Connect to the CKB RPC and mempool API using WebSockets

[Flouse]

The CKB RPC server and mempool.space support WebSocket connections

• https://github.com/nervosnetwork/ckb/blob/c5671a12c3039d9ee376468e813cfbee08677386/rpc/src/server.rs#L56-L64

• https://mempool.space/docs/api/websocket

[ahonn]

I did think about that before, but I haven't gotten around to making it happen yet.
The websocket on mempool.space seems more suitable for monitoring, and since electrs doesn't have websocket support. So, I haven't thought about adding it for now.
As for the CKB RPC websocket part, we can consider replacing it later on, but that's still up in the air.

[Flouse]

And this is just my thought after a recent code review. It should only be implemented when the benefits are clear.

The websocket on mempool.space seems more suitable for monitoring, and since electrs doesn't have websocket support. So, I haven't thought about adding it for now.

That makes sense.

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When we want to monitor RBF transactions, the websockets of mempool.space might be useful.

• ref: BTC Replace by Fee (RBF) feature: Allow a BTC transaction to be replaced with a higher fee rgbpp-sdk#82 (comment)

[ahonn]

When we want to monitor RBF transactions, the websockets of mempool.space might be useful.

• ref: BTC Replace by Fee (RBF) feature: Allow a BTC transaction to be replaced with a higher fee rgbpp-sdk#82 (comment)

IMO, When tracking RBF transactions, we only need to monitor unconfirmed RGB++ BTC transactions. When processing the RGB++ CKB transaction, I like to use https://mempool.space/testnet/docs/api/rest#get-transaction-rbf-history to access a transaction's RBF history. This way, we can obtain the RBF history of an unconfirmed transaction and queue a new transaction based on the updated RBF transaction.