Draft jQuery plugin for drag'n'drop uploader with PUT octet-stream request

jquery.put-upload.js

/*!
Stream signle file upload with PUT octet-stream request.

(c) 2015 Alexey Kinev <[email protected]>
The MIT License, https://opensource.org/licenses/MIT
*/
(function ( $ ) {

  $.fn.putUpload = function( opts ) {
    var el = $( this );

    el.on( 'dragdrop drop' , function( e ) {
      var file = e.originalEvent.dataTransfer.files[0];
      e.stopPropagation();
      e.preventDefault();

      var xhr = new XMLHttpRequest();
      doUpload( el, xhr, file, opts );
    });

    el.on('dragenter',function( e ) {
      e.preventDefault();
    })
    .on('dragleave',function( e ) {
      e.preventDefault();
    })
    .on('dragover',function( e ) {
      e.preventDefault();
    })
    .on( 'click', function ( e ) {
      e.preventDefault();
      doFileInput( el, opts );
    });

    return el;
  }

  function doFileInput( el, opts ) {
    var fileInput = el.find('input[type="file"]');

    if (fileInput.length > 1) {
      fileInput = fileInput.first();
    } else if (fileInput.length == 0) {
      fileInput = $('<input type="file" style="visibility: hidden; height: 0px; width: 0px;">');
      if (opts.accept) {
        fileInput.attr( 'accept', opts.accept );
      }
      el.append(fileInput);
    }

    fileInput.on ( 'click', function ( e ) {
      e.stopPropagation();
    })
      .on ( 'change', function ( e ) {
        var xhr = new XMLHttpRequest();
        doUpload( el, xhr, this.files[0], opts );
      });

    fileInput.click();
  }

  function doUpload( el, xhr, file, opts ) {
    xhr.open("PUT", opts.url, true);
    xhr.setRequestHeader("Cache-Control", "no-cache");
    xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
    xhr.setRequestHeader("X-File-Name", encodeURIComponent(file.fileName));
    xhr.setRequestHeader("X-File-Size", file.fileSize);
    xhr.setRequestHeader("Content-Type", "application/octet-stream");

    xhr.onreadystatechange = function(e) {
      if ( xhr.readyState == 4 ) {
        if ( opts.success ) {
          opts.success( xhr.responseText );
        }
      }
    }

    xhr.upload.onprogress = function(e) {
      if ( e.lengthComputable ) {
        if ( opts.progress ) {
          opts.progress( e );
        }
      }
    }

    el.trigger('startupload', xhr);

    xhr.send( file );
  }
 
}( jQuery ));