Extract methods related to request building into its own module

lib/blacklight.rb

@@ -10,6 +10,7 @@ module Blacklight
   autoload :Solr, 'blacklight/solr'
 
   autoload :SolrHelper, 'blacklight/solr_helper'
+  autoload :RequestBuilders, 'blacklight/request_builders'
 
   autoload :Exceptions, 'blacklight/exceptions'
 

lib/blacklight/request_builders.rb

@@ -0,0 +1,288 @@
+module Blacklight
+  ##
+  # This module contains methods that are specified by SolrHelper.solr_search_params_logic
+  # They transform user parameters into parameters that are sent as a request to Solr when
+  # RequestBuilders#solr_search_params is called.
+  #
+  module RequestBuilders
+    extend ActiveSupport::Concern
+
+    included do
+      # We want to install a class-level place to keep 
+      # solr_search_params_logic method names. Compare to before_filter,
+      # similar design. Since we're a module, we have to add it in here.
+      # There are too many different semantic choices in ruby 'class variables',
+      # we choose this one for now, supplied by Rails. 
+      class_attribute :solr_search_params_logic
+
+      # Set defaults. Each symbol identifies a _method_ that must be in
+      # this class, taking two parameters (solr_parameters, user_parameters)
+      # Can be changed in local apps or by plugins, eg:
+      # CatalogController.include ModuleDefiningNewMethod
+      # CatalogController.solr_search_params_logic += [:new_method]
+      # CatalogController.solr_search_params_logic.delete(:we_dont_want)
+      self.solr_search_params_logic = [:default_solr_parameters , :add_query_to_solr, :add_facet_fq_to_solr, :add_facetting_to_solr, :add_solr_fields_to_query, :add_paging_to_solr, :add_sorting_to_solr, :add_group_config_to_solr ]
+    end
+
+    # @returns a params hash for searching solr.
+    # The CatalogController #index action uses this.
+    # Solr parameters can come from a number of places. From lowest
+    # precedence to highest:
+    #  1. General defaults in blacklight config (are trumped by)
+    #  2. defaults for the particular search field identified by  params[:search_field] (are trumped by) 
+    #  3. certain parameters directly on input HTTP query params 
+    #     * not just any parameter is grabbed willy nilly, only certain ones are allowed by HTTP input)
+    #     * for legacy reasons, qt in http query does not over-ride qt in search field definition default. 
+    #  4.  extra parameters passed in as argument.
+    #
+    # spellcheck.q will be supplied with the [:q] value unless specifically
+    # specified otherwise. 
+    #
+    # Incoming parameter :f is mapped to :fq solr parameter.
+    def solr_search_params(user_params = params || {})
+      Blacklight::Solr::Request.new.tap do |solr_parameters|
+        solr_search_params_logic.each do |method_name|
+          send(method_name, solr_parameters, user_params)
+        end
+      end
+    end
+
+    ####
+    # Start with general defaults from BL config. Need to use custom
+    # merge to dup values, to avoid later mutating the original by mistake.
+    def default_solr_parameters(solr_parameters, user_params)
+      blacklight_config.default_solr_params.each do |key, value|
+        solr_parameters[key] = value.dup rescue value
+      end
+    end
+
+    ##
+    # Take the user-entered query, and put it in the solr params, 
+    # including config's "search field" params for current search field. 
+    # also include setting spellcheck.q. 
+    def add_query_to_solr(solr_parameters, user_parameters)
+      ###
+      # Merge in search field configured values, if present, over-writing general
+      # defaults
+      ###
+      # legacy behavior of user param :qt is passed through, but over-ridden
+      # by actual search field config if present. We might want to remove
+      # this legacy behavior at some point. It does not seem to be currently
+      # rspec'd. 
+      solr_parameters[:qt] = user_parameters[:qt] if user_parameters[:qt]
+
+      search_field_def = search_field_def_for_key(user_parameters[:search_field])
+      if (search_field_def)     
+        solr_parameters[:qt] = search_field_def.qt
+        solr_parameters.merge!( search_field_def.solr_parameters) if search_field_def.solr_parameters
+      end
+
+      ##
+      # Create Solr 'q' including the user-entered q, prefixed by any
+      # solr LocalParams in config, using solr LocalParams syntax. 
+      # http://wiki.apache.org/solr/LocalParams
+      ##         
+      if (search_field_def && hash = search_field_def.solr_local_parameters)
+        local_params = hash.collect do |key, val|
+          key.to_s + "=" + solr_param_quote(val, :quote => "'")
+        end.join(" ")
+        solr_parameters[:q] = "{!#{local_params}}#{user_parameters[:q]}"
+      else
+        solr_parameters[:q] = user_parameters[:q] if user_parameters[:q]
+      end
+
+
+      ##
+      # Set Solr spellcheck.q to be original user-entered query, without
+      # our local params, otherwise it'll try and spellcheck the local
+      # params! Unless spellcheck.q has already been set by someone,
+      # respect that.
+      #
+      # TODO: Change calling code to expect this as a symbol instead of
+      # a string, for consistency? :'spellcheck.q' is a symbol. Right now
+      # rspec tests for a string, and can't tell if other code may
+      # insist on a string. 
+      solr_parameters["spellcheck.q"] = user_parameters[:q] unless solr_parameters["spellcheck.q"]
+    end
+
+    ##
+    # Add any existing facet limits, stored in app-level HTTP query
+    # as :f, to solr as appropriate :fq query. 
+    def add_facet_fq_to_solr(solr_parameters, user_params)   
+
+      # convert a String value into an Array
+      if solr_parameters[:fq].is_a? String
+        solr_parameters[:fq] = [solr_parameters[:fq]]
+      end
+
+      # :fq, map from :f. 
+      if ( user_params[:f])
+        f_request_params = user_params[:f] 
+
+        f_request_params.each_pair do |facet_field, value_list|
+          Array(value_list).each do |value|
+            solr_parameters.append_filter_query facet_value_to_fq_string(facet_field, value)
+          end              
+        end      
+      end
+    end
+
+    ##
+    # Add appropriate Solr facetting directives in, including
+    # taking account of our facet paging/'more'.  This is not
+    # about solr 'fq', this is about solr facet.* params. 
+    def add_facetting_to_solr(solr_parameters, user_params)
+      # While not used by BL core behavior, legacy behavior seemed to be
+      # to accept incoming params as "facet.field" or "facets", and add them
+      # on to any existing facet.field sent to Solr. Legacy behavior seemed
+      # to be accepting these incoming params as arrays (in Rails URL with []
+      # on end), or single values. At least one of these is used by
+      # Stanford for "faux hieararchial facets". 
+      if user_params.has_key?("facet.field") || user_params.has_key?("facets")
+        solr_parameters[:"facet.field"].concat( [user_params["facet.field"], user_params["facets"]].flatten.compact ).uniq!
+      end                
+
+      blacklight_config.facet_fields.select { |field_name,facet|
+        facet.include_in_request || (facet.include_in_request.nil? && blacklight_config.add_facet_fields_to_solr_request)
+      }.each do |field_name, facet|
+        solr_parameters[:facet] ||= true
+
+        case 
+          when facet.pivot
+            solr_parameters.append_facet_pivot with_ex_local_param(facet.ex, facet.pivot.join(","))
+          when facet.query
+            solr_parameters.append_facet_query facet.query.map { |k, x| with_ex_local_param(facet.ex, x[:fq]) } 
+          else
+            solr_parameters.append_facet_fields with_ex_local_param(facet.ex, facet.field)
+        end
+
+        if facet.sort
+          solr_parameters[:"f.#{facet.field}.facet.sort"] = facet.sort
+        end
+
+        if facet.solr_params
+          facet.solr_params.each do |k, v|
+            solr_parameters[:"f.#{facet.field}.#{k}"] = v
+          end
+        end
+
+        # Support facet paging and 'more'
+        # links, by sending a facet.limit one more than what we
+        # want to page at, according to configured facet limits.
+        solr_parameters[:"f.#{facet.field}.facet.limit"] = (facet_limit_for(field_name) + 1) if facet_limit_for(field_name)
+      end
+    end
+
+    def add_solr_fields_to_query solr_parameters, user_parameters
+      blacklight_config.show_fields.select(&method(:should_add_to_solr)).each do |field_name, field|
+        if field.solr_params
+          field.solr_params.each do |k, v|
+            solr_parameters[:"f.#{field.field}.#{k}"] = v
+          end
+        end
+      end
+
+      blacklight_config.index_fields.select(&method(:should_add_to_solr)).each do |field_name, field|
+        if field.highlight
+          solr_parameters[:hl] = true
+          solr_parameters.append_highlight_field field.field
+        end
+
+        if field.solr_params
+          field.solr_params.each do |k, v|
+            solr_parameters[:"f.#{field.field}.#{k}"] = v
+          end
+        end
+      end
+    end
+
+    ###
+    # copy paging params from BL app over to solr, changing
+    # app level per_page and page to Solr rows and start. 
+    def add_paging_to_solr(solr_params, user_params)
+
+      # Now any over-rides from current URL?
+      solr_params[:rows] = user_params[:rows].to_i  unless user_params[:rows].blank?
+      solr_params[:rows] = user_params[:per_page].to_i  unless user_params[:per_page].blank?
+
+      # Do we need to translate :page to Solr :start?
+      unless user_params[:page].blank?
+        # already set solr_params["rows"] might not be the one we just set,
+        # could have been from app defaults too. But we need one.
+        # raising is consistent with prior RSolr magic keys behavior.
+        # We could change this to default to 10, or to raise on startup
+        # from config instead of at runtime.
+        if solr_params[:rows].blank?
+          raise Exception.new("To use pagination when no :per_page is supplied in the URL, :rows must be configured in blacklight_config default_solr_params")
+        end
+        solr_params[:start] = solr_params[:rows].to_i * (user_params[:page].to_i - 1)
+        solr_params[:start] = 0 if solr_params[:start].to_i < 0
+      end
+
+      solr_params[:rows] ||= blacklight_config.per_page.first unless blacklight_config.per_page.blank?
+
+      solr_params[:rows] = blacklight_config.max_per_page if solr_params[:rows].to_i > blacklight_config.max_per_page
+    end
+
+    ###
+    # copy sorting params from BL app over to solr
+    def add_sorting_to_solr(solr_parameters, user_params)
+      if user_params[:sort].blank? and sort_field = blacklight_config.default_sort_field
+        # no sort param provided, use default
+        solr_parameters[:sort] = sort_field.sort unless sort_field.sort.blank?
+      elsif sort_field = blacklight_config.sort_fields[user_params[:sort]]
+        # check for sort field key  
+        solr_parameters[:sort] = sort_field.sort unless sort_field.sort.blank?
+      else 
+        # just pass the key through
+        solr_parameters[:sort] = user_params[:sort]
+      end
+    end
+
+    # Remove the group parameter if we've faceted on the group field (e.g. for the full results for a group)
+    def add_group_config_to_solr solr_parameters, user_parameters
+      if user_parameters[:f] and user_parameters[:f][grouped_key_for_results]
+        solr_parameters[:group] = false
+      end
+    end
+
+    def with_ex_local_param(ex, value)
+      if ex
+        "{!ex=#{ex}}#{value}"
+      else
+        value
+      end
+    end
+
+    private
+
+    ##
+    # Convert a facet/value pair into a solr fq parameter
+    def facet_value_to_fq_string(facet_field, value) 
+      facet_config = blacklight_config.facet_fields[facet_field]
+
+      local_params = []
+      local_params << "tag=#{facet_config.tag}" if facet_config and facet_config.tag
+
+      prefix = ""
+      prefix = "{!#{local_params.join(" ")}}" unless local_params.empty?
+
+      fq = case
+        when (facet_config and facet_config.query)
+          facet_config.query[value][:fq]
+        when (facet_config and facet_config.date),
+             (value.is_a?(TrueClass) or value.is_a?(FalseClass) or value == 'true' or value == 'false'),
+             (value.is_a?(Integer) or (value.to_i.to_s == value if value.respond_to? :to_i)),
+             (value.is_a?(Float) or (value.to_f.to_s == value if value.respond_to? :to_f))
+             (value.is_a?(DateTime) or value.is_a?(Date) or value.is_a?(Time))
+          "#{prefix}#{facet_field}:#{value}"
+        when value.is_a?(Range)
+          "#{prefix}#{facet_field}:[#{value.first} TO #{value.last}]"
+        else
+          "{!raw f=#{facet_field}#{(" " + local_params.join(" ")) unless local_params.empty?}}#{value}"
+      end
+
+
+    end
+  end
+end