Handling events

Events are actions that happen in your Switch account (incoming messages, new members join, bot button presses, etc.), and you can use them to trigger actions in your bot.

To listen to an event, you need to register event handlers.

Each handler deals with a specific event and once a matching update arrives from the app, your registered callback function will be called back by the framework and its body executed.

Registering a handler

To explain how handlers work let’s examine the one which will be in charge for handling Message updates coming from all around your chats. Every other kind of handler shares the same setup logic and you should not have troubles settings them up once you learn from this section.

Using decorators

The most elegant way to register a message handler is by using the on_message() decorator:

from swibots import Client, BotContext, MessageEvent

app = Client("TOKEN")

@app.on_message()
async def message_handler(ctx: BotContext[MessageEvent]):
   await ctx.event.message.reply_text(f"Thank you! I received your message: {ctx.event.message.message}")

app.run()

The defined function message_handler, which accepts one argument (ctx, of type BotContext[MessageEvent]), will be the function that gets executed every time a new message arrives.

In the last line we see again the run() method, this time used without any argument. Its purpose here is simply to automatically start(), keep the app online so that it can listen for updates and stop() it once you hit CTRL+C.

Using the add_handler() method

If you prefer to use the add_handler() method instead of the decorator, you can do so by calling add_hanlder of the app with an instance of MessageHandler object:

from swibots import Client, BotContext, MessageEvent, MessageHandler

app = Client("TOKEN")

async def handle_message(ctx: BotContext[MessageEvent]):
    await ctx.event.message.reply_text(f"Thank you! I received your message: {ctx.event.message.message}")

app.add_handler(MessageHandler(handle_message))

app.run()