Forum: Ruby on Rails to_xml associations and :only

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Marcelo B. (Guest)
on 2008-10-28 17:17
(Received via mailing list)

A call to to_xml(:only => [:field], :include => :association]) will
filter the association result too(the resulting association will only
have :field).

Is there a way around this?

I want to specify different filters for the main object and the

Robert Z. (Guest)
on 2008-10-29 20:00
(Received via mailing list)

Unfortunately like you mentioned when you use the :only options it
will filter through all the associations as well. You can get around
this by passing a proc to_xml that appends the associations to the
builder. For example we will take the ever so popular example of a
User having many Posts.

class User
  has_many :posts

class Post
  belongs_to :user

user    = User.first
posts  = user.posts
post_proc = lambda do |options|
  options[:builder] << posts.to_xml(:skip_instruct => true)

user.to_xml(:only => :first_name, :procs => post_proc)

Make sure you have the :skip_instruct => true option when you are
creating the xml for your associations so it does not add the XML
declaration <?xml version="1.0 ... >


Robert Z.
Zapient, LLC
Ruby on Rails Development and Consulting
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