API v1 financial_transactions endpoints (#627)

app/controllers/concerns/collection_scope.rb

@@ -0,0 +1,58 @@
+module Concerns::CollectionScope
+  extend ActiveSupport::Concern
+
+  private
+
+  def scope
+    raise NotImplementedError, 'Please override #scope when you use Concerns::CollectionScope'
+  end
+
+  def default_per_page
+    20
+  end
+
+  def max_per_page
+    250
+  end
+
+  def per_page
+    # allow max_per_page and default_per_page to be nil as well
+    if params[:per_page]
+      [params[:per_page].to_i, max_per_page].compact.min
+    else
+      default_per_page
+    end
+  end
+
+  def search_scope
+    s = scope
+    s = s.ransack(params[:q], auth_object: ransack_auth_object).result(distinct: true) if params[:q]
+    s = s.page(params[:page].to_i).per(per_page) if per_page && per_page >= 0
+    s
+  end
+
+  def render_collection(scope)
+    render json: scope, meta: collection_meta(scope)
+  end
+
+  def collection_meta(scope, extra = {})
+    return unless scope.respond_to?(:total_count) && per_page
+
+    {
+      page: params[:page].to_i,
+      per_page: per_page,
+      total_pages: (scope.total_count / [1, per_page].max).ceil,
+      total_count: scope.total_count
+    }.merge(extra)
+  end
+
+  # By default, there are no special ransack search scope authentications.
+  # Controllers can override this to return something else and customize a model's
+  # +ransackable_attributes+ and +ransackable_associations+ to allow searching on more
+  # parameters in one controller than another (e.g. to protect searches that are scoped
+  # to a user, while still allowing all search parameters for another endpoint).
+  def ransack_auth_object
+    nil
+  end
+
+end