Question

I’ve got a relatively simple Rails app that takes a form with nested params that includes a photograph. It looks like this:

class List < ActiveRecord::Base
  has_many :list_items
  has_many :people, through: list_items
end

class ListItem < ActiveRecord::Base
  belongs_to :list
  belongs_to :person, autosave: true

  has_attached_file :picture,
    :storage => :s3,
    :bucket => 'myfreebielist',
    :s3_credentials => {
      :access_key_id => ENV['S3_KEY'],
      :secret_access_key => ENV['S3_SECRET']
    }


  def autosave_associated_records_for_person
    if new_person = Person.find_by_name(Person.name) then
      self.person = new_person
    else
      self.person.save!
    end
  end
end

class Person < ActiveRecord::Base
  has_many :list_items
end

I set up a test new form, just to make sure everything works, and it does, nice and pretty:

<%= form_for @list do |f| %>
  List name: <%= f.text_field :name %><br/>
  <%= f.fields_for :list_items do |lif| %>
    <%= lif.fields_for :person do |pif| %>
    Person name: <%= pif.text_field :name %>
    <% end %>
    Picture: <%= lif.file_field :picture %>
    <br/>
  <% end %>
  <%= f.submit %>
<% end %>

OK, so I want to be able to post a new list, with list items (and their related picture images), as well as the person for that list item. I have this code that I’m testing with in Objective C:

NSMutableDictionary *listParams = [NSMutableDictionary dictionary];
[listParams setValue:@"Test One" forKey:@"name"];

NSMutableDictionary *listItems = [NSMutableDictionary dictionary];

// Generate each list item -- a person and a photo.
NSDictionary *person1 = [NSDictionary dictionaryWithKeysAndObjects:@"name", @"John Smith", nil];
NSDictionary *listItem1 = [NSDictionary dictionaryWithKeysAndObjects:@"person_attributes", person1, nil];
[listItems setValue:listItem1 forKey:@"0"];
[listParams setValue:listItems forKey:@"list_items_attributes"];

NSMutableDictionary *params = [NSMutableDictionary dictionary];
[params setValue:listParams forKey:@"list"];

[[RKClient sharedClient] post:@"/lists" params:params delegate:self];

This also works fine, with the notable absence of the picture.

Now, I understand that using an RKParams instead of an NSDictionary is how you’re supposed to handle this type of request, but when I post using an RKParams there is all manner of strange things arriving at the rails side — lots of \n newlines, spaces and things around the keys. I tried using an RKParams with an attachment as part of person1, but it seems to just send the string representation of the name of the object RKParams object.

I feel like I’m so, so close but I’ve been hitting my head against this for hours now. Any help would be appreciated.

Environment: Xcode 4.3, Rails 3.2.1.

Answer 1

The answer is: JSON. I had to adjust the server to support JSON, something I should have done at the outset. That’s what all the spaces and \ns are about. Note to self: don’t program an all-nighter, no matter how motivated you are.