Updating the child-count Functions sample.

Change-Id: Idc7a3b8732b0aae201271715498d5e73efe35579

Author: Nicolas Garnier

child-count/README.md

@@ -1,22 +1,22 @@
 # Tracking the number of elements in a list
 
-This template shows how to keep track of the number of elements in a Firebase Database list. This can be useful to keep tack of the number of "likes" or "followers" of a somethings shares through social media.
+This template shows how to keep track of the number of elements in a Firebase Database list. For instance this can be useful to keep tack of the number of "likes" or "followers" of something shared on a social platform.
 
-## Cloud Function Code
+## Functions Code
 
-See file [index.js](index.js) for the code.
+See file [index.js](functions/index.js) for the code.
 
 This is done by simply updating a `likes_count` attribute on the parent of the list node which is tracked.
 
 The dependencies are listed in [package.json](package.json).
 
 ## Sample Database Structure
 
-As an example we'll be using the database structure shown below. It keeps tracks of the list of users who liked an image and the count of these likes:
+As an example we'll be using the database structure shown below. It keeps tracks of the list of users who liked a post and the count of these likes:
 
 ```
 /functions-project-12345
-    /images
+    /posts
         /key-123456
             likes_count: 32
             /likes 
@@ -25,22 +25,3 @@ As an example we'll be using the database structure shown below. It keeps tracks
                 user786245: true
                 ...
 ```
-
-## Trigger rules
-
-Below is the trigger rule for the `countlikes` function making sure it's triggered when a new like is added/removed.
-
-```
-  "functions": {
-    ".source": "functions",
-    "countlikes": {
-      "triggers": {
-        "database": {
-          "path": "/images/$image/likes",
-        }
-      }
-    }
-  }
-```
-
-

child-count/index.js child-count/functions/index.jschild-count/index.js renamed to child-count/functions/index.js

@@ -1,5 +1,5 @@
 /**
- * Copyright 2015 Google Inc. All Rights Reserved.
+ * Copyright 2016 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.
@@ -15,17 +15,9 @@
  */
 'use strict';
 
-var Firebase = require('firebase');
-var env = require('./env');
-var ref = new Firebase(env.get('firebase.database.url'), 'admin');
-ref.auth(env.get('firebase.database.token'));
+var functions = require('firebase-functions');
 
 // Keeps track of the length of the 'likes' child list in a separate attribute.
-exports.countlikes = function(context, data) {
-  var nodeRef = ref.child(data.path);
-  console.log('Authenticated successfully with admin rights');
-  nodeRef.once('value').then(function(likesData) {
-    nodeRef.parent().child('likes_count').set(likesData.numChildren())
-        .then(context.done).catch(context.done);
-  }).catch(context.done);
-};
+exports.countlikes = functions.database().path('/posts/$postid/likes').on('value', event => {
+  return event.adminRef.parent().child('likes_count').set(event.data.numChildren());
+});

child-count/functions/package.json

@@ -0,0 +1,7 @@
+{
+  "main": "index.js",
+  "dependencies": {
+    "firebase": "^3.3.0",
+    "firebase-functions": "https://storage.googleapis.com/firebase-preview-drop/node/firebase-functions/firebase-functions-preview.latest.tar.gz"
+  }
+}