This is a pain and took me about an hour to figure out today.<\/p>\n
Rails ActiveRecord instances offer a nice function to render xml:<\/p>\n
my_model.to_xml()<\/pre>\nThis method can be fed with a parameter <\/p>\n
:include => []<\/pre>\nto have all associations being integrated in the XML tree, just like when calling<\/p>\n
my_model = MyModel.find( :include => [association])<\/pre>\nBut when I tried to use it, it always failed when dealing with nested associations. Until I found out the trick.
\nThis is how it works: Basically you need to build a list of nested hashes.<\/p>\nclass Book < ActiveRecord::Base\r\n has_many :pages\r\n has_one :owner\r\nend<\/pre>\nclass Owner < ActiveRecord::Base\r\n has_many :books\r\nend<\/pre>\nclass Page < ActiveRecord::Base\r\n has_many :spots_of_coffees\r\n belongs_to :book\r\nend<\/pre>\nclass SpotOfCoffee < ActiveRecord::Base\r\n belongs_to :page\r\nend<\/pre>\nNow, you want to create a nice XML output containing a book, with its owner, pages and all spots of coffee?
\nPretty easy:<\/p>\n\r\n @book = Book.first\r\n includes = {} # let's build a hash; it's easier to read. At least for me...\r\n includes[:owner] = {} # owner has no association. So, let's take an empty hash as target\r\n includes[:pages] = { :include => :spots_of_coffee } #load pages and include its spots of coffee\r\n \r\n respond_to do |format|\r\n format.xml { render :text => @book.to_xml(:include => includes) }\r\n end\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"This is a pain and took me about an hour to figure out today. Rails ActiveRecord instances offer a nice function to render xml: my_model.to_xml() This method can be fed with a parameter :include => [] to have all associations being integrated in the XML tree, just like when calling my_model = MyModel.find( :include => … <\/p>\n