如何在RoR中解析上传文件的内容

Rails.application.routes.draw do
  post 'upload', to: 'uploads#upload'
end

class UploadsController< ApplicationController
  def upload
    file = params[:file]
    if file.present?
      filename = file.original_filename
      content_type = file.content_type
      tempfile = file.tempfile
      data = tempfile.read
      render json: { filename: filename, content_type: content_type, data: data }, status: :ok
    else
      render json: { error: 'No file uploaded' }, status: :bad_request
    end
  end
end

<form id="upload-form">
 <input type="file" name="file" />
 <button type="submit">Upload</button>
</form><script>
  document.getElementById('upload-form').addEventListener('submit', function(event) {
    event.preventDefault();
    const formData = new FormData(event.target);
    fetch('/upload', {
      method: 'POST',
      body: formData
    })
    .then(response => response.json())
    .then(data => console.log(data))
    .catch(error => console.error(error));
  });
</script>