feat: return providing peer(s) in bitswap:want-block:block event

[SgtPooki]

Question

Using Helia, when I download the contents of a CID, could I easily see which node I ultimately retrieved the data from? How would I do that?

• @TheDiscordian

Answer

This could be added to bitswap - the hasBlock method here would need the id of the providing peer added as an argument, then the bitswap:want-block:block event could hold both the CID of the incoming block and the providing peer when it's emitted here.

It's worth noting that if the DAG referenced by a CID is made from multiple blocks, these blocks could come from different peers, so it'd be more like "which node(s)" rather than "which node".

• @achingbrain

This question came across in ip-js channel on slack: https://filecoinproject.slack.com/archives/C046HDAHA13/p1689877647075909

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