Rails controller#update giving incorrect type for params

Question

I want to update a model using controller#update. I want to do this via AJAX and without having a hidden form or any DOM elements to keep in sync with my JS data.

How can I submit data to a controller#update via jQuery ajax?

My JS:

$.ajax({
  type: "PATCH",
  url: "/uploads/" + current_upload.id,
  data: { 
    "upload[user]": user.id,
    "upload[upload]": current_upload.id 
  }
}).done(function( msg ) {
  alert( "Data Saved: " + msg );
});

My Controller:

  def update
    @upload = Upload.find(params[:id])

    # update the model.
    if @upload.update(upload_params)
      redirect_to @post
    else
      render 'edit'
    end
  end

  private
    def upload_params
      # permit! allows all attributes.
      params.require(:upload).permit(:user)
    end

Error:

User(#70101060061080) expected, got String(#70101055761460)

Answer 1

Change "upload[user]": user.id to be "upload[user_id]": user.id.

Within Rails, it's trying to assign user (a user instance) to be the string you're passing in via user.id, and complaining about the type mismatch.

Answer 2

It sounds like your request parameters have the "upload" parameter set to be "13" rather than a hash.