How to filter IS NULL in ActiveAdmin?

Question

I've a table with an integer column called "map_id", I want to add an activeadmin filter to filter if this column IS NULL or IS NOT NULL.

How could this be implemented ?

I tried the following filter

filter :map_id, :label => 'Assigned', :as => :select, :collection => {:true => nil, :false => ''}

But, I get the following error message :

undefined method `map_eq' for #

Exegesis

I made some edits, if you have the permissions, please take a quick look and approve them. I think this is a rather common questions and it's wort having it out there with working info. Thanks for asking. – Xenocryst

Answer 1

Not found a good solution but here is a how. filters of Active_admin are accomplished by meta_search, you can override the functions automatically generated by meta_search in your model to get the behavior that you want, the best way is to use the scope since you need to return a relation in order to chain with other query/scopes, as stated here

in your model:

for :as=>:select filters, acitve_admin use the _eq wheres, here is the source code

scope :map_eq, 
        lambda{ |id|
        if(id !='none')
            where( :map_id=> id)
        else
            where( :map_id=> nil)
        end
        }

#re-define the search method:
search_method :map_eq, :type => :integer

in your ative_admin register block:

filter :map_id, :label => 'Assigned', :as => :select, :collection => [['none', 'none'], ['one', 1],['tow', 2]]

# not using :none=>nil because active_admin will igore your nil value so your self-defined scope will never get chained.

Hope this help.

Broadspectrum

I made some edits, if you have the permissions, please take a quick look and approve them. I think this is a rather common questions and it's wort having it out there with working info. Thanks for the initial lead, you made pretty much the whole solution! Thanks! – Xenocryst

Another example: Nested in ActiveAdmin.register MyModel, you add filter :available, :as => :select, :label => "Availability", :collection => { :Available => true, :Assigned => false }. Then, to implement the scope in MyModel: search_method :available_eq; scope :available_eq, ->(_){ where("user_id is #{:not unless ActiveRecord::ConnectionAdapters::Column.value_to_boolean(_)} null") } – Technical

Thank you, @gret -- Would not have figured out how to make my example work without your answer – Technical

Answer 2

If anyone is happening on this thread belatedly, there is now an easy way to filter for null or non null in active admin :

filter :attribute_present, :as => :boolean 
filter :attribute_blank,   :as => :boolean  

It is no longer necessary to add a custom method to the scope to accomplish this.

Humiliate

Note that this can cause SQL errors depending on the data type: it works best with string values and will break when used with datetimes. – Brainpan

And for anyone trying to apply the filter through the query string of a link, you would do admin_resources_path('q[attribute_blank]' => true) – Lanyard

For integer fields use _null or _not_null instead: filter :attribute_not_null, as: :boolean filter :attribute_null, as: :boolean – Defame

@Samuel-innovega answer works for datetimes/timestamps as well - for date/datetime fields use _null or _not_null filter :datetime_attr_null, as: :boolean – Jig

Answer 3

seems search_method doesn't work in recent rails version, here is another solution:

add scope to your model:

  scope :field_blank, -> { where "field is null" }
  scope :field_not_blank, -> { where "field is not null" } 

add to /app/admin/[YOUR MODEL]

   scope :field_blank
   scope :field_not_blank

you will see buttons for these scopes appear (in top section, under model name, not in filter section)

Trousseau

Thanks, this saved my life. Note that ActiveAdmin's default setup doesn't provide a way to clear a scope, so if you want to reset the scope you should manually define an "Everything" scope and add that. – Brainpan

Answer 4

The new version of ActiveAdmin uses Ransacker. I manage to got it working this way:

On the admin

filter :non_nil_map_id, :label => 'Assigned', :as => :select, :collection => [['none', 'none'], ['one', 1],['tow', 2]]

For consistency, I took the same code from @Gret answer just changing the filter name

On your model

ransacker :not_nil_map_id, :formatter => proc {|id|  map_id != 'none' ? id : 'none' } do |parent|
    parent.table[:id]
end

This should trigger a search against nil in case the id is 'none', and active record will return all the nil id entries.

This thread helped a lot.

Oppen

Answer 5

With ransackable scopes:

On the ActiveAdmin resource definition:

filter :map_id, :label => 'Assigned', as: :select, :collection => [['Is Null', 'none'], ['Not null', 'present']]

On your model:

scope :by_map_id, ->(id) { (id == 'none' ? where(map_id: nil) : where('map_id IS NOT NULL')) }

def self.ransackable_scopes(_auth_object = nil)
  %i[by_map_id]
end

Isleen