Added Recaptcha V2

.env.example

@@ -23,4 +23,5 @@ KAIACHAIN_GITHUB_API_KEY=
 KAIROS_RPC_URL=https://public-en-kairos.node.kaia.io
 FAUCET_PRIVATE_KEY=
 FAUCET_PUBLIC_KEY=
-FAUCET_TRANSFER_VALUE=50
+FAUCET_TRANSFER_VALUE=50
+FAUCET_RECAPTCHA_SECRET=

app.js

@@ -45,10 +45,11 @@ app.get("/faucet/balance", async function (req, res) {
 app.post("/faucet/run", async function (req, res) {
   try {
     let address = req.query.address || "";
+    let _gReCaptchaToken = req.body.recaptcha || "";
     if(!address) {
       throw new Error("Address is required")
     }
-    let results = await faucetService.runFaucet(address);
+    let results = await faucetService.runFaucet(address, _gReCaptchaToken);
     return res.status(200).json({ success: true, data: results})
   } catch(err) {
     console.log(err.message);

services/faucetService.js

@@ -7,6 +7,22 @@ let service = {};
 const provider = new Web3.providers.HttpProvider(process.env.KAIROS_RPC_URL);
 const web3 = new KlaytnWeb3(provider);
 
+const validateRecaptchaV2 = async (_gReCaptchaToken) => {
+  let reCaptchaRes = await fetch("https://www.google.com/recaptcha/api/siteverify", {
+      method: "POST",
+      headers: {
+          "Content-Type": "application/x-www-form-urlencoded",
+      },
+      body: `secret=${process.env.FAUCET_RECAPTCHA_SECRET}&response=${_gReCaptchaToken}`,
+      })
+      .then((reCaptchaRes) => reCaptchaRes.json());
+
+  logger.info(reCaptchaRes);
+  if(!(reCaptchaRes && reCaptchaRes.success)) {
+      throw new Error("Invalid Recaptcha");
+  }
+}
+
 async function clearOldCache() {
   let entries = Object.entries(global.faucetCache);
   for (let i = 0; i < entries.length; i++) {
@@ -37,8 +53,10 @@ service.getBalance = async (_address) => {
   }
 };
 
-service.runFaucet = async (_address) => {
+service.runFaucet = async (_address, _gReCaptchaToken) => {
   try {
+    await validateRecaptchaV2(_gReCaptchaToken);
+
     let isAddress = web3.utils.isAddress(_address);
     if (isAddress) {
       _address = _address.toLowerCase();