What are the differences between request-reply and publish-subscribe messaging patterns?

What are the differences between request-reply and publish-subscribe messaging patterns?

Request-reply is a direct communication pattern where a sender requests information and waits for a response. In contrast, publish-subscribe allows multiple subscribers to receive messages published by a sender without direct communication.

Can you give me an example of each?

Sure! In request-reply, a client might ask a server for the current weather, and the server responds with the data. In publish-subscribe, a weather station publishes updates, and all subscribed users receive those updates without asking.

Which pattern is better for real-time applications?

Publish-subscribe is often better for real-time applications because it allows for immediate updates to all subscribers without the need for each one to request information.

Are there any downsides to using publish-subscribe?

Yes, potential downsides include increased complexity in managing subscriptions and the possibility of message loss if subscribers are not connected when messages are published.