I am try to figure out how to properly validate a model collection whenever that collection is updated using the << collection operator. In our legacy app (Rails 3.2.1), I found that platform_collection_obj.platforms is updated using << operator
Example:
collection.platforms << new_platform
In researching how to validate that each platform in platforms collection has appropriate data, I found that I should use custom-validation function. So I tried adding each_platform_branch_id validation function to PlatformCollections Model. However, I found in testing (via rails console) that the validation was not triggered.
In reading Has-Many-Association-Collection Info, I came across this
Adds one or more objects to the collection by setting their foreign keys to the collection's primary key. Note that this operation instantly fires update SQL without waiting for the save or update call on the parent object, unless the parent object is a new record. This will also run validations and callbacks of associated object(s).
This excerpt indicates that using << to perform update on collection.platforms will not trigger the parent validations, which in this case would be the PlatformCollection:each_platform_branch_id validation function. I know that manually perforning collection.save would trigger validation, but it would be too late b/c << has already updated the DB.
So to restate the question is: How do I properly validate a has-many-through-model collection whenever that collection is updated using the << collection operator?
PlatformCollections Model
class PlatformCollection < ActiveRecord::Base
belongs_to :tezt
has_many :platform_collection_platforms, :order => "platform_collection_platforms.default DESC"
has_many :platforms, :through => :platform_collection_platforms, :order => "platform_collection_platforms.default DESC"
def each_platform_branch_id
platforms.each do |p|
if p.branch_id != @branch.id
err_msg = "Invalid Platform: #{p.to_json} for PlatformCollection: #{self.to_json}. " \
"Expected Branch: #{@branch.id}, Actual Branch: #{p.branch_id}"
errors.add(:platform, err_msg)
end
end
end
Platforms Model
class Platform < ActiveRecord::Base
attr_accessible :name
belongs_to :branch
has_many :platform_collection_platforms
has_many :platform_collections, :through => :platform_collection_platforms
