Question

I have found several websites pointing to using the following code to add support for custom parameter formats:

ActionController::Base.param_parsers[Mime::PLIST] = lambda do |body|
  str = StringIO.new(body)
  plist = CFPropertyList::List.new({:data => str.string})
  CFPropertyList.native_types(plist.value)
end

This one here is for the Apple plist format, which is what I am looking to do. However, using Rails 3.2.1, The dev server won’t start, saying that param_parsers is undefined. I cannot seam to find any documentation for it being deprecated or any alternative to use, just that it is indeed included in the 2.x documentation and not the 3.x documentation.

Is there any other way in Rails 3 to support custom parameter formats in POST and PUT requests?

Answer 1

The params parsing moved to a Rack middleware. It is now part of ActionDispatch.

To register new parsers, you can either redeclare the use of the middleware like so:

MyRailsApp::Application.config.middleware.delete "ActionDispatch::ParamsParser"
MyRailsApp::Application.config.middleware.use(ActionDispatch::ParamsParser, {
  Mime::PLIST => lambda do |body|
    str = StringIO.new(body)
    plist = CFPropertyList::List.new({:data => str.string})
    CFPropertyList.native_types(plist.value)
  end
})

or you can change the constant containing the default parsers like so

ActionDispatch::ParamsParser::DEFAULT_PARSERS[Mime::PLIST] = lambda do |body|
  str = StringIO.new(body)
  plist = CFPropertyList::List.new({:data => str.string})
  CFPropertyList.native_types(plist.value)
end

The first variant is probably the cleanest. But you need to be aware that the last one to replace the middleware declaration wins there.