functions-samples/Node-1st-gen/quickstarts/thumbnails/functions/index.js at main · firebase/functions-samples · GitHub

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/**
 * 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 the specific language governing permissions and
 * limitations under the License.
 */
'use strict';

// [START import]
const functions = require('firebase-functions/v1');
const admin = require('firebase-admin');
admin.initializeApp()
const path = require('path');

//library for resizing images
const sharp = require('sharp');
// [END import]

// [START generateThumbnail]
/**
 * When an image is uploaded in the Storage bucket,
 * generate a thumbnail automatically using sharp.
 */
// [START generateThumbnailTrigger]
exports.firstGenGenerateThumbnail = functions.storage.object().onFinalize(async (object) => {
// [END generateThumbnailTrigger]
  // [START eventAttributes]
  const fileBucket = object.bucket; // The Storage bucket that contains the file.
  const filePath = object.name; // File path in the bucket.
  const contentType = object.contentType; // File content type.
  // [END eventAttributes]

  // [START stopConditions]
  // Exit if this is triggered on a file that is not an image.
  if (!contentType.startsWith('image/')) {
    return functions.logger.log('This is not an image.');
  }

  // Get the file name.
  const fileName = path.basename(filePath);
  // Exit if the image is already a thumbnail.
  if (fileName.startsWith('thumb_')) {
    return functions.logger.log('Already a Thumbnail.');
  }
  // [END stopConditions]

  // [START thumbnailGeneration]
  // Download file from bucket.
  const bucket = admin.storage().bucket(fileBucket);
  const metadata = {
    contentType: contentType,
  };
  const downloadResponse = await bucket.file(filePath).download();
  const imageBuffer = downloadResponse[0];
  functions.logger.log("Image downloaded!");

  // Generate a thumbnail using sharp.
  const thumbnailBuffer = await sharp(imageBuffer).resize({
    width: 200,
    height: 200,
    withoutEnlargement: true,
  }).toBuffer();
  functions.logger.log("Thumbnail created");

  // Upload the thumbnail with a 'thumb_' prefix.
  const thumbFileName = `thumb_${fileName}`;
  const thumbFilePath = path.join(path.dirname(filePath), thumbFileName);
  await bucket.file(thumbFilePath).save(thumbnailBuffer, {
    metadata: metadata,
  });
  return functions.logger.log("Thumbnail uploaded!");
  // [END thumbnailGeneration]
});
// [END generateThumbnail]