From: GFunk913@...
Date: 2006-07-28T14:35:06+09:00
Subject: Re: Mongoose 0.2.5 - The "Two Steps Forward, One Step Back" release


GFunk913@gmail.com wrote:
> Jamey Cribbs wrote:
> > GFunk913@gmail.com wrote:
> > > # Create new table.  Notice how you specify whether a column is indexed
> > > or not.
> > > db.create_table(:thing) do |tbl|
> > >   tbl.add_column(:foo,:dunno_what_to_put)
> > > end
> > >
> > > # Add a record.  You can also use #create.
> > > rec = Thing.new
> > > rec.foo = (1..100).to_a
> > > rec.save
> > >
> > > puts Thing.find.first.foo.size    #100
> > >
> > >
> > Logan already gave you one way to do this, and, probably from a purely
> > relational perspective, his suggestion is the right way to do it.
> >
> > Additionally, I know that ActiveRecord has the serialize class method
> > that you can use to have the object specified Marshaled into and out of
> > the db.  I am thinking of supporting that method, just because I want to
> > stay close to ActiveRecord's api.  The funny thing is, Mongoose
> > *already* Marhsals all of the data (that's how it stores the table
> > records).  Right now, I don't think I am doing much data checking in the
> > #save method, so you could probably get away with declaring the data
> > type as :string and then just going ahead and saving the array to
> > rec.foo like you are doing in the example.  It should work.
> >
> > Of course, in an upcoming version, I will make all of this work the way
> > it should, i.e. do more data type checking in #save and also give you
> > the ability to specify which columns you want to serialize.
> >
> > HTH,
> >
> > Jamey
>
> Yup, I understand i could relational-ize the array, it was a bad
> example.  Pretend i said an instance of some arbitrary Foo class
> instead of an array.  the point is I want to serialize arbitrary data,
> taking advantage of marshaling.
>
> I tried the :string method.  I get a dump format error when trying to
> read it back out of the found record.
>
> I'm familiar with  the serialize functionality in activerecord, that's
> the basic idea.  I think the problem is basically that the proper
> escaping for storing dump strings isn't being done.  I'll try and see
> if I can hack something in to make this work.

FYI, from what I can tell, at least for the array (1..9).to_a, writing
the marshal dump to mongoose and them reading it back makes 2 changes

1. adds a \r where the string contains a \n
2. removes a trailer \016 (shift out)

This is what causes the dump format error