node-exiftool

A Node.js interface to the exiftool command-line application.

Exiftool is an amazing tool written by Phil Harvey in Perl which can read and write metadata to a number of file formats. It is very powerful and allows to do such things as extracting orientation from JPEG files uploaded to your server by users to rotate generated previews accordingly, as well as appending copyright information to photos using IPTC standard.

This npm package has a preinstall script which will fetch exiftool's source from SourceForge with curl and extract it into the /vendor directory. This means you don't have to have exiftool preinstalled to use this software, however if you do, you can also specify a path to the executable as shown below.

Usage

The module spawns an exiftool process with -stay_open True -@ - arguments, so that there is no overhead related to starting a new process to read every file or directory. The package creates a process asynchronously and listens for stdout and stderr data events and uses promises thus avoiding blocking the Node's event loop.

Important: since version 2, exiftool is not distributed with node-exiftool. The module will try to spawn exiftool, therefore you must install it manually. You can also use dist-exiftool package which will install exiftool distribution appropriate for your platform.

Require

const exiftool = require('node-exiftool');
const ep = new exiftool.ExiftoolProcess();

Custom Executable

const exiftool = require('node-exiftool');
const ep = new exiftool.ExiftoolProcess('/usr/local/exiftool');

dist-exiftool

npm i --save dist-exiftool

const exiftool = require('node-exiftool');
const exiftoolBin = require('dist-exiftool');
const ep = new exiftool.ExiftoolProcess(exiftoolBin);

Single File

You are required to open the exiftool process first, after which you will be able to read and write metadata.

ep.open().then((pid) => {
    console.log('Started exiftool process %s', pid);
    return ep.readMetadata('photo.jpg').then((res) => {
        console.log(res);
    });
    // repeat as many times as required
}).then(() => {
    return ep.close().then(() => {
        console.log('Closed exiftool');
    });
});

{
  data: [
    {
      SourceFile: 'photo.jpg',
      ExifToolVersion: 10.16,
      FileName: 'photo.jpg',
      Directory: '.',
      FileSize: '51 kB',
      FileModifyDate: '2016:05:15 22:59:45+01:00',
      FileAccessDate: '2016:05:15 23:05:27+01:00',
      FileInodeChangeDate: '2016:05:15 22:59:45+01:00',
      FilePermissions: 'rw-r--r--',
      FileType: 'JPEG',
      FileTypeExtension: 'jpg',
      MIMEType: 'image/jpeg',
      XMPToolkit: 'Image::ExifTool 10.11',
      CreatorWorkURL: 'https://sobesednik.media',
      Scene: '011200',
      Creator: 'Anton',
      ImageWidth: 500,
      ImageHeight: 333,
      EncodingProcess: 'Baseline DCT, Huffman coding',
      BitsPerSample: 8,
      ColorComponents: 3,
      YCbCrSubSampling: 'YCbCr4:2:0 (2 2)',
      ImageSize: '500x333',
      Megapixels: 0.167
    }
  ],
  error: null
}

Directory

ep.readMetadata('DIR').then((res) => {
    console.log(res);
});

{
  data: [
    {
      SourceFile: 'DIR/IMG_9857.JPG',
      ExifToolVersion: 10.16,
      FileName: 'IMG_9857.JPG',
      Directory: 'DIR',
      FileSize: '51 kB',
      FileModifyDate: '2016:05:15 23:06:58+01:00',
      FileAccessDate: '2016:05:15 23:06:58+01:00',
      FileInodeChangeDate: '2016:05:15 23:06:58+01:00',
      FilePermissions: 'rw-r--r--',
      FileType: 'JPEG',
      FileTypeExtension: 'jpg',
      MIMEType: 'image/jpeg',
      XMPToolkit: 'Image::ExifTool 10.11',
      CreatorWorkURL: 'https://sobesednik.media',
      Scene: '011200',
      Creator: 'Anton',
      ImageWidth: 500,
      ImageHeight: 333,
      EncodingProcess: 'Baseline DCT, Huffman coding',
      BitsPerSample: 8,
      ColorComponents: 3,
      YCbCrSubSampling: 'YCbCr4:2:0 (2 2)',
      ImageSize: '500x333',
      Megapixels: 0.167
    },
    {
      SourceFile: 'DIR/IMG_9858.JPG',
      ExifToolVersion: 10.16,
      FileName: 'IMG_9858.JPG',
      Directory: 'DIR',
      FileSize: '52 kB',
      FileModifyDate: '2016:05:15 23:06:58+01:00',
      FileAccessDate: '2016:05:15 23:06:58+01:00',
      FileInodeChangeDate: '2016:05:15 23:06:58+01:00',
      FilePermissions: 'rw-r--r--',
      FileType: 'JPEG',
      FileTypeExtension: 'jpg',
      MIMEType: 'image/jpeg',
      ExifByteOrder: 'Big-endian (Motorola, MM)',
      Orientation: 'Rotate 90 CW',
      XResolution:72,
      YResolution:72,
      ResolutionUnit: 'inches',
      YCbCrPositioning: 'Centered',
      XMPToolkit: 'Image::ExifTool 10.11',
      CreatorWorkURL: 'https://sobesednik.media',
      Scene: '011200',
      Creator: 'Anton',
      ImageWidth: 500,
      ImageHeight: 334,
      EncodingProcess: 'Baseline DCT, Huffman coding',
      BitsPerSample: 8,
      ColorComponents: 3,
      YCbCrSubSampling: 'YCbCr4:2:0 (2 2)',
      ImageSize: '500x334',
      Megapixels: 0.167
    }
  ],
  error: '1 directories scanned\n    2 image files read'
}

File not found

ep.readMetadata('filenotfound.jpg').then((res) => {
    console.log(res);
});

{
  data: null,
  error: 'File not found: filenotfound.jpg'
}

Incorrect file format

ep.readMetadata('url.html').then((res) => {
    console.log(res);
});

{
  data: [
    {
      SourceFile: 'url.html',
      ExifToolVersion: 10.16,
      FileName: 'url.html',
      Directory: '.',
      FileSize: '574 bytes',
      FileModifyDate: '2016:05:15 23:28:30+01:00',
      FileAccessDate: '2016:05:15 23:28:30+01:00',
      FileInodeChangeDate: '2016:05:15 23:28:30+01:00',
      FilePermissions: 'rw-r-----',
      Error: 'File format error'
    }
  ],
  error: null
}

Custom Arguments

You can pass arguments which you wish to use in the exiftool command call. They will be automatically prepended with the - sign so you don't have to do it manually.

// include only some tags
ep.readMetadata('photo.jpg', ['Creator', 'CreatorWorkURL', 'Orientation'])
  .then((res) => {
      console.log(res);
  });

{
  data: [
    {
      SourceFile: 'photo.jpg',
      Creator: 'Anton',
      CreatorWorkURL: 'https://sobesednik.media',
      Orientation: 'Rotate 90 CW'
    }
  ],
  error: null
}

// exclude some tags and groups of tags
ep.readMetadata('photo.jpg', ['-ExifToolVersion', '-File:all']).then((res) => {
    console.log(res);
});

{
  data: [
    {
      SourceFile: 'photo.jpg',
      Orientation: 'Rotate 90 CW',
      XResolution: 72,
      YResolution: 72,
      ResolutionUnit: 'inches',
      YCbCrPositioning: 'Centered',
      XMPToolkit: 'Image::ExifTool 10.11',
      CreatorWorkURL: 'https://sobesednik.media',
      Scene: '011200',
      Creator: 'Anton',
      ImageSize: '500x334',
      Megapixels: 0.167
    }
  ],
  error: null
}

Events

You can also listen for OPEN and EXIT events. For example, if the exiftool process crashed, you might want to restart it.

const exiftool = require('./node-exiftool');
const ep = new exiftool.ExiftoolProcess();
const cp = require('child_process');

ep.on(exiftool.events.OPEN, (pid) => {
    console.log('Started exiftool process %s', pid);
});
ep.on(exiftool.events.EXIT, () => {
    console.log('exiftool process exited');
    ep.open();
});

ep.open().then(() => {
    cp.execSync('pkill -f exiftool');
});

Started exiftool process 95230
exiftool process exited
Started exiftool process 95232

Metadata

Metadata is awesome and although it can increase the file size, it preserves copyright and allows to find out additional information and the author of an image/movie. Let's all use metadata.

Resources

Exiftool Documentation