title: How to get file upload progress?
body: <p>I am new to AOR and redux-sagas and I am currently working on a list view drag-and-drop and upload capability. I want the user to be able to drag and drop files and see current upload progress and status from the List view.</p>
  
  <p>The prototype of the component looks like this: </p>
  
  <pre><code>// ...
  &lt;Dropzone onDrop={this.onDrop} onDragLeave={this.onDragLeave} onDragEnter={this.onDragEnter} ref={(node) =&gt; {this.dropzoneRef = node;}} disableClick disablePreview style={{}}&gt;
      // Dropped files will appear here, with the upload progress
      &lt;Card style={{marginBottom: "1em"}}&gt;
          &lt;CardTitle&gt;Picture.jpg&lt;/CardTitle&gt;
          &lt;CardText&gt;
               // The progress bar will show the upload progress
               &lt;LinearProgress value={50} mode="determinate" /&gt;
          &lt;/CardText&gt;
      &lt;/Card&gt;
      &lt;List {...props} actions={&lt;FileActions onUploadClick={() =&gt; {this.dropzoneRef.open()}} /&gt;}&gt;
          &lt;Datagrid&gt;
              &lt;TextField source="name" /&gt;
              &lt;DateField source="createdAt" /&gt;
              &lt;EditButton /&gt;
          &lt;/Datagrid&gt;
      &lt;/List&gt;
  &lt;/Dropzone&gt;
  </code></pre>
  
  <p>the <code>onDrop</code> callback receives the dropped files, and that's where the upload needs to be handled. That's where I am bit puzzled about how I should handle the problem. </p>
  
  <p>I <a href="https://marmelab.com/admin-on-rest/RestClients.html#decorating-your-rest-client-example-of-file-upload" rel="nofollow noreferrer">understand I have to decorate my REST client in order to be able to upload my files</a>. But how can I plug some functions in order to send the upload progress of each files to my component? </p>