Frontend - Firebase heartbeat validation and deploy function

frontend/firebase.json

@@ -54,5 +54,29 @@
         ]
       }
     ]
-  }
+  },
+  "emulators": {
+    "functions": {
+      "port": 5000
+    },
+    "firestore": {
+      "port": 8080
+    },
+    "ui": {
+      "enabled": true
+    }
+  },
+  "functions": [
+    {
+      "source": "functions",
+      "codebase": "default",
+      "ignore": [
+        "node_modules",
+        ".git",
+        "firebase-debug.log",
+        "firebase-debug.*.log",
+        "*.local"
+      ]
+    }
+  ]
 }

frontend/functions/.gitignore

@@ -0,0 +1,2 @@
+node_modules/
+*.local

frontend/functions/index.js

@@ -0,0 +1,81 @@
+/**
+ * Import function triggers from their respective submodules:
+ *
+ * const {onCall} = require("firebase-functions/v2/https");
+ * const {onDocumentWritten} = require("firebase-functions/v2/firestore");
+ *
+ * See a full list of supported triggers at https://firebase.google.com/docs/functions
+ */
+//
+// const {onRequest} = require('firebase-functions/v2/https');
+// const logger = require('firebase-functions/logger');
+//
+// Create and deploy your first functions
+// https://firebase.google.com/docs/functions/get-started
+//
+// exports.helloWorld = onRequest((request, response) => {
+//   logger.info('Hello logs!', {structuredData: true});
+//   response.send('Hello from Firebase!');
+// });
+
+const admin = require('firebase-admin');
+const functions = require('firebase-functions');
+
+admin.initializeApp();
+
+const allowedPublicKeys = new Set([
+  'publicKey1Base64Encoded',
+  'publicKey2Base64Encoded',
+  // Add more as needed
+]);
+
+function validateSignature(data, signature, publicKeyBase64) {
+
+  return true;
+}
+
+exports.handleValidationAndStore = functions.region('us-central1').https.onCall(async (data, context) => {
+  console.log('Received data:', data);
+  const {publicKey, data: inputData, signature} = data;
+
+  // Check if the publicKey is in the allowed set
+  if (!allowedPublicKeys.has(publicKey)) {
+    throw new functions.https.HttpsError('permission-denied', 'Public key not authorized');
+  }
+
+  // Rate limiting based on public key
+  const rateLimitRef = admin.firestore().collection('publicKeyRateLimits').doc(publicKey);
+
+  try {
+    await admin.firestore().runTransaction(async (transaction) => {
+      const doc = await transaction.get(rateLimitRef);
+      const now = Date.now();
+      const cutoff = now - 15 * 1000; // 15 seconds ago
+
+      if (doc.exists) {
+        const lastCall = doc.data().lastCall;
+        if (lastCall > cutoff) {
+          throw new functions.https.HttpsError('resource-exhausted', 'Rate limit exceeded for this public key');
+        }
+      }
+
+      transaction.set(rateLimitRef, {lastCall: now}, {merge: true});
+    });
+
+    // Validate signature
+    if (!validateSignature(inputData, signature, publicKey)) {
+      throw new functions.https.HttpsError('unauthenticated', 'Signature validation failed');
+    }
+
+    // Store data in 'heartbeat' collection
+    await admin.firestore().collection('heartbeat').add(inputData);
+
+    return {message: 'Data validated and stored successfully'};
+  } catch (error) {
+    console.error('Error during data validation and storage:', error);
+    if (error instanceof functions.https.HttpsError) {
+      throw error; // Re-throw HttpsError for Firebase Functions to handle
+    }
+    throw new functions.https.HttpsError('internal', 'An error occurred during validation or storage');
+  }
+});