ActiveRecordWrapper works with custom identifier_field

With limited test.

Author: jrochkind

lib/oai/provider/model/activerecord_wrapper.rb

@@ -10,11 +10,18 @@ module OAI::Provider
   #
   class ActiveRecordWrapper < Model
 
-    attr_reader :model, :timestamp_field
-
+    attr_reader :model, :timestamp_field, :identifier_field
+
+    # If custom 'timestamp_field' is used, be aware this will be an ActiveRecord
+    # attribute that we will limit on, so perhaps should be indexe appropriately.
+    #
+    # If custom `identifier_field` is used, be aware this will be an ActiveRecord
+    # attribute that we will sort on, and use in WHERE clauses with `=` as well as
+    # greater than/less than, so should be indexed appropriately.
     def initialize(model, options={})
       @model = model
       @timestamp_field = options.delete(:timestamp_field) || 'updated_at'
+      @identifier_field = options.delete(:identifier_field) || model.primary_key || "id"
       @limit = options.delete(:limit) || 100
 
       unless options.empty?
@@ -54,7 +61,7 @@ def find(selector, options={})
           find_scope.where(conditions)
         end
       else
-        find_scope.where(conditions).find(selector)
+        find_scope.where(conditions).find_by!(identifier_field => selector)
       end
     end
 
@@ -129,7 +136,7 @@ def next_set(find_scope, token_string)
       else # end of result set
         find_scope.where(token_conditions(token))
           .limit(@limit)
-          .order("#{model.primary_key} asc")
+          .order("#{identifier_field} asc")
       end
     end
 
@@ -138,9 +145,9 @@ def next_set(find_scope, token_string)
     def select_partial(find_scope, token)
       records = find_scope.where(token_conditions(token))
         .limit(@limit)
-        .order("#{model.primary_key} asc")
+        .order("#{identifier_field} asc")
       raise OAI::ResumptionTokenException.new unless records
-      offset = records.last.send(model.primary_key.to_sym)
+      offset = records.last.send(identifier_field)
 
       PartialResult.new(records, token.next(offset))
     end
@@ -157,7 +164,7 @@ def token_conditions(token)
 
       return sql if 0 == last
       # Now add last id constraint
-      sql.first << " AND #{model.primary_key} > :id"
+      sql.first << " AND #{identifier_field} > :id"
       sql.last[:id] = last
 
       return sql

test/activerecord_provider/helpers/providers.rb

@@ -12,6 +12,13 @@ class ARProvider < OAI::Provider::Base
   source_model ActiveRecordWrapper.new(DCField)
 end
 
+class ARProviderCustomIdentifierField < OAI::Provider::Base
+  repository_name 'ActiveRecord Based Provider'
+  repository_url 'http://localhost'
+  record_prefix 'oai:test'
+  source_model ActiveRecordWrapper.new(DCField, identifier_field: "source")
+end
+
 class ARProviderWithScope < OAI::Provider::Base
   DATE_LESS_THAN_RESTRICTION = Time.parse("2007-03-12 19:30:22 UTC")
 

test/activerecord_provider/tc_ar_provider.rb

@@ -40,6 +40,18 @@ def test_list_records_scope
     assert_equal expected_count, doc.elements['OAI-PMH/ListRecords'].to_a.size
   end
 
+
+  def test_get_record_alternate_identifier_column
+    @provider = ARProviderCustomIdentifierField.new
+
+    record_id = DCField.first.send(@provider.class.model.identifier_field)
+
+    doc = REXML::Document.new(@provider.get_record(
+        :identifier => "oai:test:#{record_id}", :metadata_prefix => 'oai_dc'))
+
+    assert_equal "oai:test:#{record_id}", doc.elements['OAI-PMH/GetRecord/record/header/identifier'].text
+  end
+
   def test_list_identifiers
     assert_nothing_raised { REXML::Document.new(@provider.list_identifiers) }
     doc = REXML::Document.new(@provider.list_identifiers)