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exifreader

3.12.6 • Public • Published

ExifReader

ExifReader is a JavaScript library that parses image files and extracts the metadata. It can also extract an embedded thumbnail. It can be used either in a browser or from Node. Supports JPEG, TIFF, PNG, HEIC, and WebP files with Exif, IPTC, XMP, and ICC meta data (depending on file type).

ExifReader is highly and easliy configurable and the resulting bundle can be as small as 3 KiB (gzipped) if you're only interested in a few tags (e.g. date and/or GPS values). See section below on making a custom build.

ExifReader supports module formats ESM, AMD, CommonJS, and globals and can therefore easily be used from Webpack, RequireJS, Browserify, Node etc.

You can try it out on the examples site.

Support table

File type Exif IPTC XMP ICC Thumbnail
JPEG yes yes yes yes yes
TIFF yes yes yes yes no
PNG no no yes no no
HEIC/HEIF yes no no yes no
WebP yes no yes yes yes

If you're missing something that you think should be supported, file an issue with an attached example image and I'll see what I can do.

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 git@github.com: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 module syntax:

import ExifReader from 'exifreader';

NOTE: TypeScript/Angular seems to sometimes have problems when using the default export. If you're seeing issues, use this syntax instead:

import * as 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 the examples site for more directions on how to get the file contents in different environments.

GPS

If expanded: true is specified in the options, there will be a gps group. This group currently contains Latitude, Longitude, and Altitude which will be negative for values that are south of the equator, west of the IRM, or below sealevel. These are often more convenient values for regular use. For some elaboration or if you need the original values, see Notes below.

Using the thumbnail

The thumbnail and its details will be accessible through tags['Thumbnail']. There is information about e.g. width and height, and the thumbnail image data is stored in tags['Thumbnail'].image.

How you use it is going to depend on your environment. For a web browser you can either use the raw byte data in tags['Thumbnail'].image and use it the way you want, or you can use the helper property tags['Thumbnail'].base64 that is a base64 representation of the image. It can be used for a data URI like this:

const tags = ExifReader.load(fileBuffer);
imageElement.src = 'data:image/jpg;base64,' + tags['Thumbnail'].base64;

If you're using node, you can store it as a new file like this:

const fs = require('fs');
const tags = ExifReader.load(fileBuffer);
fs.writeFileSync('/path/to/new/thumbnail.jpg', Buffer.from(tags['Thumbnail'].image));

See the examples site for more details.

Optimizing build size

The most important step will be to use a custom build so please do that.

If you are using Webpack and are only targeting web browsers, make sure to add this to your Webpack config (probably the webpack.config.js file):

    node: {
        Buffer: false
    }

Buffer is only used in Node.js but if Webpack sees a reference to it it will include a Buffer shim for browsers. This configuration will stop Webpack from doing that.

Configure a custom build

Configuring a custom build can reduce the bundle size significantly.

NOTE 1: This functionality is in beta but should work fine. Please file an issue if you're having problems or ideas on how to make it better.

NOTE 2: This only changes the built file (exifreader/dist/exif-reader.js), not the source code. That means it's not possible to use the ES module (from the src folder) or any tree shaking to get the benefit of a custom build. Tree shaking will actually have close to no effect at all here so don't rely on it.

This is for npm users that use the built file. To specify what functionality you want you can either use include pattern (start with an empty set and include) or exclude pattern (start with full functionality and exclude). If an include pattern is set, excludes will not be used.

For Exif and IPTC it's also possible to specify which tags you're interested in. Those tag groups have huge dictionaries of tags and you may not be interested in all of them. (Note that it's not possible to specify tags to exclude.)

The configuration is added to your project's package.json file.

Example 1: Only include JPEG files and Exif tags (this makes the bundle almost half the size of the full one (non-gzipped)):

"exifreader": {
    "include": {
        "jpeg": true,
        "exif": true
    }
}

Example 2: Only include TIFF files, and the Exif DateTime tag and the GPS tags (resulting bundle will be ~16 % of a full build):

"exifreader": {
    "include": {
        "tiff": true,
        "exif": [
            "DateTime",
            "GPSLatitude",
            "GPSLatitudeRef",
            "GPSLongitude",
            "GPSLongitudeRef",
            "GPSAltitude",
            "GPSAltitudeRef"
        ]
    }
}

Example 3: Exclude XMP tags:

"exifreader": {
    "exclude": {
        "xmp": true
    }
}

Then, if you didn't install ExifReader yet, just run npm install exifreader. Otherwise you have to re-build the library:

npm rebuild exifreader

After that the new bundle is here: node_modules/exifreader/dist/exif-reader.js

If you're using the include pattern config, remember to include everything you want to use. If you want xmp and don't specify any file types, you will get "Invalid image format", and if you specify jpeg but don't mention any tag types no tags will be found.

Possible modules to include or exclude:

Module Description
jpeg JPEG images.
tiff TIFF images.
png PNG images.
heic HEIC/HEIF images.
webp WebP images.
file JPEG file details: image width, height etc.
png_file PNG file details: image width, height etc.
exif Regular Exif tags. If excluded, will also exclude thumbnail. For TIFF files, excluding this will also exclude IPTC, XMP, and ICC.
iptc IPTC tags.
xmp XMP tags.
icc ICC color profile tags.
thumbnail Thumbnail. Needs exif.

Notes

  • 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). If you don't want to calculate the final values yourself, see the section on GPS for pre-calculated ones.
  • 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.
  • 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.

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 on the examples site.

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 site 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

  • May 2020:
    • Add support for WebP images.
    • Add support for ICC tags in TIFF images.
  • April 2020:
    • Add support for IPTC and XMP tags in TIFF images.
    • Add functionality to create a custom build to reduce bundle size.
  • March 2020:
    • Add support for PNG images.
    • Add support for thumbnails in JPEGs.
    • 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:
  • January 8, 2013:
    • Updated text about browser support.
  • January 19, 2012:
    • Added text descriptions for the tags.
  • January 1, 2012:
    • First release.

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Install

npm i exifreader

DownloadsWeekly Downloads

16,396

Version

3.12.6

License

MPL-2.0

Unpacked Size

476 kB

Total Files

46

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