Checking that Ethereum output was spent -e
The Block Chain Book, which is based on Ethereum, ensures that a transaction output has been spent. In this article, we examine how to check that an Ethereum output was spent using an RPC client.
What is UTXO?
Before we get into the solution, we will quickly discover the UTXO (unpaid transaction output). UTXO represents a transaction that has not yet been spent or permanently carried out and contains all the information required for it. It consists of the following:
- The
txid(transaction ID)
- The
vsize" (number of transaction inputs)
- The “NexMints” (the number of the mint in the transaction, ie it spends the sum of each output)
- A series of "txinrange" titles in the transaction
RPC client
We use a RPC client like Bitcoin-Cli to execute the check. You can install it on the Ethereum node or download it as a separate device.
Bash
Install Bitcoin-Cli (for most Linux distribution)
sudo apt-get update && sudo apt-get install bitcoin-cli
On Windows:
git clone
CD Go-Ethreum
Make.exe build-deps && make.exe release
./Release/Bin/bitcoin-cli —jsonrpc = 1
`
Example Code
Here’s an example of how to use the RPC client to check that they spent an output:
`Python
Import Json
Def get_transection_output (tx_hash, index):
Get the transaction output from the blockchain
Answer = Bitcoin-Cli.gettransectionoutput (tx_hash)
Analyze the json answer
output = json.loads (reply [‘result’])
Check out the output utxo -e is -e and this was spent -e
utxo = next ((o o o in the output [‘outputs’] if o [‘type’] == ‘release’), no)
If not utxo or utxo [‘minta’]! = Index:
restore
If it’s a release, check that the transaction has been final -e
txhash = bitcoin_cli.gettransectionoutput (tx_hash) [‘txid’]
Answer = Bitcoin-Cli.getblockbynumber (0)
Get the latest block
block = json.loads (reply [‘result’])
in block in the block [‘blocks’]:
To the output in the block [‘outputs’]:
If output [‘type’] == ‘release’ and utxo [‘minta’] == index:
restore
Return
Using examples
tx_hash = “0x1234567890ABCDEF”
Replace the actual transaction hash
Index = 10
Replace the desired expense index (0-index)
Result = get_transection_output (tx_hash, index)
Print (“Output was spent”, result)
output: true or false
`
Conclusion
Checking the Ethereum output output is a critical step in understanding how to handle the blockchain. If you take advantage of an RPC client, such as Bitcoin-Cli, you can easily check that an output has been spent by analyzing the JSON response and checking relevant information.
Remember to replace the “tx_hash” and “index” variables for the actual values of the Ethereum transaction or release. This example uses a simple string-based approach, but it may not cover all the lives. In real scenarios, you are likely to use more robust analytical techniques to manage possible changes in the output structure and complexity.