Rails 4 Strong Parameters Nested Resource

Question

I have a nested resource like the following: user/1/photos/new

resources :users, only: [] do
  resources :photos, except: [:show]
end

My form_for is like the following:

= form_for([@user, @photo], html: { multipart: true }) do |f|

  .inputs
    = f.file_field :attached_photo

  .actions
    = f.submit :submit

I believe the problem I am having is with strong parameters:

   def photo_params
      params.require(:photo).permit(:title, :attached_photo)
    end

When I hit the submit button on the form I get the following error:

ActionController::ParameterMissing in PhotosController#create param not found: photo

I'm using Paperclip so in the model I have:

has_attached_file :attached_photo

Please advise.

If I add a text field for the title. Then params are like the following: "photo"=>{"title"=>""}, "commit"=>"submit", "painter_id"=>"1" It seems :attached_photo isn't being passed. — Brian
– Brian, Commented Oct 13, 2013 at 17:19
Does the file not get passed even when you upload it with the file field? I tested with a paperclip photo upload on one of my applications, and it only includes the parameter if a file is actually selected with the file field. — jvperrin
– jvperrin, Commented Oct 13, 2013 at 17:24
Which model to you have the has_attached_file :attached_photo code in? — jvperrin
– jvperrin, Commented Oct 13, 2013 at 17:43

jvperrin · Accepted Answer · 2013-10-13 17:51:15Z

2

If you want to make sure that a user uploads a photo when submitting this form, then you should add a validation on the Photo model like so:

validates_attachment_presence :attached_photo

Then if the user does not upload a photo, the form will re-render telling the user to upload a photo.

You will also want to use this strong parameters code to make sure you do not have an error if the photo param does not exist:

def photo_params
  params.require(:photo).permit(:title, :attached_photo) if params[:photo]
end

answered Oct 13, 2013 at 17:51

jvperrin

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