Adding a convert image sample

Change-Id: Id55a5a77180f4424242b2a02203fa45f6d5d7c3f

README.md

@@ -24,6 +24,12 @@ Demonstrates how to authorize with a 3rd party sign-in mechanism (Instagram in t
 
 Uses an HTTP trigger.
 
+### [Automatically Convert Images](/convert-images)
+
+Demonstrates how to automatically convert images that are uploaded to Firebase Storage to JPEG using ImageMagick.
+
+Uses a Firebase Storage trigger.
+
 ### [Text Moderation](/text-moderation)
 
 How to moderate user input text for bad words. For example this can be used to moderate usernames, chat or forum messages.

convert-images/README.md

@@ -0,0 +1,32 @@
+# Automatically Convert Images
+
+This sample demonstrates how to automatically convert images that are uploaded to Firebase Storage to JPEG using ImageMagick.
+
+
+## Functions Code
+
+See file [functions/index.js](functions/index.js) for the email sending code.
+
+The image conversion is performed using ImagMagick which is installed by default on all Firebase Functions. This is a CLI for which we use a NodeJS wrapper. The image is first downloaded locally from the Firebase Storage bucket to the `tmp` folder using the [google-cloud](https://github.com/GoogleCloudPlatform/google-cloud-node) SDK.
+
+The dependencies are listed in [functions/package.json](functions/package.json).
+
+
+## Trigger rules
+
+The function triggers on upload of any file to the Firebase Functions bucket.
+
+
+## Setting up the sample
+
+Create a Firebase project on the [Firebase Console](https://console.firebase.google.com) and visit the **Storage** tab.
+
+Replace the placeholder `FIREBASE_STORAGE_BUCKET_NAME` with the name of the Firebase Storage bucket which can be found in the **Storage** tab of your Firebase project's console. It is typically of the form `<project-id>.appspot.com`.
+
+
+## Deploy and test
+
+To test the sample:
+
+ - Deploy your project using `firebase deploy`
+ - Go to the Firebase Console **Storage** tab and upload an image that is not a JEPG, for instance a PNG. After a short time an image with the same base name but the `.jpg` extension will be created in the same folder (make sure you refresh the UI to see the new file).

convert-images/firebase.json

@@ -0,0 +1 @@
+{}

convert-images/functions/index.js

@@ -0,0 +1,99 @@
+/**
+ * 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.
+ * 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 t`he specific language governing permissions and
+ * limitations under the License.
+ */
+'use strict';
+
+const functions = require('firebase-functions');
+const im = require('imagemagick');
+const mkdirp = require('mkdirp');
+const gcs = require('@google-cloud/storage')();
+const Q = require('q');
+
+// File extension for the created JPEG files.
+const JPEG_EXTENSION = 'jpg';
+
+/**
+ * When an image is uploaded in the Storage bucket it is converted to JPEG automatically using
+ * ImageMagick.
+ */
+// TODO(DEVELOPER): Replace the placeholder below with the name of the Firebase Functions bucket.
+exports.imagetojpg = functions.cloud.storage(FIREBASE_STORAGE_BUCKET_NAME).onChange(event => {
+  console.log(event);
+  const result = Q.defer();
+
+  const filePath = event.data.name;
+  const filePathSplit = filePath.split('/');
+  const fileName = filePathSplit.pop();
+  const fileNameSplit = fileName.split('.');
+  const fileExtension = fileNameSplit.pop();
+  const baseFileName = fileNameSplit.join('.');
+  const fileDir = filePathSplit.join('/') + (filePathSplit.length > 0 ? '/' : '');
+  const JPEGFilePath = `${fileDir}${baseFileName}.${JPEG_EXTENSION}`;
+  const tempLocalDir = `/tmp/${fileDir}`;
+  const tempLocalFile = `${tempLocalDir}${fileName}`;
+  const tempLocalJPEGFile = `/tmp/${JPEGFilePath}`;
+
+  // Exit if this is triggered on a file that is not an image.
+  if (!event.data.contentType.startsWith('image/')) {
+    console.log('This is not an image.');
+    return null;
+  }
+
+  // Exit if this is triggered on a file that is not an image.
+  if (event.data.contentType.startsWith('image/jpeg')) {
+    console.log('Already a JPEG.');
+    return null;
+  }
+
+  // Exit if this is a move or deletion event.
+  if (event.data.resourceState === 'not_exists') {
+    console.log('This is a deletion event.');
+    return null;
+  }
+
+  // Create the temp directory where the storage file will be downloaded.
+  mkdirp(tempLocalDir, err => {
+    if (err) return result.reject(err);
+
+    // Download file from bucket.
+    const bucket = gcs.bucket(event.data.bucket);
+    bucket.file(filePath).download({
+      destination: tempLocalFile
+    }, err => {
+      if (err) return result.reject(err);
+
+      console.log('The file has been downloaded to', tempLocalFile);
+      // Convert the image to JPEG using ImageMagick.
+      im.convert([
+        tempLocalFile,
+        tempLocalJPEGFile
+      ], err => {
+        if (err) return result.reject(err);
+
+        console.log('Created JPEG for', filePath);
+        // Uploading the JPEG.
+        bucket.upload(tempLocalJPEGFile, {
+          destination: JPEGFilePath
+        }, err => {
+          if (err) return result.reject(err);
+
+          console.log('JPEG uploaded to Storage at', JPEGFilePath);
+          result.resolve();
+        });
+      });
+    });
+  });
+  return result.promise;
+});

convert-images/functions/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "functions",
+  "description": "Firebase Functions",
+  "dependencies": {
+    "@google-cloud/storage": "^0.2.0",
+    "firebase": "^3.4.1",
+    "firebase-functions": "https://storage.googleapis.com/firebase-preview-drop/node/firebase-functions/firebase-functions-preview.latest.tar.gz",
+    "imagemagick": "^0.1.3",
+    "mkdirp": "^0.5.1",
+    "q": "^1.4.1"
+  }
+}