How to identify who sent a transaction

Question

We are trying to figure out how to identify the sender (source address) of a given transaction retrieved using cardano-wallet.

Here is an example datastructure from the api. Be aware the field values are randomized (not real):

{
  inserted_at: {
    height: { quantity: 4263, unit: "block" },
    time: "2021-11-21T18:00:39Z",
    epoch_number: 190,
    absolute_slot_number: 4323,
    slot_number: 132423,
  },
  status: "in_ledger",
  withdrawals: [],
  amount: { quantity: 2000000, unit: "lovelace" },
  inputs: [
    {
      id: "80b4ab2773da9bccdb62d8bbf22f339bf041f0ff082f34acc6614f6a759e58e",
      index: 0,
    },
  ],
  direction: "incoming",
  fee: { quantity: 0, unit: "lovelace" },
  outputs: [
    {
      amount: { quantity: 2000000, unit: "lovelace" },
      address:
        "addr_test1qzwtzc4vrase42ytaj8nqam6z4322x5dx08gj2gxtjqy05wl5feqsw9lgy9askcyzjemw4d8x94n25nq204j6kqfpmhsn64us7",
      assets: [],
    },
    {
      amount: { quantity: 56, unit: "lovelace" },
      address: "addr_test1vqd00tpc537seq9hy64pupcu7s88x5w9jdln4lqyfees3swgmk",
      assets: [],
    },
  ],
  metadata: None,
  depth: { quantity: 370, unit: "block" },
  id: "d6c29eb3a8865b1e79d5cf2beb4d04b6685145a2c73d910d70e8f80080384",
  deposit: { quantity: 0, unit: "lovelace" },
  collateral: [],
  mint: [],
};

Now, the source address is listed in one of the outputs, since the transaction must send the remainder of the balance to it. However, this isn't a great way to identify the source address because it might not be there if there is no remainder, or there may be 3 or more outputs.

I expected the inputs to contain the address, but it just has an id.

I see no other mentions of the source address. How does one figure out who sent a transaction?

Answer 1

You cannot find the sender address using cardano-wallet. You will need to install cardano-db-sync for that and query it, or you will have to use an external API (like blockfrost.io) and make a call to the endpoint documented here: https://docs.blockfrost.io/#tag/Cardano-Transactions/paths/~1txs~1{hash}~1utxos/get

Answer 2

A transaction consumes UTXOs not addresses, therefore you can see the 80b4ab2773da9bccdb62d8bbf22f339bf041f0ff082f34acc6614f6a759e58e#0 which is the UTXO being consumed.

To find out the originating address, you might need to list the transaction that created this UTXO.

I do not think cardano-wallet supports finding the wallet of a given address, so you would need to look through all the wallets to find your address.

Answer 3

You can query the input transaction hash, in your case 80b4ab2773da9bccdb62d8bbf22f339bf041f0ff082f34acc6614f6a759e58e using a block explorer like cardanoscan, or from your own running node using cardano-db-sync

For example, when I search the above Tx Hash in cardanoscan, I get: https://testnet.cardanoscan.io/address/80b4ab2773da9bccdb62d8bbf22f339bf041f0ff082f34acc6614f6a759e58e

It seems like an unused address, but you mentioned the values were randomized. Try querying using the real TX hash that you are interested in. You should then be able to gather the info you need.

Answer 4

You all are way over complicating this.. It's as easy as:

def get_return_address_from_utxo(utxo):
try:
    r = requests.get(f"https://cardanoscan.io/transaction/{utxo}")

    content = r.content.decode("utf-8").split(
        'FROM ADDRESSES (INPUTS)</span></div></div><div class=mt-4><div class="d-flex flex-row '
        'justify-content-between px-3"><div><strong>Address</strong></div><div><strong>Amount</strong></div></div><hr class=darkHR><div data-simplebar><div class="d-flex flex-row justify-content-between px-2"><div class=addressField><div class="row align-items-center"><div class=col-auto>')
    sub = content[1].split("span")
    address = sub[0]
    address = address.replace("<a href=/address/", "").replace("><", "")
    return address
except requests.exceptions.RequestException as e:
    return ''
except IndexError as e:
    return ''

Answer 5

You can use db-sync. I wrote an article about how to do it on Medium

How to identify who sent a Cardano transaction using db-sync