module Spree
  module Api
    class TaxonomiesController < Spree::Api::BaseController

      def index
        @taxonomies = Taxonomy.accessible_by(current_ability, :read).order('name').includes(:root => :children).
                      ransack(params[:q]).result.
                      page(params[:page]).per(params[:per_page])
        last_taxonomy = Spree::Taxonomy.order("updated_at ASC").last
        if stale?(:etag => last_taxonomy, :last_modified => last_taxonomy.updated_at)
          respond_with(@taxonomies)
        end
      end

      def show
        @taxonomy = Taxonomy.accessible_by(current_ability, :read).find(params[:id])
        respond_with(@taxonomy)
      end

      # Because JSTree wants parameters in a *slightly* different format
      def jstree
        show
      end

      def create
        authorize! :create, Taxonomy
        @taxonomy = Taxonomy.new(params[:taxonomy])
        if @taxonomy.save
          respond_with(@taxonomy, :status => 201, :default_template => :show)
        else
          invalid_resource!(@taxonomy)
        end
      end

      def update
        authorize! :update, taxonomy
        if taxonomy.update_attributes(params[:taxonomy])
          respond_with(taxonomy, :status => 200, :default_template => :show)
        else
          invalid_resource!(taxonomy)
        end
      end

      def destroy
        authorize! :destroy, taxonomy
        taxonomy.destroy
        respond_with(taxonomy, :status => 204)
      end

      private

      def taxonomy
        @taxonomy ||= Taxonomy.accessible_by(current_ability, :read).find(params[:id])
      end

    end
  end
end

module Spree
  module Api
    class TaxonomiesController < Spree::Api::BaseController

      def index
        @taxonomies = Taxonomy.accessible_by(current_ability, :read).order('name').includes(:root => :children).
                      ransack(params[:q]).result.
                      page(params[:page]).per(params[:per_page])
        respond_with(@taxonomies)
      end

      def show
        @taxonomy = Taxonomy.accessible_by(current_ability, :read).find(params[:id])
        respond_with(@taxonomy)
      end

      # Because JSTree wants parameters in a *slightly* different format
      def jstree
        show
      end

      def create
        authorize! :create, Taxonomy
        @taxonomy = Taxonomy.new(params[:taxonomy])
        if @taxonomy.save
          respond_with(@taxonomy, :status => 201, :default_template => :show)
        else
          invalid_resource!(@taxonomy)
        end
      end

      def update
        authorize! :update, taxonomy
        if taxonomy.update_attributes(params[:taxonomy])
          respond_with(taxonomy, :status => 200, :default_template => :show)
        else
          invalid_resource!(taxonomy)
        end
      end

      def destroy
        authorize! :destroy, taxonomy
        taxonomy.destroy
        respond_with(taxonomy, :status => 204)
      end

      private

      def taxonomy
        @taxonomy ||= Taxonomy.accessible_by(current_ability, :read).find(params[:id])
      end

    end
  end
end

Remove ConditionalGet caching from taxonomies controller
[api] Remove ConditionalGet caching from taxonomies controller

This was being tempremental in my testing
