exifreader

ExifReader

ExifReader is a JavaScript library that parses image files and extracts the metadata. It can be used either in a browser or from Node. Supports JPEG, TIFF, and HEIC files with tags encoded using Exif, IPTC, and XMP (the latter two only for JPEG).

ExifReader supports module formats AMD, CommonJS and globals and can therefore easily be used from Webpack, RequireJS, Browserify, Node etc. Since it is written using ES2015+, you can also import the ES module directly from your own ES2015+ project.

Notes for exif-js users

If you come here from the popular but now dead exif-js package, please let me know if you're missing anything from it and I will try to help you. Some notes:

• Questions, bug reports, suggestions, and pull requests are very much welcome. If you've been using another Exif package you probably have some good insights on what's missing in this one.
• ExifReader has a different API, hopefully better. :-)
• XMP support in exif-js does not seem perfect. ExifReader should be a bit better on that part.
• ExifReader works with strict mode.
• exif-js accepts IMG HTML elements as input. This falls outside of the functionality of ExifReader. If you need this I suggest looking at exif-js source code to see how it's done for your specific case and then pass in the resulting data into ExifReader. If many people need this I could add a more explicit example for how to do it together with ExifReader.
• I've been maintaining this package since 2012 and I have no plans to stop doing that anytime soon.

Installation

Easiest is through npm or Bower:

npm install exifreader --save

bower install exifreader --save

If you want to clone the git repository instead:

git clone [e-mail]:mattiasw/ExifReader.git
cd ExifReader
npm install

After that, the transpiled, concatenated and minified ES5 file will be in the dist folder together with a sourcemap file.

Type definitions

Type definitions for TypeScript are included in the package. If you're missing any definitions for tags or something else, a pull-request would be very much welcome since I'm not using TypeScript myself.

Usage

Importing

ES modules using a bundler (Webpack, Parcel, etc.):

import ExifReader from 'exifreader';

CommonJS/Node modules:

const ExifReader = require('exifreader');

AMD modules:

requirejs(['/path/to/exif-reader.js'], function (ExifReader) {
    ...
});

script tag:

<script src="/path/to/exif-reader.js"></script>

Loading tags

const tags = ExifReader.load(fileBuffer);
const imageDate = tags['DateTimeOriginal'].description;
const unprocessedTagValue = tags['DateTimeOriginal'].value;

By default, Exif, IPTC and XMP tags are grouped together. This means that if e.g. Orientation exists in both Exif and XMP, the first value (Exif) will be overwritten by the second (XMP). If you need to separate between these values, pass in an options object with the property expanded set to true:

const tags = ExifReader.load(fileBuffer, {expanded: true});

fileBuffer must be an ArrayBuffer or a SharedArrayBuffer for browsers, or a Buffer for Node. See examples folder for more directions on how to get the file contents in different environments.

Notes

• The description property of tags can change in a minor update. If you want to process a tag's value somehow, use the value property to be sure nothing breaks between updates.
• In Exif data, the full GPS information is split into two different tags for each direction: the coordinate value (GPSLatitude, GPSLongitude) and the reference value (GPSLatitudeRef, GPSLongitudeRef). Use the references to know whether the coordinate is north/south and east/west. Often you will see north and east represented as positive values, and south and west represented as negative values (e.g. in Google Maps). This setup is also used for the altitude using GPSAltitude and GPSAltitudeRef where the latter specifies if it's above sea level (positive) or below sea level (negative).
• Some XMP tags have processed values as descriptions. That means that e.g. an Orientation value of 3 will have Rotate 180 in the description property. If you would like more XMP tags to have a processed description, please file an issue or create a pull request.
• Some text tags use TextDecoder to decode their content. If your specific environment does not support it at all or a specific encoding, you will not be able to see the decoded value. One example is when Node.js wasn't compiled with support for the specific encoding.

Client/Browser Support

The library makes use of the DataView API which is supported in Chrome 9+, Firefox 15+, Internet Explorer 10+, Edge, Safari 5.1+, Opera 12.1+. If you want to support a browser that doesn't have DataView support, you should probably use a polyfill like jDataView.

Node.js has had support for DataView since version 0.12 but ExifReader will also try to polyfill it for versions before that (this is not well tested though).

Examples

Full HTML example pages and a Node.js example are located in the examples/ directory.

Tips

• After parsing the tags, consider deleting the MakerNote tag if you know you will load a lot of files and storing the tags. It can be really large for some manufacturers. See the examples folder to see how you can do that.
• In some cases it can make sense to only load the beginning of the image file. It's unfortunately not possible to know how big the meta data will be in an image, but if you limit yourself to regular Exif tags you can most probably get by with only reading the first 128 kB. This may exclude IPTC and XMP metadata though (and possibly Exif too if they come in an irregular order) so please check if this optimization fits your use case.

Testing

Testing is done with Mocha and Chai. Run with:

npm test

Test coverage can be generated like this:

npm run coverage

Known Limitations

• The descriptions for UserComment, GPSProcessingMethod and GPSAreaInformation are missing for other encodings than ASCII.

Contributing

See CONTRIBUTING.md.

Code of Conduct

This project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.

License

ExifReader uses the Mozilla Public License 2.0 (MPL-2.0). In short that means you can use this library in your project (open- or closed-source) as long as you mention the use of ExifReader and make any changes to ExifReader code available if you would to distribute your project. But please read the full license text to make sure your specific case is covered.

Changelog

• March 2020:
  • Major update to version 3.0. However, the actual change is quite small, albeit a breaking one if you use that functionality (.value on rational tags). Rational values are now kept in their original numerator/denominator pair instead of being calculated into a float. In addition to .value on rational tags some descriptions have also changed into better ones, e.g. ExposureTime now looks like 1/200 instead of 0.005.
• December 2019:
  • Add support for HEIC images.
• November 2019:
  • Add support for ICC color profile tags in JPEG images.
  • Add support for TIFF images.
  • Add support for extended XMP.
  • Add a lot of new tags.
• January 2019:
  • For Node.js, remove dependency of jDataView and explicit dependency of XMLDOM.
  • Add type definitions for TypeScript.
• February, 2018:
  • Change license to Mozilla Public License 2.0 (MPL-2.0).
• December, 2017:
  • Add option to separate different tag groups (Exif, IPTC and XMP).
• February, 2017:
  • Add support for XMP tags.
• December, 2016:
  • Merge IPTC branch.
  • Convert project to JavaScript (ECMAScript 2015) from CoffeeScript, transpiling to ES5 using Babel.
  • Remove need to instantiate the ExifReader object before use.
  • Add UMD support (CommonJS, AMD and global).
  • Publish as npm package.
• September 17, 2014:
  • Lower memory usage by unsetting the file data object after parsing.
  • Add deleteTag method to be able to delete tags that use a lot of memory, e.g. MakerNote.
• September 9, 2013:
  • Make parsing of APP markers more robust. Fixes problems with some pictures.
• July 13, 2013:
  • Throw Error instead of just strings.
• April 23, 2013:
  • Support hybrid JFIF-EXIF image files.
• April 22, 2013:
  • Registered with Bower.
• January 8, 2013:
  • Updated text about browser support.
• January 19, 2012:
  • Added text descriptions for the tags.
• January 1, 2012:
  • First release.