Implement an API for faucet requests

.gitignore

@@ -128,3 +128,5 @@ dist
 .yarn/build-state.yml
 .yarn/install-state.gz
 .pnp.*
+
+db

package.json

@@ -8,7 +8,8 @@
   "private": true,
   "devDependencies": {
     "@types/express": "^4.17.21",
-    "typescript": "^5.5.3",
+    "@typescript-eslint/eslint-plugin": "^5.47.1",
+    "@typescript-eslint/parser": "^5.47.1",
     "eslint": "^8.35.0",
     "eslint-config-semistandard": "^15.0.1",
     "eslint-config-standard": "^16.0.3",
@@ -16,10 +17,13 @@
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-promise": "^5.1.0",
     "eslint-plugin-standard": "^5.0.0",
-    "@typescript-eslint/eslint-plugin": "^5.47.1",
-    "@typescript-eslint/parser": "^5.47.1"
+    "ts-node": "^10.9.2",
+    "typescript": "^5.5.3"
   },
   "dependencies": {
+    "@cosmjs/proto-signing": "^0.32.4",
+    "@cosmjs/stargate": "^0.32.4",
+    "@keyv/sqlite": "^3.6.7",
     "express": "^4.19.2"
   },
   "scripts": {

src/index.ts

@@ -1,11 +1,85 @@
 import express from 'express';
+import Keyv from 'keyv';
+
+import { DirectSecp256k1Wallet } from '@cosmjs/proto-signing';
+import { GasPrice, SigningStargateClient } from '@cosmjs/stargate';
+import KeyvSqlite from '@keyv/sqlite';
+
+// TODO: Take from a config file
+const config = {
+  rpcEndpoint: 'https://rpc.example.com',
+  faucetKey: 'your faucet key here',
+  chainId: 'laconic_9000-1',
+  denom: 'photon',
+  amount: '1000000',
+  prefix: 'laconic',
+  dailyLimit: '3000000',
+  dbPath: './db/faucet_data.sqlite'
+};
+
+// Initialize KV store with SQLite backend
+const keyv = new Keyv({
+  store: new KeyvSqlite({
+    uri: `sqlite://${config.dbPath}`,
+    table: 'keyv'
+  })
+});
+
 const app = express();
-const port = 3000;
+app.use(express.json());
 
-app.get('/', (req, res) => {
-  res.send('Hello World!');
+async function sendTokens (recipientAddress: string, amount: string): Promise<string> {
+  const wallet = await DirectSecp256k1Wallet.fromKey(
+    Buffer.from(config.faucetKey, 'hex'),
+    config.prefix
+  );
+  const [faucetAccount] = await wallet.getAccounts();
+  const client = await SigningStargateClient.connectWithSigner(config.rpcEndpoint, wallet, { gasPrice: GasPrice.fromString(`0.01${config.denom}`) });
+
+  const result = await client.sendTokens(
+    faucetAccount.address,
+    recipientAddress,
+    [{ denom: config.denom, amount: amount }],
+    'auto',
+    'Faucet transfer'
+  );
+
+  return result.transactionHash;
+}
+
+app.post('/faucet', async (req, res) => {
+  const { address } = req.body;
+
+  if (!address) {
+    return res.status(400).json({ error: 'Address is required' });
+  }
+
+  // Check rate limit
+  const now = Date.now();
+  const today = new Date(now).toISOString().split('T')[0];
+  const key = `${address}:${today}`;
+  const currentAmount = await keyv.get(key) || '0';
+
+  if (BigInt(currentAmount) + BigInt(config.amount) > BigInt(config.dailyLimit)) {
+    return res.status(429).json({ error: 'Limit exceeded' });
+  }
+
+  try {
+    const txHash = await sendTokens(address, config.amount);
+
+    console.log(`Sent tokens to address ${address}`);
+
+    // Update rate limit
+    await keyv.set(key, (BigInt(currentAmount) + BigInt(config.amount)).toString(), 86400000); // 24 hours TTL
+
+    res.json({ success: true, txHash });
+  } catch (error) {
+    console.error('Error sending tokens:', error);
+    res.status(500).json({ error: 'Failed to send tokens' });
+  }
 });
 
-app.listen(port, () => {
-  return console.log(`Express is listening at http://localhost:${port}`);
+const PORT = process.env.PORT || 3000;
+app.listen(PORT, () => {
+  console.log(`Faucet server running on port ${PORT}`);
 });