_get_association (OpenID::Store::Filesystem)

    # File lib/openid/store/filesystem.rb, line 100
          def _get_association(filename)
            begin
              assoc_file = File.open(filename, "r")
            rescue Errno::ENOENT
              return nil
            else
              begin
                assoc_s = assoc_file.read
              ensure
                assoc_file.close
              end

              begin
                association = Association.deserialize(assoc_s)
              rescue
                self.remove_if_present(filename)
                return nil
              end

              # clean up expired associations
              if association.expires_in == 0
                self.remove_if_present(filename)
                return nil
              else
                return association
              end
            end
          end