When I create a table with the following SQL: # create table foos (id SERIAL, content VARCHAR(255)); And define a class as follows: class Foo < ActiveRecord::Base serialize :content, JSON end Creating a new instance of the class gives an error:> f = Foo.newNoMethodError: undefined method `read'' for nil:NilClass from /Users/andy/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.0/lib/active_support/whiny_nil.rb:48:in `method_missing'' from /Users/andy/Code/FakePlatform/vendor/gems/Darwin/gems/json-1.4.6/lib/json/common.rb:286:in `load'' from /Users/andy/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/base.rb:1938:in `block in set_serialized_attributes'' Does anyone have any ideas how to fix this? It should work (it''s such a simple case). Cheers, Andy -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Oct 6, 11:02 am, Andy Jeffries <a...-4Fjv1yF9AWJvmwGHilWZ5bVCufUGDwFn@public.gmane.org> wrote:> When I create a table with the following SQL: > > # create table foos (id SERIAL, content VARCHAR(255)); > > And define a class as follows: > > class Foo < ActiveRecord::Base > serialize :content, JSON > endthe second argument to serialise is used to say that you always want the serialised object to be of a certain class (e.g. Hash, an application specific class etc.). I''m not sure what you meant by passing JSON as that argument but I suspect that it isn''t doing what you think it is. Fred> > Creating a new instance of the class gives an error: > > > f = Foo.new > > NoMethodError: undefined method `read'' for nil:NilClass > from /Users/andy/.rvm/gems/ruby-1.9.2-p290/gems/activesupport-3.1.0/lib/active_s upport/whiny_nil.rb:48:in `method_missing'' > from /Users/andy/Code/FakePlatform/vendor/gems/Darwin/gems/json-1.4.6/lib/json/c ommon.rb:286:in `load'' > from /Users/andy/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_re cord/base.rb:1938:in `block in set_serialized_attributes'' > > Does anyone have any ideas how to fix this? > > It should work (it''s such a simple case). > > Cheers, > > Andy-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
> the second argument to serialise is used to say that you always want > the serialised object to be of a certain class (e.g. Hash, an > application specific class etc.). I''m not sure what you meant by > passing JSON as that argument but I suspect that it isn''t doing what > you think it is.I was basing it on this article (as well as a stack overflow answer) that you can provide a custom serializer in Rails 3.1: http://edgerails.info/articles/what-s-new-in-edge-rails/2011/03/09/custom-activerecord-attribute-serialization/index.html JSON provides a dump and load method on the class so it should be acceptable as the serializer. Is this article incorrect or my understanding of it? Cheers, Andy -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
> I was basing it on this article (as well as a stack overflow answer) that you can provide a custom serializer in Rails 3.1: > > http://edgerails.info/articles/what-s-new-in-edge-rails/2011/03/09/custom-activerecord-attribute-serialization/index.html > > JSON provides a dump and load method on the class so it should be acceptable as the serializer. > > Is this article incorrect or my understanding of it?Having just had a read of ActiveRecord::Base, I still can''t see how I go wrong… Base#serialize (line 557 of base.rb in ActiveRecord 3.1.0) if the object supplied as the second argument responds to :load and :dump (which JSON does), then it uses that object, if not it wraps it in a YAMLColumn and sets the entry in serialized_attributes to that object. Then in: Base#arel_attributes_values (line 1963 of base.rb in ActiveRecord 3.1.0) if there is an entry in serialized_attributes for a given attribute name (with a value put in to the coder variable) it calls coder.dump with the attribute value. So, I can''t understand why JSON wouldn''t work as a second parameter... Cheers, Andy -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
You''re using the syntax of serialize properly.
The problem looks like it''s in the JSON.load method not properly
handling a
nil value:
def load(source, proc = nil)
if source.respond_to? :to_str
source = source.to_str
elsif source.respond_to? :to_io
source = source.to_io.read
else
source = source.read
end
result = parse(source, :max_nesting => false, :allow_nan => true)
recurse_proc(result, &proc) if proc
result
end
Basically it gets to the line "source = source.read" and throws up
because
source is nil and nil doesn''t have a read method.
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I''ve also just tried upgrading JSON to 1.6.0 (as that''s the version that seems to be installed if I do gem install json), same problem. Cheers, Andy -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.