From 5c21a01b68b1e358238815397e0a1839842e8fe0 Mon Sep 17 00:00:00 2001
From: sairajzero <sairaj0630@gmail.com>
Date: Fri, 17 Sep 2021 02:25:16 +0530
Subject: [PATCH] floBlockchainAPI v2.1.1

- improved sendTx to check if the utxo is already used but unconfirmed (ie, still in mempool) and ignore those utxos.
This allows users to send multiple tx from the same floID without the need to wait for confirmation of prev tx as long as enough utxos are available.

- Optional parameter: strict_utxo (boolean): Default=true (safe mode).
If false, allows unconfirmed UTXOs to be included in the txn.
This will allow users to chain send tx as long as enough balance FLO is available.
WARNING: if one tx in the chain is dropped, all next tx dependent on that tx will be dropped too.

- writeData (as it invokes sendTx) also have the above improvements
---
 standard_Operations.html | 98 +++++++++++++++++++++++-----------------
 1 file changed, 57 insertions(+), 41 deletions(-)

diff --git a/standard_Operations.html b/standard_Operations.html
index cef8267..0f4e69f 100644
--- a/standard_Operations.html
+++ b/standard_Operations.html
@@ -7290,7 +7290,7 @@ Bitcoin.Util = {
         }
     }
 </script>
-<script id="floBlockchainAPI" version="2.1.0">
+<script id="floBlockchainAPI" version="2.1.1">
     /* FLO Blockchain Operator to send/receive data from blockchain using API calls*/
     const floBlockchainAPI = {
 
@@ -7355,57 +7355,75 @@ Bitcoin.Util = {
         },
 
         //Write Data into blockchain
-        writeData: function(senderAddr, data, privKey, receiverAddr = floGlobals.adminID) {
+        writeData: function(senderAddr, data, privKey, receiverAddr = floGlobals.adminID, strict_utxo = true) {
             return new Promise((resolve, reject) => {
                 if (typeof data != "string")
                     data = JSON.stringify(data);
-                this.sendTx(senderAddr, receiverAddr, floGlobals.sendAmt, privKey, data)
+                this.sendTx(senderAddr, receiverAddr, floGlobals.sendAmt, privKey, data, strict_utxo)
                     .then(txid => resolve(txid))
                     .catch(error => reject(error))
             });
         },
 
         //Send Tx to blockchain 
-        sendTx: function(senderAddr, receiverAddr, sendAmt, privKey, floData = '') {
+        sendTx: function(senderAddr, receiverAddr, sendAmt, privKey, floData = '', strict_utxo = true) {
             return new Promise((resolve, reject) => {
                 if (!floCrypto.validateASCII(floData))
                     return reject("Invalid FLO_Data: only printable ASCII characters are allowed");
-                if (!floCrypto.validateAddr(senderAddr))
-                    reject(`Invalid address : ${senderAddr}`);
+                else if (!floCrypto.validateAddr(senderAddr))
+                    return reject(`Invalid address : ${senderAddr}`);
                 else if (!floCrypto.validateAddr(receiverAddr))
-                    reject(`Invalid address : ${receiverAddr}`);
-                if (privKey.length < 1 || !floCrypto.verifyPrivKey(privKey, senderAddr))
-                    reject("Invalid Private key!");
+                    return reject(`Invalid address : ${receiverAddr}`);
+                else if (privKey.length < 1 || !floCrypto.verifyPrivKey(privKey, senderAddr))
+                    return reject("Invalid Private key!");
                 else if (typeof sendAmt !== 'number' || sendAmt <= 0)
-                    reject(`Invalid sendAmt : ${sendAmt}`);
-                else {
-                    var trx = bitjs.transaction();
-                    var utxoAmt = 0.0;
-                    var fee = floGlobals.fee;
-                    this.promisedAPI(`api/addr/${senderAddr}/utxo`).then(utxos => {
-                        for (var i = utxos.length - 1;
-                            (i >= 0) && (utxoAmt < sendAmt + fee); i--) {
-                            if (utxos[i].confirmations) {
-                                trx.addinput(utxos[i].txid, utxos[i].vout, utxos[i]
-                                    .scriptPubKey)
-                                utxoAmt += utxos[i].amount;
-                            } else break;
-                        }
-                        if (utxoAmt < sendAmt + fee)
-                            reject("Insufficient FLO balance!");
-                        else {
-                            trx.addoutput(receiverAddr, sendAmt);
-                            var change = utxoAmt - sendAmt - fee;
-                            if (change > 0)
-                                trx.addoutput(senderAddr, change);
-                            trx.addflodata(floData.replace(/\n/g, ' '));
-                            var signedTxHash = trx.sign(privKey, 1);
-                            this.broadcastTx(signedTxHash)
-                                .then(txid => resolve(txid))
-                                .catch(error => reject(error))
-                        }
+                    return reject(`Invalid sendAmt : ${sendAmt}`);
+
+                //get unconfirmed tx list
+                this.promisedAPI(`api/addr/${senderAddr}`).then(result => {
+                    this.readTxs(senderAddr, 0, result.unconfirmedTxApperances).then(result => {
+                        let unconfirmedSpent = {};
+                        for (let tx of result.items)
+                            if (tx.confirmations == 0)
+                                for (let vin of tx.vin)
+                                    if (vin.addr === senderAddr) {
+                                        if (Array.isArray(unconfirmedSpent[vin.txid]))
+                                            unconfirmedSpent[vin.txid].push(vin.vout);
+                                        else
+                                            unconfirmedSpent[vin.txid] = [vin.vout];
+                                    }
+                        //get utxos list
+                        this.promisedAPI(`api/addr/${senderAddr}/utxo`).then(utxos => {
+                            //form/construct the transaction data
+                            var trx = bitjs.transaction();
+                            var utxoAmt = 0.0;
+                            var fee = floGlobals.fee;
+                            for (var i = utxos.length - 1;
+                                (i >= 0) && (utxoAmt < sendAmt + fee); i--) {
+                                //use only utxos with confirmations (strict_utxo mode)
+                                if (utxos[i].confirmations || !strict_utxo) {
+                                    if (utxos[i].txid in unconfirmedSpent && unconfirmedSpent[utxos[i].txid].includes(utxos[i].vout))
+                                        continue; //A transaction has already used this utxo, but is unconfirmed.
+                                    trx.addinput(utxos[i].txid, utxos[i].vout, utxos[i].scriptPubKey);
+                                    utxoAmt += utxos[i].amount;
+                                };
+                            }
+                            if (utxoAmt < sendAmt + fee)
+                                reject("Insufficient FLO balance!");
+                            else {
+                                trx.addoutput(receiverAddr, sendAmt);
+                                var change = utxoAmt - sendAmt - fee;
+                                if (change > 0)
+                                    trx.addoutput(senderAddr, change);
+                                trx.addflodata(floData.replace(/\n/g, ' '));
+                                var signedTxHash = trx.sign(privKey, 1);
+                                this.broadcastTx(signedTxHash)
+                                    .then(txid => resolve(txid))
+                                    .catch(error => reject(error))
+                            }
+                        }).catch(error => reject(error))
                     }).catch(error => reject(error))
-                }
+                }).catch(error => reject(error))
             });
         },
 
@@ -7425,8 +7443,7 @@ Bitcoin.Util = {
                 this.promisedAPI(`api/addr/${floID}/utxo`).then(utxos => {
                     for (var i = utxos.length - 1; i >= 0; i--) {
                         if (utxos[i].confirmations) {
-                            trx.addinput(utxos[i].txid, utxos[i].vout, utxos[i]
-                                .scriptPubKey)
+                            trx.addinput(utxos[i].txid, utxos[i].vout, utxos[i].scriptPubKey)
                             utxoAmt += utxos[i].amount;
                         }
                     }
@@ -7611,8 +7628,7 @@ Bitcoin.Util = {
                             for (let i = utxos.length - 1;
                                 (i >= 0) && (utxoAmt < sendAmt); i--) {
                                 if (utxos[i].confirmations) {
-                                    trx.addinput(utxos[i].txid, utxos[i].vout, utxos[i]
-                                        .scriptPubKey)
+                                    trx.addinput(utxos[i].txid, utxos[i].vout, utxos[i].scriptPubKey)
                                     wifSeq.push(wif);
                                     utxoAmt += utxos[i].amount;
                                 }