Rails wrong number of arguments (given 0, expected 1)

Question

I have this method in my groups controller.

def remove
  @usergroup = Usergroup.where(group_id: params[:group_id]).destroy
  redirect_to groups_path
end

And

<%= link_to 'Remove', { controller: "groups", action: "remove" },
    group_id: @group.id, data: { confirm: 'Are you sure?' } %>

When I click remove and confirm the removal, I get this error.

I am a bit confused because the id of the group is 6 and it should be. For the group I am trying to remove somebody from. Why would it be giving me a no arguments error for this?

This is a route I have set. I believe this is the issue. get 'groups/remove/:id', to: 'groups#remove'

Sebastián Palma · Accepted Answer · 2017-11-26 22:43:46Z

3

As you're using where, and it returns a Model::ActiveRecord_Relation, then you need to "identify" the object you want to destroy, that's, accessing the singular element, you can do it by accessing a specific element in the result, like:

Usergroup.where('group_id = ?', params[:group_id]).first.destroy

Or to use destroy_all, which would take all the objects within that result and destroy all of them:

Usergroup.where('group_id = ?', params[:group_id]).destroy_all

edited Nov 26, 2017 at 22:43

answered Nov 26, 2017 at 22:41

Sebastián Palma

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5 Comments

Trenton Tyler Over a year ago

After trying your method I seem to be getting this error: undefined method destroy' for nil:NilClass`

Sebastián Palma Over a year ago

So your query using where has an empty result.

Ilya Over a year ago

.where().first => .find_by

Trenton Tyler Over a year ago

Please see updated question. I believe this has something to do with the route.

Sebastián Palma Over a year ago

You're using params[:group_id], but your route and your params say id, try instead using id in both cases @TrentonTyler.

Dave · Accepted Answer · 2017-11-26 22:38:56Z

0

Not sure if this is the problem but your setting a variable to something that youve destroyed

answered Nov 26, 2017 at 22:38

Dave

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Comments

Dave · Accepted Answer · 2017-11-26 22:53:43Z

0

Your params are id =6 not group_id =6

answered Nov 26, 2017 at 22:53

Dave

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2 Comments

Sebastián Palma Over a year ago

This can be added as a comment Dave.

Dave Over a year ago

Yeah sorry my phone is flidding out.

Ali · Accepted Answer · 2017-11-26 23:08:36Z

I think its because of your use of where, you are trying to call destroy on a list of objects because when you call ActiveRecord .where it returns a list even if there is only one. You should try to do it like this instead:

@group = Usergroup.find_by(group_id: params[:group_id])
if @group
  @group.destroy
...

and make your link_to like this:

<%= link_to 'Remove', name_of_path_here_path(group_id: @group.id), confirm: 'Are you sure?', method: :delete %>

Also, remember that you could use the Restful routes pattern commonly used in Rails: routes.rb (ex: resources :usergroups). You can also alias routes with the as: :name_of_route_here. To double check your routes you can open up terminal and run bundle exec rake routes and on the left column of the routes is the name of the route helper. Hope this helps.

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