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Elrond has events that can be emitted during smart contract execution: https://docs.elrond.com/developers/developer-reference/elrond-wasm-annotations/#events

How would I query for or subscribe to these events? On Ethereum, it would be possible to monitor/query such events as they execute using web3 or the Ethereum client node RPC. Is there something similar on Elrond?

Annatar
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1 Answers1

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You have a few ways to use those events.

  1. You can use the api to fetch transactions for an account and then use the transaction endpoint to get more details for those transactions and read the events.

    The endpoint would be: http://testnet-gateway.elrond.com/transaction/<txhash>?withResults=true

    (Note: Event data and smart contract results will only be returned if you add the ?withResults=true query param)

  2. You can also use the transaction processor package to process all transactions that are notarized on the blockchain and again get the event data using the transaction endpoint.

  3. Those events are also indexed in the elastic search instance so you can use elastic search to query for information. Either by setting up your own observer-squad with elastic search or by using the public indexer. (https://testnet-index.elrond.com/logs/_search)

Martin W
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  • Cool! Are there docs available for the transaction processor package or elastic search? For elastic search I saw (https://docs.elrond.com/sdk-and-tools/elastic-search/) but it does not contain much detail – Annatar Oct 05 '21 at 21:24
  • @Annatar To be honest I'm not to sure about elastic search myself, it's a big topic. But I guess elastic search does have a way to find out which data was indexed and surely you will find some docs for elastic search if you search the internet :) – Martin W Oct 07 '21 at 21:32