Added the minimal-webhook sample.

README.md

@@ -19,6 +19,10 @@ How to moderate user input text for bad words. For example this can be used to m
 
 Tracking when the Firebase DB (or a subset) was last modified.
 
+### [Webhook upon Database writes](/minimal-webhook)
+
+Writing to the Database triggers a request to a callback URL (a Webhook). The content of the modified Data is sent to the Webhook.
+
 ### [Automatic message translation](/message-translation) TODO import from go/hearth-codesamples
 
 Integrates the Google Translate API to perform automatic text translation across any number of languages. Language codes can be stored in Firebase for on the fly changes.

minimal-webhook/README.md

@@ -0,0 +1,41 @@
+# Webhook upon Database writes
+
+This template shows how a Database write can trigger a request to a hardcoded callback URL (a Webhook). The content of the modified Data is sent to the Webhook.
+
+## Cloud Function Code
+
+See file [index.js](index.js) for the code.
+
+This is done by sending a request to a given URL. As a sample we're using a Request Bin from [requestb.in](http://requestb.in) that will receive the Data so you can visualize it easily. make sure you create your own Request Bin and update the sample with it.
+
+## Sample Database Structure
+
+As an example we'll be using a database structure where adding or updating an element under `/hooks` will trigger the Webhook:
+
+```
+/functions-project-12345
+    /hooks
+        /key-123456
+            stuff: "Whatever"
+            more_stuff: "Cool"
+        /key-123457
+            things: "A car"
+            more_things: "A truck"
+```
+
+## Trigger rules
+
+Below is the trigger rule for the `webhook` function making sure it's triggered when a new object is added/modified to the `hooks` attribute.
+
+```
+  "functions": {
+    ".source": "functions",
+    "webhook": {
+      "triggers": {
+        "database": {
+          "path": "/hooks/$hookId",
+        }
+      }
+    }
+  }
+```

minimal-webhook/index.js

@@ -0,0 +1,47 @@
+/**
+ * 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';
+
+// Create reference to the database authorized as an admin.
+var Firebase = require('firebase');
+var env = require('./env');
+var ref = new Firebase(env.get('firebase.database.url'), 'admin');
+ref.authWithCustomToken(env.get('firebase.database.secret'));
+
+// Import the request URL.
+var request = require('request');
+
+// This is the URL that we will callback and send the content fo the updated data node.
+// As an example we're using a Request Bin from http://requestb.in
+// TODO: Make sure you create your own Request Bin and change this URL to try this sample.
+var WEBHOOK_URL = 'http://requestb.in/1mqw97l1';
+
+// Reads the content of the node that triggered the function and sends it to the registered Webhook
+// URL.
+exports.webhook = function(context, data) {
+  ref.child(data.path).once('value', function(snap) {
+    request({
+      url: WEBHOOK_URL,
+      method: 'POST',
+      json: true,
+      body: snap.val()
+    }, function(err, response) {
+      if (err) { context.done(err); }
+      else if (response.statusCode >= 400) { context.done('HTTP Error:', response.statusCode) }
+      console.log('SUCCESS! Posted', data.path);
+    });
+  });
+};

minimal-webhook/package.json

@@ -0,0 +1,7 @@
+{
+  "main": "index.js",
+  "dependencies": {
+    "firebase": "^2.4.0",
+    "request": "^2.67.0"
+  }
+}