在活动存储中保存图像（签名板）的同时提高ActiveSupport :: MessageVerifier :: InvalidSignature

Question

我正在尝试在Active Storage中添加Signature Pad图像。但它一直都低于筹码。

ActiveSupport::MessageVerifier::InvalidSignature

我的表单很简单

<%= f.input_field :engineer_signature, as: :hidden, class: 'signature_pad_input' %>
<div class="signature_pad text-center">
  <div class="signature_pad_body">
      <canvas></canvas>
  </div>
  <div class="signature_pad_footer">
    <div class="text-muted">Sign above</div>
      <button type="button" class="btn btn-default signature_pad_clear">Clear</button>
        <%= f.button :submit, 'Save', class: 'btn btn-success signature_pad_save'  %>
      </div>
</div>

Javascript文件是

$(document).ready(function() {
   var canvas = document.querySelector("canvas");
   if (canvas){
     canvas.height = canvas.offsetHeight;
     canvas.width = canvas.offsetWidth;
     window.onresize = resizeCanvas(canvas);
     resizeCanvas(canvas);
     signature_pad = new SignaturePad(canvas);

     $('.signature_pad_clear').click(function() { 
        signature_pad.clear(); console.log("SignaturePad Cleared"); });
     $('.signature_pad_save').click(function(event) {
       if (signature_pad.isEmpty()){
         alert('Firma Electronica requerida antes de proceder');
         event.preventDefault();
       } else {
         $('.signature_pad_input').val(signature_pad.toDataURL());
     }
    });
   }
});

有帮助吗？