There are two mutually exclusive ways of receiving updates for your bot — the long polling using
getUpdates method on one hand and Webhooks on the other. Telegram is queueing updates until the bot receives them either way, but they will not be kept longer than 24 hours.
With long polling, the client requests information from the server using
getUpdatesmethod, but with the expectation the server may not respond immediately. If the server has no new information for the client when the poll is received, instead of sending an empty response, the server holds the request open and waits for response information to become available. Once it does have new information, the server immediately sends a response to the client, completing the request. Upon receipt of the server response, the client often immediately issues another server request.
Setting a webhook means you supplying Telegram with a location in the form of an URL, on which your bot listens for updates. Telegram need to be able to connect and post updates to that URL. To be able to handle webhook updates you'll need a server that:
- Supports IPv4, IPv6 is currently not supported for webhooks.
- Accepts incoming POSTs from subnets 22.214.171.124/20 and 126.96.36.199/22 on port 443, 80, 88, or 8443.
- Is able to handle TLS1.2(+) HTTPS-traffic.
- Provides a supported, non-wildcard, verified or self-signed certificate.
- Uses a CN or SAN that matches the domain you’ve supplied on setup.
- Supplies all intermediate certificates to complete a verification chain.
You can find more useful information on setting webhook in Marvin's Marvellous Guide to All Things Webhook
Each user interaction with your bot results in new Update object. Its fields will be set depending on update type.