flask import Flask, request, abort

from linebot import (
    LineBotApi, WebhookHandler
)
from linebot.exceptions import (
    InvalidSignatureError
)
from linebot.models import (
    MessageEvent, TextMessage, TextSendMessage
)

app = Flask(__name__)

# Get channel_secret and channel_access_token from environment variable
channel_secret = os.environ.get('LINE_CHANNEL_SECRET', '')
channel_access_token = os.environ.get('LINE_CHANNEL_ACCESS_TOKEN', '')

if not channel_secret:
    print('Specify LINE_CHANNEL_SECRET as environment variable.')
    exit(1)
if not channel_access_token:
    print('Specify LINE_CHANNEL_ACCESS_TOKEN as environment variable.')
    exit(1)

line_bot_api = LineBotApi(channel_access_token)
handler = WebhookHandler(channel_secret)

@app.route("/callback", methods=['POST'])
def callback():
    # get X-Line-Signature header value
    signature = request.headers['X-Line-Signature']

    # get request body as text
    body = request.get_data(as_text=True)
    app.logger.info("Request body: " + body)

    # handle webhook body
    try:
        handler.handle(body, signature)
    except InvalidSignatureError:
        print("Invalid signature. Please check your channel access token/channel secret.")
        abort(400)

    return 'OK'


@handler.add(MessageEvent, message=TextMessage)
def handle_message(event):
    line_bot_api.reply_message(
        event.reply_token,
        TextSendMessage(text=f"You said: {event.message.text}")
    )


if __name__ == "__main__":
    app.run(port=8000)

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