Update the limit-children Functions sample.

Change-Id: I7e80739735fb33c479d19bfd471c87b3e07eb3ba

limit-children/README.md

@@ -2,11 +2,11 @@
 
 This template shows how to keep the number of child nodes in a Firebase database below a given number. This can be used to limit the number of lines of a chat history or logs.
 
-## Cloud Function Code
+## Functions Code
 
-See file [index.js](index.js) for the code.
+See file [index.js](function/index.js) for the code.
 
-The dependencies are listed in [package.json](package.json).
+The dependencies are listed in [package.json](function/package.json).
 
 ## Sample Database Structure
 
@@ -23,21 +23,4 @@ As an example we'll be using a simple chat database structure:
             text: "Hey Mat! What's Up?"
 ```
 
-## Trigger rules
-
-Below is the trigger rule for the `truncate` function making sure it's triggered when a new chat message is added.
-
-```
-  "functions": {
-    ".source": "functions",
-    "truncate": {
-      "triggers": {
-        "database": {
-          "path": "/chat/$messageid"
-        }
-      }
-    }
-  }
-```
-
-
+Every time a new chat message is added the Function runs. It counts the number of chat messages and removes the old ones if there are too many.

limit-children/index.js → limit-children/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.
@@ -15,35 +15,26 @@
  */
 'use strict';
 
-// Create an all access Firebase Database reference.
-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'));
+const functions = require('firebase-functions');
 
 // Max number of lines of the chat history.
-var MAX_LOG_COUNT = 5;
+const MAX_LOG_COUNT = 5;
 
-// Removes siblings of the node that element that triggered the function if there are more than MAX_LOG_COUNT
-function truncate(context, data) {
-  var parentRef = ref.child(data.path).parent();
-  parentRef.once('value').then(function(snapshot) {
+// Removes siblings of the node that element that triggered the function if there are more than MAX_LOG_COUNT.
+// In this example we'll keep the max number of chat message history to MAX_LOG_COUNT.
+exports.truncate = functions.database().path('/chat/$messageid').on('value', event => {
+  var parentRef = event.data.ref.parent();
+  return parentRef.once('value').then(snapshot => {
     if (snapshot.numChildren() > MAX_LOG_COUNT) {
       var childCount = 0;
       var updates = {};
       snapshot.forEach(function(child) {
         if (++childCount < snapshot.numChildren() - MAX_LOG_COUNT) {
-          updates[child.key()] = null;
+          updates[child.key] = null;
         }
       });
-      // Update the parent. This effectiovely removes the extra children.
-      parentRef.update(updates).then(context.done);
-    } else {
-      context.done();
+      // Update the parent. This effectively removes the extra children.
+      return parentRef.update(updates);
     }
-  }).catch(context.done);
-}
-
-module.exports = {
-  truncate: truncate
-};
+  });
+});

limit-children/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"
+  }
+}

limit-children/package.json

@@ -1,6 +0,0 @@
-{
-  "main": "index.js",
-  "dependencies": {
-    "firebase": "^2.4.0"
-  }
-}