Filter for utxos that was send from a specific public key address

Question

In the pionner program they have this logic where they filter through utxos and get a specific set of utxos.

{...}
utxos <- Map.filter (isSuitable pkh) <$> utxosAt scrAddress
{...}
where
   isSuitable :: PubKeyHash -> TxOutTx -> Bool

How can i modify this to make it so that it filters utxos that came from a specific public key address. Basically get all utxos sitting in a script address that came from a specific public key.

Answer 1

Assuming each UTxO at the script address has a datum that contains the PubKeyHash you can compare against, then you can use the above code like so:

data UTxODatum = UTxODatum
    { pubKey :: !PaymentPubKeyHash }

{...}
    isSuitable :: PaymentPubKeyHash -> ChainIndexTxOut -> Bool
    isSuitable pkh o = case getUTxODatum o of
        UTxODatum{pubKey=pubKey} -> pubKey == <your specific pkh>
        _                        -> traceError "Unhandled datum type"
{...}

getUTxODatum :: ChainIndexTxOut -> UTxODatum
getUTxODatum o = case _ciTxOutDatum o of
    Left _ -> traceError "unexpected datum"
    Right (Datum d) -> do
        let parsedDatum = PlutusTx.fromBuiltinData d :: Maybe UTxODatum
        case parsedDatum of
            Just s -> s
            _ -> traceError "Unknown datum type"