How to get sender address from transaction with JSON RPC?

Question

I'm using JSON-RPC call to connect to local bitcoin node on my clouding server.

I could get all transactions with wallet name by using gettransactions. Now I need to get sender's address for each transaction but result contains only receivers' address.

Following is response of gettransactions request.

{
    "result": [
        {
            "address": "bc1qd9mgd4ynryaw2kp0pzfjdxguhz9dzvs5vh0nfn",
            "category": "receive",
            "amount": 0.001,
            "label": "",
            "vout": 27,
            "confirmations": 1322,
            "blockhash": "000000000000000000074551080f954e790edfe6ad810ecebf4691e881175eaf",
            "blockheight": 660029,
            "blockindex": 106,
            "blocktime": 1607147554,
            "txid": "07ab59c8d3a204172887085258460d0058c20a9acdb451daa5ad4290cbd461b0",
            "walletconflicts": [],
            "time": 1607147511,
            "timereceived": 1607147511,
            "bip125-replaceable": "no"
        },
        {
            "address": "bc1q6dh3h5e3qgku8u9s8y664844fj4fkm08n7cnwt",
            "category": "receive",
            "amount": 0.0011,
            "label": "",
            "vout": 9,
            "confirmations": 1313,
            "blockhash": "00000000000000000000960f4476a8552cac203eec6e0f826886b41fae402bec",
            "blockheight": 660038,
            "blockindex": 393,
            "blocktime": 1607153799,
            "txid": "af0885e4c1d10e935de525680c6c33d221ab506742b08e34a0322bba90b56fb0",
            "walletconflicts": [],
            "time": 1607152236,
            "timereceived": 1607152236,
            "bip125-replaceable": "no"
        },
        {
            "address": "1L8ZNCibVVpPjJ8VJ1ALLuTjtctA4mzGPw",
            "category": "send",
            "amount": -0.001,
            "vout": 0,
            "fee": -0.00008536,
            "confirmations": 706,
            "blockhash": "0000000000000000000c3230522e267980bb990883cc0b36460ad3efc1f8fed4",
            "blockheight": 660645,
            "blockindex": 1049,
            "blocktime": 1607529332,
            "txid": "a2056e7a49bc608435713519bc038ed7da2e65f588495f36c6628f5ca6fe2d7d",
            "walletconflicts": [],
            "time": 1607528963,
            "timereceived": 1607528963,
            "bip125-replaceable": "no",
            "comment": " ",
            "to": "seans outpost",
            "abandoned": false
        },
        {
            "address": "1L8ZNCibVVpPjJ8VJ1ALLuTjtctA4mzGPw",
            "category": "send",
            "amount": -0.0005,
            "vout": 1,
            "fee": -0.00008536,
            "confirmations": 705,
            "blockhash": "0000000000000000000994e21412109847caffa2bd990884f49461d53c047055",
            "blockheight": 660646,
            "blockindex": 844,
            "blocktime": 1607529675,
            "txid": "ddbe1dce4537926b6cf5bc1e222e5cd32de224cf346ca89251c127ce32226f30",
            "walletconflicts": [],
            "time": 1607529401,
            "timereceived": 1607529401,
            "bip125-replaceable": "no",
            "comment": " ",
            "to": "seans outpost",
            "abandoned": false
        }
    ],
    "error": null,
    "id": "curltest"
}

How can I get sender's address?

Answer 1

Despite how it looks on most block explorers, Bitcoin doesn't really have a concept of a "sender address", at least not on the raw transaction level. What a transaction has is inputs and what block explorers do is go look up those inputs and guess the address that was used to create those UTXOs.

You might find these related questions useful (just search this site for "sender address"):

How to findout the sender of a transaction

Sender address from DecodeRawTransaction (C#)

Answer 2

To get the sender address from Bitcoin Core, you will have to track additional information about the blockchain by setting txindex=1 in the configuration file. This is because the sending address of the transaction in question is only associated with the previous transaction. Setting txindex=1 configures Bitcoin Core to maintain the entire transaction index, beyond what pertains to your wallet or read-only addresses, allowing you to call getrawtransaction on any txid.

Once you have properly configured and synced Bitcoin Core, you can retrieve the sending address(es) of a transaction by looking through each input tx using decoderawtransaction(getrawtransaction(txid)) (code pulled from this answer):

txid = <relevant transaction id>
addresses = []
raw_tx = decoderawtransaction(getrawtransaction(txid))
for(input in raw_tx['vin']) {
  input_raw_tx = decoderawtransaction(getrawtransaction(input['txid']))
  addresses.push(input_raw_tx['vout'][input['vout']]['scriptPubKey']['addresses'][0])
}

Many blockchain explorers have free low-volume API access and you can just query their data instead of maintaining a full txindex node. Two that come to mind are Blockchair and BlockCypher (BlockCypher even includes all the sender addresses in their tx endpoint so you can retrieve these with a single API call instead of querying each input tx from Blockchair like you would need to with Bitcoin Core).