2 files changed, 32 insertions, 1 deletions

diff --git a/src/app.js b/src/app.js
index 8c863a2..9067aa6 100644
--- a/src/app.js
+++ b/src/app.js
@@ -7,8 +7,10 @@ const app = express();
 app.use(bodyParser.urlencoded({ extended: false }));
 
 app.post('/sms', (req, res) => {
-  const 
+  /** @type {string} */
+  const body = req.body;
   const twiml = new MessagingResponse();
+  twiml.message(JSON.stringify(body));
   res.type('text/xml').send(twiml.toString());
 });
 
diff --git a/src/db.js b/src/db.js
new file mode 100644
index 0000000..145b144
--- /dev/null
+++ b/src/db.js
@@ -0,0 +1,29 @@
+// Ideally, we should write to a file and read it at app start in case of crashes.
+// An actual SQL database would probably be overkill.
+
+/** @type Array<{ name: string, number: string }> */
+const subscriptions = [];
+
+/**
+ * @param {string} number
+ * @param {string} name
+ */
+export function subscribe(number, name) {
+  subscriptions.push({ name, number });
+}
+
+/**
+ * @param {string} number
+ */
+export function isSubscribed(number) {
+  return subscriptions.some(s => s.number == number);
+}
+
+export function getSubscriptions() {
+  /** @type Array<{ name: string, number: string }> */
+  const clone = [];
+  for (const subscription of subscriptions) {
+    clone.push({ ...subscription });
+  }
+  return clone;
+}
\ No newline at end of file