Implement same functionality using temporary functions in the pg_temp…

… namespace and do away with needing a custom variable. Fixes #1

README.rdoc

@@ -13,19 +13,11 @@ Compatible with Rails 3.0.x and 3.1.x
 
 == INSTALL
 
-=== Enable custom variables in your postgresql instance
+=== Enable plpgsql langauges in your postgresql instance
 
-  To enable auditing you need to set a variable in your postgresql.conf file:
+  As a superuser in postgres make sure your database has plpgsql enabled:
 
-  For macports: /opt/local/var/db/postgresql84/defaultdb/postgresql.conf
-  For homebrew: /usr/local/var/postgres/postgresql.conf
-  For linux: it varies from distro to distro.
-
-  At the bottom of the file add the following:
-
-    custom_variable_classes = 'audit'
-
-  Then restart your PostgreSQL server
+  CREATE OR REPLACE PROCEDURAL LANGUAGE plpgsql;
 
 === Rails 3
 

lib/pg_audit_log/extensions/3.0/postgresql_adapter.rb

@@ -3,11 +3,9 @@
 # Did not want to reopen the class but sending an include seemingly is not working.
 class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
   def execute_with_auditing(sql, name = nil)
-    current_user = Thread.current[:current_user]
-    user_unique_name = current_user.try(:unique_name) || "UNKNOWN"
-
-    log_user_id = %[SET audit.user_id = #{current_user.try(:id) || "-1"}]
-    log_user_unique_name = %[SET audit.user_unique_name = "#{user_unique_name}"]
+    user_id, unique_name = user_id_and_name
+    log_user_id = PgAuditLog::Function.user_identifier_temporary_function(user_id)
+    log_user_unique_name = PgAuditLog::Function.user_unique_name_temporary_function(unique_name)
 
     log([log_user_id, log_user_unique_name, sql].join("; "), name) do
       if @async

lib/pg_audit_log/extensions/3.1/postgresql_adapter.rb

@@ -3,11 +3,9 @@
 # Did not want to reopen the class but sending an include seemingly is not working.
 class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
   def generate_auditing_sql(sql)
-    current_user = Thread.current[:current_user]
-    user_unique_name = current_user.try(:unique_name) || "UNKNOWN"
-
-    log_user_id = %[SET audit.user_id = #{current_user.try(:id) || "-1"}]
-    log_user_unique_name = %[SET audit.user_unique_name = "#{user_unique_name}"]
+    user_id, unique_name = user_id_and_name
+    log_user_id = PgAuditLog::Function.user_identifier_temporary_function(user_id)
+    log_user_unique_name = PgAuditLog::Function.user_unique_name_temporary_function(unique_name)
     { :user_id => log_user_id, :unique_name => log_user_unique_name, :sql => sql }
   end
 

lib/pg_audit_log/extensions/shared/postgresql_adapter.rb

@@ -56,4 +56,13 @@ def rename_table_with_auditing(table_name, new_name)
   end
   alias_method_chain :rename_table, :auditing
 
+  private
+
+  def user_id_and_name
+    current_user = Thread.current[:current_user]
+    user_id = current_user.try(:id) || "-1"
+    user_unique_name = current_user.try(:unique_name) || "UNKNOWN"
+    return [user_id, user_unique_name]
+  end
+
 end

lib/pg_audit_log/function.rb

@@ -5,10 +5,6 @@ def name
         "audit_changes"
       end
 
-      def custom_variable
-        "audit"
-      end
-
       def users_table_name
         "users"
       end
@@ -25,6 +21,30 @@ def users_access_column
         "last_accessed_at"
       end
 
+      def user_identifier_temporary_function(user_id)
+        sql = <<-SQL
+          CREATE OR REPLACE FUNCTION pg_temp.pg_audit_log_user_identifier() RETURNS integer
+          LANGUAGE plpgsql
+          AS $_$
+            BEGIN
+              RETURN #{user_id};
+            END
+            $_$;
+        SQL
+      end
+
+      def user_unique_name_temporary_function(username)
+        sql = <<-SQL
+          CREATE OR REPLACE FUNCTION pg_temp.pg_audit_log_user_unique_name() RETURNS varchar
+          LANGUAGE plpgsql
+          AS $_$
+            BEGIN
+              RETURN '#{username}';
+            END
+            $_$;
+        SQL
+      end
+
       def install
         execute <<-SQL
         CREATE OR REPLACE PROCEDURAL LANGUAGE plpgsql;
@@ -46,8 +66,8 @@ def install
                 old_value := NULL;
                 primary_key_column := NULL;
                 primary_key_value := NULL;
-                user_identifier := current_setting('#{custom_variable}.#{user_id_field}');
-                unique_name := current_setting('#{custom_variable}.#{user_name_field}');
+                user_identifier := pg_temp.pg_audit_log_user_identifier();
+                unique_name := pg_temp.pg_audit_log_user_unique_name();
                 column_name := col.column_name;
 
                 EXECUTE 'SELECT pg_attribute.attname

lib/pg_audit_log/version.rb

@@ -1,3 +1,3 @@
 module PgAuditLog
-  VERSION = "0.3.6"
+  VERSION = "0.4.0"
 end

spec/configuration_spec.rb

@@ -5,14 +5,8 @@
     ActiveRecord::Base.connection.reconnect!
   end
 
-  it "allows custom class variables for audit" do
-    lambda {
-      ActiveRecord::Base.connection.execute('SET audit.test = 1')
-    }.should_not raise_error(ActiveRecord::StatementInvalid), "Your postgres is not configured for auditing. See README.rdoc"
-  end
-
   it "has an audit log table" do
     ActiveRecord::Base.connection.table_exists?("audit_log").should be_true
   end
 
-end
+end