Adding the lastmodified sample

README.md

@@ -13,15 +13,11 @@ This repository contains the following templates:
 
 ### [Text Moderation](/text-moderation)
 
-How to moderate user input text for bad words.
+How to moderate user input text for bad words. For example this can be used to moderate usernames, chat or forum messages.
 
-### [Username Moderation](/username-moderation) TODO import from go/hearth-codesamples
+### [LastModified Firebase DB tracking](/lastmodified-tracking)
 
-How to moderate new user names for bad words.
-
-### [LastModified Firebase DB tracking](/lastmodified-tracking) TODO import from go/hearth-codesamples
-
-Tracking when the Firebase DB was last modified.
+Tracking when the Firebase DB (or a subset) was last modified.
 
 ### [Automatic message translation](/message-translation) TODO import from go/hearth-codesamples
 

lastmodified-tracking/README.md

@@ -0,0 +1,58 @@
+# Tracking last modified Date of a Firebase Database
+
+This template shows how to keep track of the date at which the Firebase Database or a subset of a firebase Database was last modified.
+
+## Cloud Function Code
+
+See file [index.js](index.js) for the code.
+
+This is done by simply updating a `lastmodified` attribute on the parent of the node which is tracked (for instance at the root of the Database).
+
+## Sample Database Structure
+
+As an example we'll be using a simple chat database structure:
+
+```
+/functions-project-12345
+    /chat
+        /key-123456
+            username: "Mat"
+            text: "Hey Bob!"
+        /key-123457
+            username: "Bob"
+            text: "Hey Mat"
+```
+
+## Trigger rules
+
+Below is the trigger rule for the `touch` function making sure it's triggered when a new chat message is added/modified.
+
+```
+  "functions": {
+    ".source": "functions",
+    "touch": {
+      "triggers": {
+        "database": {
+          "path": "/chat/$message",
+        }
+      }
+    }
+  }
+```
+
+## Security Rules
+
+The following security rules ensures only a Cloud Function with admin access can update the `lastmodified` attribute.
+
+```
+{
+  "rules": {
+    "lastmodified": {
+        ".write": "false", // TODO: Check taht this works with GCF admin access!
+        ".read": "true"
+    }
+  }
+}
+```
+
+

lastmodified-tracking/index.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright 2015 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+'use strict';
+
+var Firebase = require('firebase');
+var env = require('./env');
+var ref = new Firebase(env.get('firebase.database.url'));
+
+function touch(context, data) {
+  ref.auth(env.get('firebase.database.token'), function(error, result) {
+    if (error) {
+      context.done(error);
+    } else {
+      console.log('Authenticated successfully with admin rights');
+      ref.child('lastmodified').set(Firebase.ServerValue.TIMESTAMP);
+      context.done();
+    }
+  });
+}
+
+module.exports = {
+  touch: touch
+}