Rails - Jul 2006 - Serialized object behaves weird

Hi!

I got a class named EinsatzFilter which I serialized to session. Before 
saving to session it works afterwards I keep getting the message: 
"undefined method `to_s'' for #<Person:0x38c6ab8>".
"Person" is a from
ActiveRecord::Base inherited class.

Code:

class EinsatzFilter
  include ApplicationHelper

  attr_reader :personen, :monat, :projekte, :kunde
  attr_writer :personen, :monat, :projekte, :kunde

  ATTRIBUTES = [
    [''personen'', ''person_id'',
''Personen'', Person],
    [''projekte'', ''projekt_id'',
''Projekte'', Projekt],
  ]

  def initialize(attrs = nil)
    attrs.each {|k,v| self.send(k + ''='', v) } unless
attrs.nil?
  end

  def to_s
    ret = String.new
    ATTRIBUTES.each {|attr|
      vals = self.send(attr[0])
      ret << (ret.empty? ? "" : "; ") + attr[2] +
": " + \
        make_list(vals.collect{|val| val.to_i },attr[3]) unless 
vals.nil?
    }
    ret
  end

  # Erzeugt aus dem Filter ein Array zur ?bergabe als :condition an
  # ActiveRecord::Base.find.
  # R?ckgabewert k?nnte z.B. sein:
  # ["person_id in (?) and projekt_id in (?)", [2, 3], [1, 2, 3]]
  #
  # :call-seq:
  #   find(:Einsatz, :conditions => @einsatz_filter.conditions)
  #
  def conditions
    ret = Array.new(1, '''')
    attrs = ATTRIBUTES.collect {|attr|
      attr = [self.send(attr[0]), attr[1]]
    }
    attrs.each {|obj|
      unless obj[0].nil?
        ret[0] << " and " unless ret[0].empty?
        ret[0] << "#{obj[1]} in (?)"
        ret << obj[0].collect{|x| x.to_i}
      end
    }
    return ret unless ret.length == 1
  end

private
  def make_list(arr, obj)
    ret = ''''
    obj.find(arr).each {|p|
      ret << '', '' unless ret.length == 0
      ret << p.to_s
    }
    ret
  end
end


class Person < ActiveRecord::Base
  has_many :Einsatz

  def to_s
    self.name
  end
end



What''s my problem?


Greetings,
Alex.

-- 
Posted via http://www.ruby-forum.com/.

If I ask before this exception appears I get the following array 
including "to_s":

"require_gem_with_options", "after_find",
"cattr_accessor", "const_set",
"delete_observers", "parents", "read_methods",
"extend",
"encode_quoted_value", "validates_numericality_of",
"l_has_string?",
"construct_calculation_sql", "active_connection_name", 
"set_readonly_option!", "after_update",
"set_inheritance_column",
"deprecated_has_association_method", "sum",
"serialize", "frozen?",
"pluralize_table_names", "has_many",
"count_observers", "to_a",
"delete_all", "extended_by",
"pluralize_table_names=",
"before_validation", "set_language", 
"deprecated_association_comparison_method", 
"thread_safe_scoped_methods", "connected?",
"lock_optimistically",
"const_defined?", "l_time", "validate_on_create",
"is_complex_yaml?",
"has_and_belongs_to_many", "lock_optimistically=",
"as_load_path",
"reset_column_information_and_inheritable_attributes_for_all_subclasses",
"unlock_mutex", "class_inheritable_reader",
"sqlite3_connection",
"destroy", "table_exists?", "to_s",
"nil?",
"copy_instance_variables_from",
"clear_active_connection_name",
"to_yaml_properties", "after_validation",
"included_modules",
"single_threaded_scoped_methods", "respond_to?",
"set_locking_column",
"current_scoped_methods", "serialized_attributes",
"colorize_logging",
"scope", "validate_on_update", "create!",
"postgresql_connection",
"human_attribute_name", "class_inheritable_writer",
"const_missing",
"has_one", "inspect", "update_all",
"equal?", "load",
"colorize_logging=", "reflect_on_aggregation",
"set_language_if_valid",
"reset_column_information", "find_on_conditions", 
"before_validation_on_create", "find_by_sql",
"reset_locking_column",
"remove_subclasses", "reset_table_name",
"l_YesNo",
"class_inheritable_array_writer", "class_variables",
"belongs_to",
"methods", "daemonize", "include?",
"timestamps_gmt", "eql?", "require",
"retrieve_connection", "method_defined?",
"columns", "name",
"after_validation_on_create", "acts_as_tree",
"hash", "calculate",
"validates_size_of", "timestamps_gmt=",
"remove_subclasses_of",
"scoped_methods", "condition_block?", "find", 
"deprecated_find_in_collection_method", "changed?",
"method",
"default_timezone", "evaluate_condition",
"to_yaml",
"class_inheritable_hash_writer", "create_reflection", 
"silence_warnings", "singleton_methods",
"display", "logger",
"default_timezone=", "compute_type", "autoload", 
"public_method_defined?", "ancestors",
"before_validation_on_update",
"id", "db2_connection", "connection",
"class_name",
"class_name_of_active_record_descendant",
"validates_uniqueness_of",
"exists?", "average", "with_exclusive_scope",
"subclasses",
"verification_timeout", "logger=", "base_class", 
"descends_from_active_record?", 
"deprecated_find_all_in_collection_method", "connection=", 
"validates_each", "sanitize",
"class_inheritable_accessor",
"verification_timeout=", "superclass",
"clear_active_connections!",
"protected_methods", "destroy_all",
"openbase_connection",
"acts_as_list", "extend_with_included_modules_from", 
"private_method_defined?", "after_validation_on_update", 
"firebird_connection", "__id__",
"replace_named_bind_variables",
"subclasses_of", "find_all", "set_table_name", 
"deprecated_collection_create_method", "l_yesno",
"allow_concurrency",
"benchmark", "autoload?",
"class_inheritable_array", "private_methods",
"enable_warnings", "count_by_sql",
"instance_values", "<=>",
"protected_method_defined?", "reset_subclasses",
"allow_concurrency=",
"==", "before_destroy", "included_in_classes",
"object_id",
"transaction", "table_name", "<",
"===", "replace_bind_variables",
"public_class_method", "sanitize_sql",
"threaded_connections",
"remove_class", "sqlserver_connection",
"observers=", ">", ">=",
"deprecated_collection_build_method", "reset_primary_key", 
"table_name=", "<=", "instance_method",
"threaded_connections=",
"class_inheritable_hash", "verify_active_connections!",
"delete",
"public_methods", "silence_stderr",
"sanitize_conditions", "=~",
"instance_exec", "l_age", "after_destroy",
"columns_hash", "type",
"private_class_method", "class_of_active_record_descendant",
"current_language", "create", "encode64",
"validates_confirmation_of",
"rails_original_const_missing", "generate_read_methods",
"allocate",
"inheritable_attributes", "composed_of",
"instance_variables",
"silence_stream", "sqlite_connection",
"configurations",
"generate_read_methods=", "validate", "class",
"module_eval",
"instantiate", "raise_if_bind_arity_mismatch",
"parent",
"thread_safe_active_connections", "configurations=",
"abstract_class",
"ll", "set_primary_key", "l_lang_name",
"count", "abstract_class=",
"instance_variable_get", "blank?",
"increment_counter", "returning",
"acts_as_nested_set", "mattr_reader",
"column_names",
"instance_methods", "clone", "decode_b",
"class_eval",
"deprecated_collection_count_method", "validates_format_of",
"single_threaded_active_connections", "ltry",
"inheritance_column",
"update", "after_initialize", "decode64",
"schema_format", "inherited",
"reflections", "write_inheritable_attribute",
"instance_variable_set",
"inheritance_column=", "__send__", "with_options",
"l_date",
"primary_key_prefix_type", "schema_format=",
"mattr_writer",
"abstract_class?", "public_instance_methods",
"dup",
"deprecated_add_association_relation", "primary_key", 
"quote_bound_value", "primary_key_prefix_type=",
"active_connections",
"sequence_name", "new", "before_save",
"primary_key=",
"validates_acceptance_of", "`",
"class_inheritable_option",
"write_inheritable_array", "reflect_on_all_aggregations",
"suppress",
"oracle_connection", "decrement_counter",
"sequence_name=",
"l_strftime", "content_columns",
"protected_instance_methods",
"changed", "mattr_accessor", "taint", 
"deprecated_remove_association_relation",
"validates_inclusion_of",
"reset_sequence_name", "after_save", "lwr",
"send", "find_first",
"with_scope", "mysql_connection",
"attr_protected",
"connection_without_query_cache=",
"instantiate_with_callbacks",
"to_json", "table_name_prefix", "require_gem",
"lock_mutex",
"cattr_reader", "private_instance_methods",
"notify_observers",
"delegate", "to_yaml_type",
"validates_exclusion_of",
"record_timestamps", "reloadable?",
"deprecated_has_collection_method",
"table_name_prefix=", "before_create", "lwr_",
"instance_of?",
"instance_eval", "validates_presence_of",
"record_timestamps=",
"read_inheritable_attribute", "reflect_on_all_associations",
"locking_column", "protected_attributes",
"tainted?", "scoped?",
"establish_connection", "l_datetime",
"column_methods_hash",
"constants", "quote", "untaint",
"b64encode", "validates_associated",
"execute_grouped_calculation", "extract_options_from_args!",
"set_sequence_name", "after_create", "kind_of?",
"method_added",
"validates_length_of", "validate_find_options", 
"write_inheritable_hash", "l", "oci_connection",
"attr_accessible",
"minimum", "table_name_suffix", "add_observer",
"cattr_writer",
"const_get", "reflect_on_association",
"delete_observer", "freeze",
"execute_simple_calculation", "log_connections",
"table_name_suffix=",
"silence", "before_update", "is_a?",
"reset_inheritable_attributes",
"require_library_or_gem", "accessible_attributes",
"maximum",
"remove_connection", "l_datetime_short"

-- 
Posted via http://www.ruby-forum.com/.

I wrote:
>   def make_list(arr, obj)
>     ret = ''''
>     obj.find(arr).each {|p|
>       ret << '', '' unless ret.length == 0
>       ret << p.to_s
>     }
>     ret
>   end
> end

I finally got it, but I am not clearly about the problem. I had to 
change "obj.find" to "eval(obj).find".

Please could someone explain that to me?


Alex.

-- 
Posted via http://www.ruby-forum.com/.