Ruby on Rails multiple images connected to one object - ruby-on-rails

Question

I've been trying to create a form that would get parameters for multiple models. I have a photo model that belongs to a product model and I want to make it so that when you create a new product you can also upload images that are linked to that product by id.
<%= form_for #product, html:{multipart:true} do |f| %>
<div class="field">
<%= f.label :price %>
<%= f.text_field :price %>
</div>
<%=form_for #photo do |t| %>
<%t.productID = f.id%>
<div class="field">
<%= t.label (:image) %>
<%= t.file_field (:image) %>
</div>
<%end%>
<div class="actions">
<%= f.submit %>
</div>
<%end%>
right now I'm using paperclip for image attachments and the photo model accepts the images as parameters. I've used paperclip before but the product could only have one image connected to it. If I use the form above I get "First argument in form cannot contain nil or be empty" error and it points to where the form_for #photo starts.I have controllers for both with the usual methods of new, create, update, etc. I've routed resources to both product and photos but I'm still pretty new to rails and don't fully understand how this stuff works.

Answer 1

I think what you're trying to do is a good application for nested forms using the fields_for helper.
First, you'll need to ensure that your product model and photo model have the right associations (A product probably has_many photos, and a photo belongs to a product, right?). Then you'll make sure the product class 'accepts nested attributes for photo's which allows you to add attributes to the photos model from a products form.
in products.rb
class Product
has_many :photos
accepts_nested_attributes_for :photos
end
and in photo.rb
class Photo
belongs_to :product
end
Then you'll want to make sure any attributes you need for the photo are white-listed in your product params.
in products_controller.rb
private
def product_params
params.require(product).permit(:first_product_attribute, :second_produtc_attribute, photo_attributes: [:image])
end
Last, you'll create the form using the special helper fields_for
in your view
<%= form_for #product, html:{multipart:true} do |f| %>
<div class="field">
<%= f.label :price %>
<%= f.text_field :price %>
</div>
<%= f.fields_for :photo do |t| %>
<div>
<%= t.label :image %>
<%= t.file_field :image, :multiple => true %>
</div>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<%end%>
You'll also need to make sure you're actually creating new photo objects in your product's create action:
in products_controller.rb
def create
#product = Product.new(product_params)
if #product.save!
params[:photo]['image'].each do |img|
#photo = #product.photos.create!(:image => img)
end
flash[:success] = 'product saved!'
redirect_to #product
end
end
Some of this is based on my experience doing the same thing but with Carrierwave instead of Paperclip so your specific implementation might be a little different.

Answer 2

I dont think this is a proper method <%t.productID = f.id%>. Maybe try <% t.text_field :productID, value = f.id, type = hidden %> or something along those lines?
heres some docs for the form helper so you know what to put after t.abcd
http://apidock.com/rails/v3.2.3/ActionView/Helpers/FormHelper/form_for

Answer 3

You're getting the
"First argument in form cannot contain nil or be empty"
..error because #photo is nil, you need to set it in your controller #photo = Photo.new.
Also, form tags inside form tags are invalid HTML.
https://www.w3.org/TR/html5/forms.html#the-form-element
Forms
Content model: Flow content, but with no form element
descendants.
You want to use f.fields_for instead. Learn how to use it here here
I have controllers for both with the usual methods of new, create,
update, etc.
You only ever hit one controller and action when you go to a path, say /photos will only hit the photos controller (as configured in your routes.rb). This I think is where you're messing up the #photo variable. Set both in the same controller in order for the view to be able to see both variables.