Show the spending transaction of spent outputs #356
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Rebased ! |
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0499abe add batch JSON request to electrum server to collect all spending transactions of all outpoints in one Electrum call. I didn't use My problem is that the second parameter must be the same for all batched JSON and I can't pass an outpoint as first argument into it because |
| contents.push(request); | ||
| arguments_far_calls[id] = outpoint; | ||
| } | ||
| const content = '[' + contents.join(',') + ']'; |
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Why do you use string manipulation instead of native Json encoding?
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The honest answer is that this is how it was made fore requestBatch in electrum-client lib x')
The write method for net.socket must take a string https://nodejs.org/api/net.html#net_socket_write_data_encoding_callback
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I notice that there exist transactions that have so many outputs that ElectRS takes too much time to answer so it may be worth adding some limitation on the number of outputs before showing the spending transaction of all outpoints. An example of such heavy transactions: d22c53dd5a79fb6cc7a10ed6531761ae43ce1ce2ecd1ebbc5746ba82c71e6d70 |
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No wonder, that transaction got blockstream.info (which uses even more efficient implementation) stuck too. Could it be loaded asynchronously? Show the page, load outputs chunk-by-chunk (20 at a time or something) and show them as the data arrive. But ultimately I'd like it to be profiled and try to find if there's a reasonable optimization for |
Seems to work for me: https://blockstream.info/tx/d22c53dd5a79fb6cc7a10ed6531761ae43ce1ce2ecd1ebbc5746ba82c71e6d70 |
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Ah, works for me too now. Was probably a fluke. |
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link to outpoint page if too many Outpoint status in others tx display
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The last commit adds a limit of 200 to the number of outpoints of a transaction for which we fetch the spending transactions to show them along with the numbers of blocks between the transaction and the spending of an outpoint. This is to prevent the Electrum server from DDoS because of heavy transactions with many outputs (such transactions can generally be found as two hops spending transactions of coinbase outputs). When there are too may outpoints, the explorer will just provide a link for each spent outpoint to a new page on the outpoint. This page will ask to the electrum server for the spending transaction and return its paget if it exists with a message telling the user which outpoint he is looking at and how many block between its creation and spending. If the spending transaction doesn't exist, it will return the funding transaction page with a message to inform the outpoint is not spent. When looking at a transaction in the explorer from a panel not in a transaction page (from mempool section or blocks content or address history), we also provide a link to the outpoint page of each outpoint of each transactions shown. However, we cannot tell if an outpoint is spent in advance or not so the link presence doesn't garantee the outpoint is spent which is why it reads "Outpoint Status" (spent or unspent). This reduces the need for spesmilo/electrumx#90 (comment) @Kixunil Things are a bit mess up when the Electrum server doesn't support Electrum 1.5 (the explorer still display a link to outpoint statuseven if not supported...). I didn't find a good fix for now but it should be straightforward. |
Solve #270
Requirements: Electrum server supporting Electrum 1.5 method
blockchain.outpoint.subscribeTo activate this option you must set
BTCEXP_ELECTRUM_TXINDEX = truein.envfile as if you want to query ElectRS txindexing.ElectRS 0.9.0 will support this method thanks to romanz/electrs/pull/446
This means this PR should not be merged until spesmilo/electrumx/pull/90 is merged
Screenshots time !
A transaction with many outputs to "bench" loading speed : 7cdaf30c42eac0271108fe0aa170a02a31f729fb10079156f06611f0489f8f67
BTC-RPC-Explorer needs to make one
blockchain.outpoint.subscribecall for each spent transaction output (no call for UTXOs). There are around 250 spent outputs in this transaction at the time I wrote this PR, I load it in less than 40 secondes on my RPi (blockchain stored on HDD).A random transaction with outputs in the mempool at the time I wrote this PR (for easy copy-pasting txid = 6f949c749d890a250a40c29ca8c97576d47eca7f113980f65a0c62fb330516a1 )
The txid of spending transaction is clickable link and redirect to the explorer page of the sending transaction.
Electrum 1.5 specifications say that
blockchain.outpoint.subscribemust subscribe the client to notification of changing state of the outpoint (spend, unspend, maybe reorg). We only need the output of this method so I unsubscribe the explorer immediatly after collecting it to avoid spamming the electrum server of subscriptions. ElectRS doesn't implement subscriptions for now so the unsubscribe method will fail, but this can be ignored.