Add sepolia faucet

cmd/server.go

@@ -18,21 +18,22 @@ import (
 
 var (
 	appVersion = "v1.2.0"
-	chainIDMap = map[string]int{"sepolia": 11155111, "holesky": 17000, "opengradient": 10740}
+	chainIDMap = map[string]int{"sepolia": 11155111, "holesky": 17000, "opengradient": 10740, "base_sepolia": 84532}
 
 	httpPortFlag = flag.Int("httpport", 8090, "Listener port to serve HTTP connection")
 	proxyCntFlag = flag.Int("proxycount", 1, "Count of reverse proxies in front of the server")
 	versionFlag  = flag.Bool("version", false, "Print version number")
 
-	payoutFlag   = flag.Float64("faucet.amount", 0.03, "Number of Ethers to transfer per user request")
-	intervalFlag = flag.Int("faucet.minutes", 300, "Number of minutes to wait between funding rounds")
-	netnameFlag  = flag.String("faucet.name", "opengradient", "Network name to display on the frontend")
-	symbolFlag   = flag.String("faucet.symbol", "OGETH", "Token symbol to display on the frontend")
+	payoutFlag     = flag.Float64("faucet.amount", 0.1, "Number of tokens to transfer per user request")
+	intervalFlag   = flag.Int("faucet.minutes", 300, "Number of minutes to wait between funding rounds")
+	netnameFlag    = flag.String("faucet.name", "base_sepolia", "Network name to display on the frontend")
+	symbolFlag     = flag.String("faucet.symbol", "OPG", "Token symbol to display on the frontend")
+	tokenAddrFlag  = flag.String("faucet.tokenaddr", "0x240b09731D96979f50B2C649C9CE10FcF9C7987F", "ERC-20 token contract address to disperse (empty for native ETH)")
 
 	keyJSONFlag  = flag.String("wallet.keyjson", os.Getenv("KEYSTORE"), "Keystore file to fund user requests with")
 	keyPassFlag  = flag.String("wallet.keypass", "password.txt", "Passphrase text file to decrypt keystore")
 	privKeyFlag  = flag.String("wallet.privkey", os.Getenv("PRIVATE_KEY"), "Private key hex to fund user requests with")
-	providerFlag = flag.String("wallet.provider", "https://ogevmdevnet.opengradient.ai", "Endpoint for Ethereum JSON-RPC connection")
+	providerFlag = flag.String("wallet.provider", "https://sepolia.base.org", "Endpoint for Ethereum JSON-RPC connection")
 
 	hcaptchaSiteKeyFlag = flag.String("hcaptcha.sitekey", os.Getenv("HCAPTCHA_SITEKEY"), "hCaptcha sitekey")
 	hcaptchaSecretFlag  = flag.String("hcaptcha.secret", os.Getenv("HCAPTCHA_SECRET"), "hCaptcha secret")
@@ -56,7 +57,7 @@ func Execute() {
 		chainID = big.NewInt(int64(value))
 	}
 
-	txBuilder, err := chain.NewTxBuilder(*providerFlag, privateKey, chainID)
+	txBuilder, err := chain.NewTxBuilder(*providerFlag, privateKey, chainID, *tokenAddrFlag)
 	if err != nil {
 		panic(fmt.Errorf("cannot connect to web3 provider: %w", err))
 	}

internal/chain/transaction.go

@@ -27,9 +27,10 @@ type TxBuild struct {
 	fromAddress     common.Address
 	nonce           uint64
 	supportsEIP1559 bool
+	tokenAddress    *common.Address
 }
 
-func NewTxBuilder(provider string, privateKey *ecdsa.PrivateKey, chainID *big.Int) (TxBuilder, error) {
+func NewTxBuilder(provider string, privateKey *ecdsa.PrivateKey, chainID *big.Int, tokenAddr string) (TxBuilder, error) {
 	client, err := ethclient.Dial(provider)
 	if err != nil {
 		return nil, err
@@ -54,6 +55,12 @@ func NewTxBuilder(provider string, privateKey *ecdsa.PrivateKey, chainID *big.In
 		fromAddress:     crypto.PubkeyToAddress(privateKey.PublicKey),
 		supportsEIP1559: supportsEIP1559,
 	}
+
+	if tokenAddr != "" {
+		addr := common.HexToAddress(tokenAddr)
+		txBuilder.tokenAddress = &addr
+	}
+
 	txBuilder.refreshNonce(context.Background())
 
 	return txBuilder, nil
@@ -68,13 +75,24 @@ func (b *TxBuild) Transfer(ctx context.Context, to string, value *big.Int) (comm
 	toAddress := common.HexToAddress(to)
 	nonce := b.getAndIncrementNonce()
 
+	// Determine transaction target and data based on whether this is an ERC-20 transfer
+	txTo := &toAddress
+	txValue := value
+	var txData []byte
+
+	if b.tokenAddress != nil {
+		txTo = b.tokenAddress
+		txValue = big.NewInt(0)
+		txData = buildERC20TransferData(toAddress, value)
+	}
+
 	var err error
 	var unsignedTx *types.Transaction
 
 	if b.supportsEIP1559 {
-		unsignedTx, err = b.buildEIP1559Tx(ctx, &toAddress, value, gasLimit, nonce)
+		unsignedTx, err = b.buildEIP1559Tx(ctx, txTo, txValue, gasLimit, nonce, txData)
 	} else {
-		unsignedTx, err = b.buildLegacyTx(ctx, &toAddress, value, gasLimit, nonce)
+		unsignedTx, err = b.buildLegacyTx(ctx, txTo, txValue, gasLimit, nonce, txData)
 	}
 
 	if err != nil {
@@ -101,7 +119,21 @@ func (b *TxBuild) Transfer(ctx context.Context, to string, value *big.Int) (comm
 	return signedTx.Hash(), nil
 }
 
-func (b *TxBuild) buildEIP1559Tx(ctx context.Context, to *common.Address, value *big.Int, gasLimit uint64, nonce uint64) (*types.Transaction, error) {
+// buildERC20TransferData constructs calldata for ERC-20 transfer(address,uint256)
+func buildERC20TransferData(to common.Address, amount *big.Int) []byte {
+	// Function selector: keccak256("transfer(address,uint256)") = 0xa9059cbb
+	methodID := []byte{0xa9, 0x05, 0x9c, 0xbb}
+	paddedAddress := common.LeftPadBytes(to.Bytes(), 32)
+	paddedAmount := common.LeftPadBytes(amount.Bytes(), 32)
+
+	var data []byte
+	data = append(data, methodID...)
+	data = append(data, paddedAddress...)
+	data = append(data, paddedAmount...)
+	return data
+}
+
+func (b *TxBuild) buildEIP1559Tx(ctx context.Context, to *common.Address, value *big.Int, gasLimit uint64, nonce uint64, data []byte) (*types.Transaction, error) {
 	header, err := b.client.HeaderByNumber(ctx, nil)
 	if err != nil {
 		return nil, err
@@ -124,10 +156,11 @@ func (b *TxBuild) buildEIP1559Tx(ctx context.Context, to *common.Address, value
 		Gas:       gasLimit,
 		To:        to,
 		Value:     value,
+		Data:      data,
 	}), nil
 }
 
-func (b *TxBuild) buildLegacyTx(ctx context.Context, to *common.Address, value *big.Int, gasLimit uint64, nonce uint64) (*types.Transaction, error) {
+func (b *TxBuild) buildLegacyTx(ctx context.Context, to *common.Address, value *big.Int, gasLimit uint64, nonce uint64, data []byte) (*types.Transaction, error) {
 	gasPrice, err := b.client.SuggestGasPrice(ctx)
 	if err != nil {
 		return nil, err
@@ -142,6 +175,7 @@ func (b *TxBuild) buildLegacyTx(ctx context.Context, to *common.Address, value *
 		Gas:      gasLimit,
 		To:       to,
 		Value:    value,
+		Data:     data,
 	}), nil
 }
 

web/src/Faucet.svelte

@@ -33,7 +33,7 @@
     hcaptchaLoaded = true;
   };
 
-  $: document.title = "OpenGradient Devnet Faucet";
+  $: document.title = "$" + faucetInfo.symbol + " Faucet on " + capitalize(faucetInfo.network.replace('_', ' '));
 
   let widgetID;
   $: if (mounted && hcaptchaLoaded) {
@@ -107,8 +107,7 @@
   }
 
   function capitalize(str) {
-    const lower = str.toLowerCase();
-    return str.charAt(0).toUpperCase() + lower.slice(1);
+    return str.toLowerCase().split(' ').map(word => word.charAt(0).toUpperCase() + word.slice(1)).join(' ');
   }
 </script>
 
@@ -132,17 +131,17 @@
               <span class="icon">
                 <i class="fa fa-bath" />
               </span>
-              <span><b>OpenGradient Devnet Faucet</b></span>
+              <span><b>${faucetInfo.symbol} Faucet on {capitalize(faucetInfo.network.replace('_', ' '))}</b></span>
             </a>
           </div>
           <div id="navbarMenu" class="navbar-menu">
             <div class="navbar-end">
               <span class="navbar-item">
                 <a
                   class="button is-white is-outlined"
-                  href="https://opengradient.ai"
+                  href="https://base.org"
                 >
-                  <span>opengradient.ai</span>
+                  <span>Base Sepolia</span>
                 </a>
               </span>
             </div>