1 files changed, 34 insertions, 0 deletions
diff --git a/packages/testnet-faucets/src/ts/parameter_extractor.ts b/packages/testnet-faucets/src/ts/parameter_extractor.ts
new file mode 100644
index 000000000..f3a26ae01
--- /dev/null
+++ b/packages/testnet-faucets/src/ts/parameter_extractor.ts
@@ -0,0 +1,34 @@
+import { addressUtils } from '@0xproject/utils';
+import { NextFunction, Request, Response } from 'express';
+import * as _ from 'lodash';
+
+import { configs } from './configs';
+import { rpcUrls } from './rpc_urls';
+import { utils } from './utils';
+
+const DEFAULT_NETWORK_ID = 42; // kovan
+
+export const parameterExtractor = {
+    extract(req: Request, res: Response, next: NextFunction) {
+        const recipientAddress = req.params.recipient;
+        if (_.isUndefined(recipientAddress) || !_isValidEthereumAddress(recipientAddress)) {
+            res.status(400).send('INVALID_RECIPIENT_ADDRESS');
+            return;
+        }
+        const lowerCaseRecipientAddress = recipientAddress.toLowerCase();
+        req.recipientAddress = lowerCaseRecipientAddress;
+        const networkId = _.get(req.query, 'networkId', DEFAULT_NETWORK_ID);
+        const rpcUrl = _.get(rpcUrls, networkId);
+        if (_.isUndefined(rpcUrl)) {
+            res.status(400).send('UNSUPPORTED_NETWORK_ID');
+            return;
+        }
+        req.networkId = networkId;
+        next();
+    },
+};
+
+function _isValidEthereumAddress(address: string): boolean {
+    const lowercaseAddress = address.toLowerCase();
+    return addressUtils.isAddress(lowercaseAddress);
+}