JavaScript: can I read EXIF data from a file upload input?

Question

I have the following task:

• Offer an <input type=file />
• When the user adds a file:
  • read the EXIF data (specifically, location information if available)
  • send the file and the information from the EXIF to an external API, using Ajax

So, I'd like to use JavaScript to extract some EXIF data when a file is added to the input.

Is this possible?

I know about this question: Can I read Exif data of a picture in the client-side with js? , which refers to http://blog.nihilogic.dk/2008/05/reading-exif-data-with-javascript.html

But my question is (I think?) slightly different - I want to extract the EXIF data before the image is even on my domain, while it's on the user's local filesystem, if you see what I mean. I can access the binary data, so can I get the EXIF too?

Thanks for your advice.

Answer 1

No, sorry. You can't access any of the file data until it's uploaded to the server, which is certainly what the library you linked to does. Once the file is uploaded, you can save it somewhere, re-download it and read EXIF data from it.

The above answer used to be correct, but most modern browsers now allow file access via the js file apis. Feel free to use that, but you should also use a server-side solution if cross-browser support is required.

Answer 2

You can do this on the client with HTML5. You should have an appropriate server based fallback for older browsers that don't support File and FileReader.

You can write your own exif parser or use the jsjpegmeta library(Ben Leslie), which is a simple+awesome library that lets the browser extract the EXIF data from most jpeg files. There is a patch that says it fixes most of the compatibility problems. I haven't tested the patch, but be prepared to fork the project and put on your github hat.

To get the EXIF:

1. Open file dialog: I usually create a button that calls a function to generate the <file input and add a change handler
2. Get the files: In the file change handler ue $(this).get(0).files to get the list of selected files.
3. Parse the exif data: Send the browse results to jsjpegmeta

I had to tweak the library a bit to get it to do what I wanted (I wanted a commonJS library) I also made the tweak identified in issue 1.

Here is a fiddle

Answer 3

I know this may be already solved but I'd like to offer an alternative solution, for the people stumbling upon this question.

There's a new library exifr with which you can do exactly that. It's maintained, actively developed library with focus on performance and works in both nodejs and browser.

Simple example of extracting exif from one file:

document.querySelector('#filepicker').addEventListener('change', async e => {
  let file = e.target.files[0]
  let exifData = await exif.parse(file)
  console.log('exifData', exifData)
})

Complex example of extracting exif from multile files:

document.querySelector('#filepicker').addEventListener('change', async e => {
    let files = Array.from(e.target.files)
    let promises = files.map(exif.parse)
    let exifs = await Promise.all(promises)
    let dates = exifs.map(exif => exif.DateTimeOriginal.toGMTString())
    console.log(`${files.length} photos taken on:`, dates)
})

And you can even extract thumbnail thats embedded in the file:

let img = document.querySelector("#thumb")
document.querySelector('input[type="file"]').addEventListener('change', async e => {
  let file = e.target.files[0]
  img.src = await exifr.thumbnailUrl(file)
})

You can also try out the library's playground and experiment with images and their output, or check out the repository and docs.

Answer 4

Yes with modern browser you can read files contents and so extract exif. the link you show is an example. the problem is that on old browsers IE6-9, FF 3.6- this is not possible. Also you should consider the it is a hard process for browser to read and extract exif from big files.

Answer 5

Shanimal's answer is correct, but it never ceases to amaze me how overcomplicated people make things. Here is an implementation of the jsjpegmeta library that accomplishes the same thing, if you don't need to support multiple file uploads:

<input type="file" accept="image/jpeg" id="input" />
<script src="./jsjpegmeta.js"></script>
<script>
document.getElementById('input').onchange = function(e) {
  var file = e.target.files[0],
    fr = new FileReader();
  fr.onloadend = function() {
    console.log(new JpegMeta.JpegFile(this.result, file.name));
  };
  fr.readAsBinaryString(file);
};
</script>

Answer 6

I love optimism. I love that sploity noise it makes when it's utterly crushed.

No, JavaScript cannot get to EXIF directly; this is not a security issue, it's just something that isn't made available by the browser to the DOM.

The closest you get get is exactly the hack that the other question referred to: have a process on the server side to analyze the image and return the EXIF data via AJAX>.