Get dimension of an image object uploaded to firebase storage

getImageDimensions.js

const functions = require('firebase-functions');
const mkdirp = require('mkdirp-promise');
const admin = require('firebase-admin');
const { execFile } = require('child-process-promise');
const path = require('path');
const os = require('os');
const fs = require('fs');

admin.initializeApp();

exports.getImageDimensions = functions.storage
  .object()
  .onFinalize(async object => {
    // File and directory paths.
    const { name: filePath, contentType } = object;
    console.log(object);
    const tempLocalFile = path.join(os.tmpdir(), filePath);
    const tempLocalDir = path.dirname(tempLocalFile);

    // Exit if this is triggered on a file that is not an image.
    if (!contentType.startsWith('image/')) {
      return console.log('This is not an image.');
    }

    // Cloud Storage files.
    const bucket = admin.storage().bucket(object.bucket);
    const file = bucket.file(filePath);

    // Create the temp directory where the storage file will be downloaded.
    await mkdirp(tempLocalDir);
    // Download file from bucket.
    await file.download({ destination: tempLocalFile });

    console.log('The file has been downloaded to', tempLocalFile);
    // Get Dimensions of the image
    const { stdout } = await execFile(
      'identify',
      ['-format', '%wx%h', tempLocalFile],
      {
        capture: ['stdout', 'stderr'],
      }
    );

    const [height, width] = stdout.split('x');

    console.log(`Height:${height}Width:${width}`);

    fs.unlinkSync(tempLocalFile);

    return console.log('Done');
  });