Impressionist Ruby Library

If you are using Mongoid instead of ActiveRecord, generate the initializer with the Mongoid flag and configure the ORM setting.

1. Run the generator:

rails g impressionist --orm mongoid

2. Update the generated config/initializer/impressionist.rb file:

Impressionist.setup do |config|
  config.orm = :mongoid
end

rails g impressionist --orm mongoid

# config/initializer/impressionist.rb
Impressionist.setup do |config|
  config.orm = :mongoid
end

Version 1.5.2 introduces a new params column to the impressions table. If you are upgrading from version 1.5.1, you must manually add this column and its associated index via a migration before performing the gem upgrade to avoid errors.

add_column :impressions, :params, :text

add_index :impressions, [:impressionable_type, :impressionable_id, :params], :name => "poly_params_request_index", :unique => false

To install Impressionist, add the gem to your Gemfile based on your Rails version, install with Bundler, generate the migration, and run it.

For Rails 6:

gem 'impressionist'

For Rails 5 or lower:

gem 'impressionist', '~>1.6.1'

Then run:

bundle install
rails g impressionist
rake db:migrate

To enable automatic updating of impression counters on your model, use the is_impressionable method with the counter_cache: true option.

When counter_cache is enabled, Impressionist will use the UpdateCounters logic to calculate the difference between total impressions and the currently cached value, then update the specified column on your model.

Unique Impression Filtering

You can control how 'unique' impressions are counted using the unique option:

• Default behavior: If you set unique: true, the system defaults to filtering by :ip_address to count unique impressions.
• Custom filter: You can provide a specific column name (e.g., :session_id) to unique: to define what constitutes a unique impression.
• Disable uniqueness: Set unique: false to use :all as the filter, effectively counting every impression regardless of uniqueness.

To track impressions on a model, include the Impressionist::IsImpressionable module and call the is_impressionable class method. This sets up a has_many association to an impressions table using a polymorphic :as => :impressionable relationship. By default, impressions are deleted when the parent model is destroyed (dependent: :delete_all).

You can pass an options hash to is_impressionable to configure how impression data is cached.