Merge pull request #25 from rsksmart/feat/estimation-fee

Feat/estimation fee
rsksmart · Aug 22, 2024 · 1cb0f5e · 1cb0f5e
2 parents 70c344b + 892479d
commit 1cb0f5e
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Showing 5 changed files with 29 additions and 7 deletions.
diff --git a/dev-config.json b/dev-config.json
@@ -8,7 +8,7 @@
   "FAUCET_PRIVATE_KEY": "c3d40c98585e2c61add9c6a94b66cd7f5c5577e45d900c6c0e3139df1310292f",
   "GAS_PRICE": 60000000,
   "GAS_LIMIT": 100000,
-  "VALUE_TO_DISPENSE": 0.005,
+  "VALUE_TO_DISPENSE": 0.0005,
   "TAG_MANAGER_ID": "NO_ID",
   "FILTER_BY_IP": true,
   "TIMER_LIMIT": 180000

diff --git a/pages/api/dispense.ts b/pages/api/dispense.ts
@@ -11,7 +11,7 @@ import {
   DispenseResponse,
 } from '../../types/types';
 import { CronJob } from 'cron';
-import { filterByIP, provider } from '../../utils/env-util';
+import { filterByIP, provider, valueToDispense } from '../../utils/env-util';
 import {
   alreadyDispensed,
   captchaRejected,
@@ -96,8 +96,9 @@ const handleDispense = async (req: NextApiRequest, res: NextApiResponse): Promis
 
       res.status(409).end(JSON.stringify(data)); //409 Conflict
     } else {
+      const fee = await estimationFee(dispenseAddress);
       const txParametersGenerator = new TxParametersGenerator();
-      const txParameters: TxParameters = await txParametersGenerator.generate(dispenseAddress, web3);
+      const txParameters: TxParameters = await txParametersGenerator.generate(dispenseAddress, web3, fee);
 
       logger.txParameters(txParameters);
 
@@ -190,4 +191,19 @@ function filterAddresses(faucetHistory: FaucetHistory, dispenseAddress: string,
   return faucetHistory;
 }
 
+async function estimationFee(dispenseAddress:string) {
+  const VALUE_TO_DISPENSE = valueToDispense();
+  const value = web3.utils.toWei(VALUE_TO_DISPENSE.toString(), 'ether');
+  const gasEstimate = await web3.eth.estimateGas({
+    from: faucetAddress(),
+    to: dispenseAddress,
+    data: '',
+    value: value
+  });
+  const gasPrice = await web3.eth.getGasPrice();
+  const estimatedCost = web3.utils.toBN(gasEstimate).mul(web3.utils.toBN(gasPrice));
+  const fee = web3.utils.fromWei(estimatedCost, 'ether');
+  return Number(fee) || 0;
+}
+
 export default handleDispense;
diff --git a/prod-config.json b/prod-config.json
@@ -6,7 +6,7 @@
   "SITE_KEY_CAPTCHA": "",
   "GAS_PRICE": 60000000,
   "GAS_LIMIT": 100000,
-  "VALUE_TO_DISPENSE": 0.005,
+  "VALUE_TO_DISPENSE": 0.0005,
   "TAG_MANAGER_ID": "NO_ID",
   "FILTER_BY_IP": true,
   "TIMER_LIMIT": 180000

diff --git a/test-config.json b/test-config.json
@@ -8,7 +8,7 @@
   "FAUCET_PRIVATE_KEY": "c3d40c98585e2c61add9c6a94b66cd7f5c5577e45d900c6c0e3139df1310292f",
   "GAS_PRICE": 60000000,
   "GAS_LIMIT": 100000,
-  "VALUE_TO_DISPENSE": 0.005,
+  "VALUE_TO_DISPENSE": 0.0005,
   "FILTER_BY_IP": true,
   "TIMER_LIMIT": 180000
 }
diff --git a/utils/tx-parameters-generator.ts b/utils/tx-parameters-generator.ts
@@ -4,14 +4,20 @@ import { faucetAddress } from './faucet-sensitive-util';
 import Web3 from 'web3';
 
 class TxParametersGenerator {
-  async generate(dispenseAddress: string, web3: Web3) {
+  async generate(dispenseAddress: string, web3: Web3, fee: number) {
+    const VALUE_TO_DISPENSE = valueToDispense();
+
+    const valueInWei = web3.utils.toWei(VALUE_TO_DISPENSE.toString(), 'ether');
+    const feeInWei = web3.utils.toWei(fee.toString(), 'ether');
+    const valueToSend = web3.utils.toBN(valueInWei).sub(web3.utils.toBN(feeInWei));
+
     const txParameters: TxParameters = {
       from: faucetAddress(),
       to: dispenseAddress,
       nonce: web3.utils.toHex(await web3.eth.getTransactionCount(faucetAddress(), 'pending')),
       gasPrice: web3.utils.toHex(gasPrice()),
       gas: web3.utils.toHex(gasLimit()),
-      value: web3.utils.toHex(web3.utils.toWei(valueToDispense().toString()))
+      value: web3.utils.toHex(valueToSend)
     };
 
     return txParameters;