Creating/Updating Models from text/xml Requests


#1

I’m curious how others would deal with this situation.

In my case, I have:

class Package
has_many :deliveries
end

class Delivery
belongs_to :package
belongs_to :region
end

class Region
has_many :deliveries
end

And accept XML requests in the following manner:

Good Shipment Failure US Unknown FR

Now, my controller would look something like this ugly beast:

class PackagesController
def create
if package = params[:package]
package = Package.find_or_initialize_by_name(package)
if deliveries = package.delete(:deliveries)
deliveries.each do |d|
region = d.delete(:region)
region = Region.find_or_create_by_name(region[:name])
break if region.nil?
package.deliveries.create(region)
package.deliveries[-1].region = region
end
end
end
#save and more…
end
end

As one can see, this is horrible for several reasons. One of the big
ones being request validation and error handling.

Overriding package.from_xml is an option, but I find myself thinking
that I should be validating against request.body with say a DTD, as
opposed to picking apart the params hash. (Though I’ll have to pick it
apart anyways to create the models…)

Then I find my self thinking that creating a course grained validation
method like a DTD is stupid since I have my fine grain validation
logic within the given models.

Yes, I’ve heard of ROXML.

Any thoughts?


#2

MaggotChild wrote:

And accept XML requests in the following manner:

Good Shipment Failure

If you try this from_xml…

http://gist.github.com/75525

…I think it would clear the make-work out of the way, allowing you to
focus on
the validations. Tell me if you get stuck - I wrote it for your exact
situation,
but it can’t validate automatically.