The filter2 application is a basic example app that demonstrates how to subscribe to and publish messages using waku2-filter
make
To start the filter2 application run the following from the project directory
./build/filter2
The app will run 2 nodes ("full" node and "light" node), with light node subscribing to full node in order to receive filtered messages.
- A light node is created with option WithWakuFilterLightNode.
- Starting this node sets stream handler on wakunode.Host for WakuFilterProtocolId.
- Light node submits a FilterSubscribeRequest through WakuFilterLightNode.Subscribe. This request is submitted to a particular peer. Filter is stored in WakuFilterLightNode.subscriptions map. That's it.
- Now we wait on WakuFilterLightNode.onRequest to process any further messages.
- On receiving a message check and notify all subscribers on relevant channel (which is part of subscription object).
- If a broadcaster is specified, WakuNode.Subscribe has a message loop extracting WakuMessages from a wakurelay.Subscription object. It denotes a pubsub topic subscription. All envelopes are then submitted to node.broadcaster.
- Full node is created with option WithWakuFilterFullNode.
- We read incoming messages in WithWakuFilterFullNode.onRequest(). It is set as a stream handler on wakunode.Host for WakuFilterProtocolId.
- In WakuFilter.onRequest
- We check the type of FilterRequest and handle accordingly.
- If it's a FilterRequest for subscribe, add a subscriber.
- If it is a SubscriberPing request, check if subscriptions exists or not and respond accordingly.
- If it is an unsubscribe/unsubscribeAll request, check and remove relevant subscriptions.