add missing examples

Author: brendanjryan

.gitignore

@@ -18,8 +18,8 @@ go.work
 # Build artifacts
 server
 server.exe
-simple-send
-feepayer
+/simple-send
+/feepayer
 bin/
 
 # Profiling files

examples/feepayer/README.md

@@ -0,0 +1,36 @@
+# Fee Payer
+
+## Overview
+
+Example fee payer relay server that enables gasless transactions on Tempo.
+
+The server accepts user-signed Type 0x76 transactions, adds its own fee payer signature, and broadcasts the dual-signed transaction to the network. 
+
+## Running
+
+1. Copy the environment file and configure your settings:
+
+```bash
+cd examples/feepayer
+cp env.example .env
+```
+
+2. Edit `.env` with your values:
+
+```env
+FEE_PAYER_PORT=3000
+TEMPO_RPC_URL=https://rpc.testnet.tempo.xyz
+TEMPO_USERNAME=your-username
+TEMPO_PASSWORD=your-password
+TEMPO_FEE_PAYER_PRIVATE_KEY=0x...
+ALPHAUSD_ADDRESS=0x20c0000000000000000000000000000000000001
+TEMPO_CHAIN_ID=42424
+```
+
+3. Run the server:
+
+```bash
+go run cmd/main.go
+```
+
+The server exposes `eth_sendRawTransaction` and `eth_sendRawTransactionSync` JSON-RPC methods on the configured port.

examples/feepayer/client/client.ts

@@ -0,0 +1,52 @@
+import { createClient, http, walletActions, publicActions } from 'viem';
+import { privateKeyToAccount } from 'viem/accounts';
+import { tempo } from 'tempo.ts/chains';
+import { withFeePayer } from 'tempo.ts/viem';
+import { config } from './config.js';
+
+async function main() {
+  console.log('Tempo Fee Payer Client Example');
+
+  const account = privateKeyToAccount(config.clientPrivateKey);
+  console.log('Client address:', account.address);
+
+  const client = createClient({
+    account,
+    chain: tempo({ feeToken: config.alphaUsdAddress }),
+    transport: withFeePayer(
+      http(config.getCleanRpcUrl(), {
+        fetchOptions: {
+          headers: {
+            Authorization: config.getAuthHeader(),
+          },
+        },
+      }),
+      http(config.feePayerServerUrl)
+    ),
+  })
+    .extend(publicActions)
+    .extend(walletActions);
+
+  console.log('Sending transaction via fee payer relay...');
+
+  const hash = await client.sendTransaction({
+    to: '0x0000000000000000000000000000000000000000',
+    data: '0xdeadbeef',
+    value: 0n,
+    feeToken: config.alphaUsdAddress,
+    feePayer: true,
+  } as any);
+
+  console.log('Transaction hash:', hash);
+  console.log('Waiting for confirmation...');
+
+  await client.waitForTransactionReceipt({ hash });
+
+  const transaction = await client.getTransaction({ hash });
+  console.log('Transaction confirmed!');
+  if (transaction.feePayer) {
+    console.log('Fee payer address:', transaction.feePayer);
+  }
+}
+
+main().catch(console.error);

examples/feepayer/client/config.ts

@@ -0,0 +1,47 @@
+import 'dotenv/config';
+
+export class Config {
+  readonly tempoRpcUrl: string;
+  readonly tempoUsername: string;
+  readonly tempoPassword: string;
+  readonly feePayerServerUrl: string;
+  readonly clientPrivateKey: `0x${string}`;
+  readonly alphaUsdAddress: `0x${string}`;
+
+  constructor() {
+    this.tempoRpcUrl = process.env.TEMPO_RPC_URL || 'https://rpc.testnet.tempo.xyz';
+    this.tempoUsername = process.env.TEMPO_USERNAME || '';
+    this.tempoPassword = process.env.TEMPO_PASSWORD || '';
+    this.feePayerServerUrl = process.env.FEE_PAYER_SERVER_URL || 'http://localhost:3000';
+    
+    const privateKey = process.env.TEMPO_CLIENT_PRIVATE_KEY;
+    if (!privateKey) {
+      throw new Error('TEMPO_CLIENT_PRIVATE_KEY environment variable is required');
+    }
+    this.clientPrivateKey = privateKey as `0x${string}`;
+    this.alphaUsdAddress = '0x20c0000000000000000000000000000000000001' as `0x${string}`;
+  }
+
+  /**
+   * Returns the RPC URL with credentials removed (for use in transport)
+   */
+  getCleanRpcUrl(): string {
+    return this.tempoRpcUrl.replace(/https?:\/\/[^@]+@/, 'https://');
+  }
+
+  /**
+   * Returns the Basic Auth credentials string (username:password)
+   */
+  getCredentials(): string {
+    return `${this.tempoUsername}:${this.tempoPassword}`;
+  }
+
+  /**
+   * Returns the Base64 encoded Basic Auth header value
+   */
+  getAuthHeader(): string {
+    return `Basic ${btoa(this.getCredentials())}`;
+  }
+}
+
+export const config = new Config();

examples/feepayer/client/env.example

@@ -0,0 +1,10 @@
+# Tempo RPC Configuration
+TEMPO_RPC_URL=https://rpc.testnet.tempo.xyz
+TEMPO_USERNAME=your-username
+TEMPO_PASSWORD=your-password
+
+# Client Private Key 
+TEMPO_CLIENT_PRIVATE_KEY=0x...
+
+# Fee Payer Server URL
+FEE_PAYER_SERVER_URL=http://localhost:3000