Merge pull request #279 from samvera/refactor_opt_attrs

refactor optional attributes for linked data search/fetch to pass as hash

Author: elrayle

app/controllers/qa/linked_data_terms_controller.rb

@@ -7,9 +7,15 @@ class Qa::LinkedDataTermsController < ::ApplicationController
   before_action :check_show_subauthority, :check_id_param, only: :show
   before_action :check_uri_param, only: :fetch
   before_action :validate_auth_reload_token, only: :reload
+  before_action :create_request_header_service, only: [:search, :show, :fetch]
 
   delegate :cors_allow_origin_header, to: Qa::ApplicationController
 
+  class_attribute :request_header_service_class
+  self.request_header_service_class = Qa::LinkedData::RequestHeaderService
+
+  attr_reader :request_header_service
+
   # Provide a warning if there is a request for all terms.
   def index
     logger.warn 'Linked data authorities do not support retrieving all terms.'
@@ -35,8 +41,8 @@ def reload
   # Return a list of terms based on a query
   # get "/search/linked_data/:vocab(/:subauthority)"
   # @see Qa::Authorities::LinkedData::SearchQuery#search
-  def search # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
-    terms = @authority.search(query, subauth: subauthority, language: language, replacements: replacement_params, context: context?, performance_data: performance_data?)
+  def search # rubocop:disable Metrics/MethodLength
+    terms = @authority.search(query, request_header: request_header_service.search_header)
     cors_allow_origin_header(response)
     render json: terms
   rescue Qa::ServiceUnavailable
@@ -59,9 +65,9 @@ def search # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
   # get "/show/linked_data/:vocab/:subauthority/:id
   # @see Qa::Authorities::LinkedData::FindTerm#find
   def show # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
-    term = @authority.find(id, subauth: subauthority, language: language, replacements: replacement_params, format: format, performance_data: performance_data?)
+    term = @authority.find(id, request_header: request_header_service.fetch_header)
     cors_allow_origin_header(response)
-    render json: term, content_type: content_type_for_format
+    render json: term, content_type: request_header_service.content_type_for_format
   rescue Qa::TermNotFound
     msg = "Term Not Found - Fetch term #{id} unsuccessful for#{subauth_warn_msg} authority #{vocab_param}"
     logger.warn msg
@@ -89,9 +95,9 @@ def show # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
   # get "/fetch/linked_data/:vocab"
   # @see Qa::Authorities::LinkedData::FindTerm#find
   def fetch # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
-    term = @authority.find(uri, subauth: subauthority, language: language, replacements: replacement_params, format: format, performance_data: performance_data?)
+    term = @authority.find(uri, request_header: request_header_service.fetch_header)
     cors_allow_origin_header(response)
-    render json: term, content_type: content_type_for_format
+    render json: term, content_type: request_header_service.content_type_for_format
   rescue Qa::TermNotFound
     msg = "Term Not Found - Fetch term #{uri} unsuccessful for#{subauth_warn_msg} authority #{vocab_param}"
     logger.warn msg
@@ -147,6 +153,10 @@ def check_show_subauthority
       end
     end
 
+    def create_request_header_service
+      @request_header_service = request_header_service_class.new(request, params)
+    end
+
     def init_authority
       @authority = Qa::Authorities::LinkedData::GenericAuthority.new(vocab_param)
     rescue Qa::InvalidLinkedDataAuthority => e
@@ -190,64 +200,19 @@ def id
       params[:id]
     end
 
-    def language
-      request_language = request.env['HTTP_ACCEPT_LANGUAGE']
-      request_language = request_language.scan(/^[a-z]{2}/).first if request_language.present?
-      params[:lang] || request_language
-    end
-
     def subauthority
       params[:subauthority]
     end
 
-    def replacement_params
-      params.reject { |k, _v| ['q', 'vocab', 'controller', 'action', 'subauthority', 'lang', 'id'].include?(k) }
-    end
-
     def subauth_warn_msg
       subauthority.blank? ? "" : " sub-authority #{subauthority} in"
     end
 
-    def format
-      return 'json' unless params.key?(:format)
-      return 'json' if params[:format].blank?
-      params[:format]
-    end
-
-    def jsonld?
-      format.casecmp?('jsonld')
-    end
-
-    def n3?
-      format.casecmp?('n3')
-    end
-
-    def ntriples?
-      format.casecmp?('ntriples')
-    end
-
-    def content_type_for_format
-      return 'application/ld+json' if jsonld?
-      return 'text/n3' if n3?
-      return 'application/n-triples' if ntriples?
-      'application/json'
-    end
-
-    def context?
-      context = params.fetch(:context, 'false')
-      context.casecmp?('true')
-    end
-
     def details?
       details = params.fetch(:details, 'false')
       details.casecmp?('true')
     end
 
-    def performance_data?
-      performance_data = params.fetch(:performance_data, 'false')
-      performance_data.casecmp?('true')
-    end
-
     def validate_auth_reload_token
       token = params.key?(:auth_token) ? params[:auth_token] : nil
       valid = Qa.config.valid_authority_reload_token?(token)

app/services/qa/linked_data/authority_url_service.rb

@@ -7,14 +7,17 @@ class << self
         # @param action_config [Qa::Authorities::LinkedData::SearchConfig | Qa::Authorities::LinkedData::TermConfig] action configuration for the authority
         # @param action [Symbol] action with valid values :search or :term
         # @param action_request [String] the request the user is making of the authority (e.g. query text or term id/uri)
-        # @param substitutions [Hash] variable-value pairs to substitute into the URL template (optional)
-        # @param subauthority [String] name of a subauthority (optional)
-        # @param language [Array<Symbol>] languages for filtering returned literals (optional)
+        # @param request_header [Hash] optional attributes that can be appended to the generated URL
+        # @option replacements [Hash] variable-value pairs to substitute into the URL template
+        # @option subauthority [String] name of a subauthority
+        # @option language [Array<Symbol>] languages for filtering returned literals
         # @return a valid URL that submits the action request to the external authority
-        def build_url(action_config:, action:, action_request:, substitutions: {}, subauthority: nil, language: nil) # rubocop:disable Metrics/ParameterLists
+        # @note All parameters after request_header are deprecated and will be removed in the next major release.
+        def build_url(action_config:, action:, action_request:, request_header: {}, substitutions: {}, subauthority: nil, language: nil) # rubocop:disable Metrics/ParameterLists
+          request_header = build_request_header(substitutions, subauthority, language) if request_header.empty?
           action_validation(action)
           url_config = action_config.url_config
-          selected_substitutions = url_config.extract_substitutions(combined_substitutions(action_config, action, action_request, substitutions, subauthority, language))
+          selected_substitutions = url_config.extract_substitutions(combined_substitutions(action_config, action, action_request, request_header))
           Qa::IriTemplateService.build_url(url_config: url_config, substitutions: selected_substitutions)
         end
 
@@ -25,10 +28,12 @@ def action_validation(action)
             raise Qa::UnsupportedAction, "#{action} Not Supported - Action must be one of the supported actions (e.g. :term, :search)"
           end
 
-          def combined_substitutions(action_config, action, action_request, substitutions, subauthority, language) # rubocop:disable Metrics/ParameterLists
+          def combined_substitutions(action_config, action, action_request, request_header)
+            substitutions = request_header.fetch(:replacements, {})
             substitutions[action_request_variable(action_config, action)] = action_request
-            substitutions[action_subauth_variable(action_config)] = action_subauth_variable_value(action_config, subauthority) if supports_subauthorities?(action_config) && subauthority.present?
-            substitutions[action_language_variable(action_config)] = language_value(language) if supports_language_parameter?(action_config) && language.present?
+            substitutions[action_subauth_variable(action_config)] = action_subauth_variable_value(action_config, request_header)
+            substitutions[action_language_variable(action_config)] = language_value(action_config, request_header)
+            substitutions.reject { |_k, v| v.nil? }
             substitutions
           end
 
@@ -37,29 +42,38 @@ def action_request_variable(action_config, action)
             action_config.qa_replacement_patterns[key]
           end
 
-          def supports_subauthorities?(action_config)
-            action_config.supports_subauthorities?
-          end
-
           def action_subauth_variable(action_config)
             action_config.qa_replacement_patterns[:subauth]
           end
 
-          def action_subauth_variable_value(action_config, subauthority)
-            action_config.subauthorities[subauthority.to_sym]
-          end
-
-          def supports_language_parameter?(action_config)
-            action_config.supports_language_parameter?
+          def action_subauth_variable_value(action_config, request_header)
+            subauth = request_header.fetch(:subauthority, nil)
+            return nil unless subauth && action_config.supports_subauthorities?
+            action_config.subauthorities[subauth.to_sym]
           end
 
           def action_language_variable(action_config)
             action_config.qa_replacement_patterns[:lang]
           end
 
-          def language_value(language)
-            return nil if language.blank?
-            language.first
+          def language_value(action_config, request_header)
+            return nil unless action_config.supports_language_parameter?
+            request_header.fetch(:language, []).first
+          end
+
+          # This is providing support for calling build_url with individual parameters instead of the request_header.
+          # This is deprecated and will be removed in the next major release.
+          def build_request_header(substitutions, subauthority, language) # rubocop:disable Metrics/CyclomaticComplexity
+            return {} if substitutions.blank? && subauthority.blank? && language.blank?
+            Qa.deprecation_warning(
+              in_msg: 'Qa::LinkedData::AuthorityUrlService',
+              msg: "individual attributes for options (e.g. substitutions, subauthority, language) are deprecated; use request_header instead"
+            )
+            request_header = {}
+            request_header[:replacements] = substitutions unless substititions.blank?
+            request_header[:subauthority] = subauthority unless subauthority.blank?
+            request_header[:language] = language unless language.blank?
+            request_header
           end
       end
     end

app/services/qa/linked_data/request_header_service.rb

@@ -0,0 +1,97 @@
+# Service to construct a request header that includes optional attributes for search and fetch requests.
+module Qa
+  module LinkedData
+    class RequestHeaderService
+      attr_reader :request, :params
+
+      # @param request [HttpRequest] request from controller
+      # @param params [Hash] attribute-value pairs holding the request parameters
+      # @option subauthority [String] the subauthority to query
+      # @option lang [Symbol] language used to select literals when multi-language is supported (e.g. :en, :fr, etc.)
+      # @option performance_data [Boolean] true if include_performance_data should be returned with the results; otherwise, false (default: false)
+      # @option context [Boolean] true if context should be returned with the results; otherwise, false (default: false) (search only)
+      # @option format [String] return data in this format (fetch only)
+      # @note params may have additional attribute-value pairs that are passed through via replacements (only configured replacements are used)
+      def initialize(request, params)
+        @request = request
+        @params = params
+      end
+
+      # Construct request parameters to pass to search_query (linked data module).
+      # @returns [Hash] parsed out attribute-value pairs that are required for the search query
+      # @see Qa::Authorities::LinkedData::SearchQuery
+      def search_header
+        header = {}
+        header[:subauthority] = params.fetch(:subauthority, nil)
+        header[:user_language] = user_language
+        header[:performance_data] = performance_data?
+        header[:context] = context?
+        header[:replacements] = replacements
+        header
+      end
+
+      # Construct request parameters to pass to fetching a term (linked data module).
+      # @returns [Hash] parsed out attribute-value pairs that are required for the term fetch.
+      # @see Qa::Authorities::LinkedData::FindTerm
+      def fetch_header
+        header = {}
+        header[:subauthority] = params.fetch(:subauthority, nil)
+        header[:user_language] = user_language
+        header[:performance_data] = performance_data?
+        header[:format] = format
+        header[:replacements] = replacements
+        header
+      end
+
+      # @returns [String] the response header content type based on requested format
+      def content_type_for_format
+        case format
+        when 'jsonld'
+          'application/ld+json'
+        when 'n3'
+          'text/n3'
+        when 'ntriples'
+          'application/n-triples'
+        else
+          'application/json'
+        end
+      end
+
+      private
+
+        # filter literals in results to this language
+        def user_language
+          request_language = request.env['HTTP_ACCEPT_LANGUAGE']
+          request_language = request_language.scan(/^[a-z]{2}/).first if request_language.present?
+          lang = params[:lang] || request_language
+          lang.present? ? Array(lang) : nil
+        end
+
+        # include extended context in the results if true (applies to search only)
+        def context?
+          context = params.fetch(:context, 'false')
+          context.casecmp?('true')
+        end
+
+        # include performance data in the results if true
+        def performance_data?
+          performance_data = params.fetch(:performance_data, 'false')
+          performance_data.casecmp?('true')
+        end
+
+        # any params not specifically handled are passed through via replacements
+        def replacements
+          params.reject do |k, _v|
+            ['q', 'vocab', 'controller', 'action', 'subauthority', 'lang', 'id',
+             'context', 'performance_data', 'response_header', 'format'].include?(k)
+          end
+        end
+
+        # results are returned in the format (applies to fetch only)
+        def format
+          f = params.fetch(:format, 'json').downcase
+          ['jsonld', 'n3', 'ntriples'].include?(f) ? f : 'json'
+        end
+    end
+  end
+end