Nested forms with multiple models

rubyonrails-talk
1

Hey guys, I need your help again!

I have a form in which I want to nest multiple models. Kind of like "a project has many tasks" but rather "a flight has one flight time per flight type".

So it's three models - Flight, FlightType and FlightTime. Flight -> FlightTime <- FlightType

What I want to do is to loop through the FlightTypes in the add/edit Flight form, and present a text box whose value then will be stored as :hours in a FlightTime along with a :flight_id and :flight_type_id value. I hope I've made myself clear.

This is the code I have in my flight_form view currently:

http://pastie.org/312947

Now this works perfectly when _adding_ FlightTimes as I'm using a FlightTime.new, but the issue I have is that I also want to be able to edit the values. When I try to use this form for editing, all the values in the boxes are emptied and anything I put in them are added as new FlightTimes (obviously). There can only be one FlightTime per FlightType per Flight, so to speak.

So, anyone up for the task to help me out?

Thanks, Alex

2

one suggestion: don't put business logic in your views. replace "FlightTime.new" with "@flight_time" and let your controller figure out if it should be a new or existing record.

3

one suggestion: don't put business logic in your views. replace "FlightTime.new" with "@flight_time" and let your controller figure out if it should be a new or existing record.

...

> Now this works perfectly when _adding_ FlightTimes as I'm using a > FlightTime.new, but the issue I have is that I also want to be able to > edit the values. When I try to use this form for editing, all the > values in the boxes are emptied and anything I put in them are added > as new FlightTimes (obviously). There can only be one FlightTime per > FlightType per Flight, so to speak.

As per jemminger, if you want your action and template to both create new objects and edit existing ones you need to put this logic into the action in the controller.

So you might have:   if params[:id]     @foo=Foo.find(params[:id])   else     @foo=Foo.new   end

In your view, you can then get rails to put whatever values are currently in @foo into your fields:   form_for :foo , :url ... do |f|     f.text_field :field1     ...   end

or:   fields_for :foo do |f|     f.text_field :field1     ...   end

and rails will automagic in @foo.field1 as the value in that text field because you specified ':foo'. (Sorry, can't get my head around your models)

I was thinking that if you have an array of objects eg foo has_many bars and you want to edit all those bars, then in the view you could loop thru the array with an index eg:

  @foo.bars.each_with_index do |bar,idx|     fields_for "bars[#{idx}]" , bar do |b|       b.text_field :field1       ...     end     ...   end

Which, on submission, will generate   params['bars']['0']['field1'] => <some-value>   etc Not sure if that's good but I think it works. You could skip the whole 'with_index' thing if it's just has_one.

You'll also need to embed id value for each record into a hidden field in your form if you're editing an existing item so that you can find it and update it instead of creating a new object when the form is submitted. There are security implications here - people can post a random id instead - so you need to think that through carefully.