Ruby on Rails

Comments and changes to this ticket

• 

  Clemens July 10th, 2008 @ 02:07 PM

  • → Tag changed from “” to “2.1 activerecord bug to_xml”

  I think that's by design. As far as I see it, Rails converts a few types into "special" types and handles everything else as a string:

  # taken from ActiveSupport::CoreExtensions::Hash::Conversions
  XML_TYPE_NAMES = {
            "Symbol"     => "symbol",
            "Fixnum"     => "integer",
            "Bignum"     => "integer",
            "BigDecimal" => "decimal",
            "Float"      => "float",
            "Date"       => "date",
            "DateTime"   => "datetime",
            "Time"       => "datetime",
            "TrueClass"  => "boolean",
            "FalseClass" => "boolean"
          } unless defined?(XML_TYPE_NAMES)
  

  Everything that isn't in this hash will automatically be turned into a string. I guess you could just call serialize the method yourself (which is not very DRY). But I honestly don't know - I think I wouldn't expose associations like this but rather use the :include option.

  Just my 2 cents, of course.

• 

  Clemens July 10th, 2008 @ 02:09 PM

  Oops, didn't mean to change the tags - that just happened ... (but I guess it's right that way anyways)

• 

  Joran July 10th, 2008 @ 02:35 PM

  Hi Clemens, thanks for the comment. When it comes to type conversion, Rails certainly uses this to elegant effect in the JSON class.

  However, the problem is that this is not a design issue (as applied to type conversion or content types). It's a data issue.

  In other words, JSON and XML are merely data formats. The data itself should not change. In this case it does.

  Rails to_json gets it right (Ruby array -> Javascript array). Rails to_xml gets it wrong (Ruby array -> concatenated string). to_xml gets resource collection arrays right. I see no reason why it can't get this right.

  But regardless, it's a problem because :methods => other_ids is in the Rails docs and is supposed to be able to handle this. And to prove the point, the newly revamped Rails 2.1 to_json (which added :include and :methods support as far as I know) can handle this.

  So it's actually quite a discrepancy. To resolve it, we either need to force to_json to concatenate any :methods => other_ids arrays to strings as to_xml does (which would serve no utilitarian purpose). Or update to_xml to the level that to_json is at in this regard.

  Re: using :include vs :methods, I do use :include in other resources, but not for many-to-many resources where it makes more sense to use id references, as these kinds of relationships can often be of a more categorical/static/lookup nature.

  In any event, the nature of REST is atomicity (i.e. smaller, simpler, lighter, factorized resources that can be cached and combined more easily with others in different ways as opposed to large data clumps). :methods is far closer to this ideal than :include.

  It's important we get this fixed.