TS: Support Blockstream's Esplora/Electrs servers for electrum protocol integration #501
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As Esplora/Electrs doesn't support verbose transactions details in the response, that would contain the confirmations number we need to workaround it. (See: Blockstream/electrs#36) The workaround: 1. Get the raw transaction 2. Deserialize the raw transaction 3. Find transaction block height by finding it in a history of transactions for the output script included in the transaction. 4. Get the latest block height 5. Calculate number of confirmations by subtracting the transaction block height from the latest block height and adding one.
The simpliest solution is to request verbose format of transaction. Unfortunatelly it's not compatible with Esplora/Electrs implementation of ElectrumX server. (see: Blockstream/electrs#36) As a workaround to cover integration with Esplora/Electrs we get a raw transaction and deserialize it.
We can test exact block number, not only it being greater than 6. For that we need to fetch the current block height to compare it with the one we get. We use blockstream as a source of truth.
We can test electrum integration against different kinds of servers. The most popular implementations are: - ElectrumX - Fulcrum - Electrs/Esplora We can find list of public servers here: https://1209k.com/bitcoin-eye/ele.php?chain=tbtc The electrs-esplora server seems pretty unstable, so we don't want to enable it in tests untill we add retries.
Before a7aedd1 under these two properties we returned exactly the valu that was retruned from electrum server. This was causing some unexpected bahaviour as it could happen that different implementation and instances of servers were returning different results. The only thing that we can relay on is a hex value for bytes that were used in the transaction. Here we switch to hexadecimal value to have consistent behaviour and be able to support all major electrum server implementations (ElectrumX, Electrs/Esplora and Fulcrum). The change here is similiar to what we implemented in the Keep Client.
The servers are working now, so we can try enabling the tests. We still need to work on stable results for electrs-esplora server.
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An alternative approach that I would also like to investigate would be to use verbose transactions as before and fallback to the logic proposed in this PR only in case verbose is not supported by the server. |
I tested it and it did not result in any improvement in test execution time. This is probably as if we get verbose transactions the processing has to be done on the server side. Let's leave it as is and update it in the future if necessary. |
Interesting, I would've expected verbose transactions to perform better than fetching the entire address history and looking it up there. Which electrum server implementation did you benchmark this against? Did you try with transactions that use reused addresses, such that looking up the address returns other historical transactions too? (For example |
Closes: #422
In this PR we update the implementation of TypeScript Electrum integration to support Esplora/Electrs servers.
As per Blockstream/electrs#36 verbose transactions are not supported by Esplora/Electrs.
This affects our implementation of
getTransactionandgetTransactionConfirmationsfunctions.For a consistent code in the client without alternative paths for different Electrum servers implementations I decided to not use verbose transactions at all.
getTransactionConfirmations
transactions for the output script included in the transaction.
block height from the latest block height and adding one.
getTransaction
We get a raw transaction and deserialize it with
bcoin. This lets us define a consistent type for returned transactions (093d4ec). Before these changes, I observed that Electrum server implementations are not consistent with data returned in verbose JSON.Electrum tests
We can test electrum integration against different kinds of servers.
The most popular implementations are:
We can find a list of public servers here: https://1209k.com/bitcoin-eye/ele.php?chain=tbtc
The electrs-esplora server seems pretty unstable, so we don't want to enable it in tests until we add retries (#485).