Paperclip delete image via ajax - ruby-on-rails

Question

I want to delete the image via Ajax.
I'm using Paperclip for the upload.
I learned that for deleting the image all I have to do is to set it to nil.
Example:
#meth.picture = nil # this works
Error msg:
Paperclip::AdapterRegistry::NoHandlerError (No handler found for "nil"):
app/controllers/meths_controller.rb:116:in `block in update'
app/controllers/meths_controller.rb:115:in `update'
code:
$(function() {
$('#delete_image').on("click", function() {
$('#image > img').remove();
//console.log("??");
var url = document.URL.split("/");
var meth_id = url[4];
console.log(meth_id);
$.ajax({
url: '/Methoden/'+meth_id,
type: 'PATCH',
dataType: 'json',
data: {"meth": {"picture": "nil"}},
complete: function (jqXHR, textStatus) {
},
success: function (data, textStatus, jqXHR) {
console.log(" ?? profit");
},
error: function (jqXHR, textStatus, errorThrown) {
}
});
});
});
With the help from Зелёный, I did the following:
data: {"meth": "delete_image"}
Then in my controller update method:
if params[:meth] == "delete_image"
#meth.picture = nil
#meth.save
end

Answer 1

Problem is what you pass string ((No handler found for "nil")) to the method #meth.picture.
Send instead "nil" something like "delete" or "clear" and check in controller if params[:meth] == "delete" do #meth.picture = nil else do something other.