Uppie Save Abandoned

Cross-browser directory and multi-file upload library

Project README


Cross-browser file and directory and upload library

uppie is a tiny JavaScript library which helps you with file and directory uploads in browsers. It supports all current and past implementations of multi-file and directory uploads and provides you with a FormData object you can submit directly to a server through either XMLHttpRequest or fetch. Both the <input type="file"> element and drag-and-drop are supported.


npm install uppie
import uppie from 'uppie';

uppie(document.querySelector('#file'), async (e, formData, files) => {
  await fetch('/upload', {method: 'POST', body: formData});

Browser support

files via input[type=file] files via DnD directories via input[type=file] directories via DnD
Firefox yes yes yes (50+) yes (50+)
Chrome yes yes yes (29+) yes (29+)
Edge yes yes yes (13+) yes (14+)
Safari yes yes yes (11.1+) yes (11.1+)


  • Empty directories are excluded from the results by all browsers as dictated by the spec.
  • Firefox and Safari exclude files and directories starting with a ..


uppie(node, [opts], callback)

  • node Node or NodeList: One or more DOM nodes. If a <input type="file"> is given, uppie will monitor it for change events. Any other element type will be enabled as a dropzone and watched for drop events. If you want to use both on the same element, use a hidden <input> and forward the click event.
  • opts Object: A options object which can contain:
    • name: The name attribute for creating the FormData entries. Default: "files[]".
  • callback Function: callback which is called every time the selected files change or when files are dropped in the dropzone.

The callback receives

  • event Event: the original event. Useful for calling event.stopPropagation().
  • formData FormData: FormData object to be used for XHR2 uploading.
  • files Array: Array of paths for preview purposes.

FormData format

name defaults to "files[]", filename will be the full path to the file, with / used as path separator. Does not include a leading slash. Make sure to sanitize filename on the server before writing it to the disk to prevent exploits involving .. in the path. Example FormData:

Content-Disposition: form-data; name="files[]"; filename="docs/1.txt"
Content-Type: text/plain

Content-Disposition: form-data; name="files[]"; filename="docs/path/2.txt"
Content-Type: text/plain

Content-Disposition: form-data; name="files[]"; filename="docs/path/to/3.txt"
Content-Type: text/plain
  • multiple: allow multiple files or directories to be selected.
  • webkitdirectory: enable directory uploads.

PHP example

Below is example for PHP 7.0 and possibly earlier versions. PHP does not parse the path from the filename field, so it is necessary to submit the path through other means, like as separate FormData fields as done in the example.

const uppie = new Uppie();
uppie(document.documentElement, (event, formData, files) => {
  files.forEach(path => {
    formData.append("paths[]", path);

  const xhr = new XMLHttpRequest();
  xhr.open('POST', 'upload.php');

And in upload.php:

foreach ($_FILES['files']['name'] as $i => $name) {
  if (strlen($_FILES['files']['name'][$i]) > 1) {
    $fullpath = strip_tags($_POST['paths'][$i]);
    $path = dirname($fullpath);

    if (!is_dir('uploads/'.$path)){
    if (move_uploaded_file($_FILES['files']['tmp_name'][$i], 'uploads/'.$fullpath)) {
        echo '<li>'.$name.'</li>';

Note that PHP's upload limits might need to be raised depending on use case.

© silverwind, distributed under BSD licence

Open Source Agenda is not affiliated with "Uppie" Project. README Source: silverwind/uppie
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