Paperclip + ImageMagick help needed

[Rafa_F]

Hey there, I want to be able to upload multiple images at once on my
website. I can only upload one image at a time at the moment. Can
anybody lead me in the right direction? Here’s my code

/app/models/listing.rb

class Listing < ActiveRecord::Base
has_attached_file :image, :styles => { :medium => “200x”, :thumb =>
“100x100>” }, :default_url => “default.jpg”
validates_attachment_content_type :image, :content_type =>
/\Aimage/.*\Z/
end

/app/controllers/listings_controller.rb

…
private

Use callbacks to share common setup or constraints between actions.

def set_listing
@listing = Listing.find(params[:id])
end

Never trust parameters from the scary internet, only allow the white

list through.
def listing_params
params.require(:listing).permit(:name, :description, :price, :image)
end
end

/app/views/listings/_form.html.erb

<%= form_for @listing, :html => { :multipart => true } do |f| %>
…
…

<%= f.file_field :image, class: "form-control" %>

<%= f.submit class: "btn btn-primary" %>

<% end %>

/app/views/listings/show.html.erb

<%= notice %>

<%= image_tag @listing.image.url(:medium) %>
…

/app/views/listings/index.html.erb

Listing listings

... <% @listings.each do |listing| %> ...

Image	Name
<%= image_tag listing.image.url(:medium) %>	<%= listing.name %>

[anmueller]

list through.

Listing listings

<%= image_tag listing.image.url(:medium) %> <%= listing.name %> ...

In order to do this (no matter which file attachment system you choose)
you will need to refactor your application slightly. You need a model
instance per image uploaded, so the usual way to do this is with a
nested form. You create a form on a parent object that has_many of the
image objects. If the Listing model is the parent, then you can add an
Image model to belong to that listing, in a one-to-many relationship.
Then you set up the following (this is pseudocode, off the top of my
head, not guaranteed to work as written, but the right idea, IMO):

class Listing < ActiveRecord::Base
has_many :images
accepts_nested_attributes_for :images, allow_destroy: true, reject_if:
:all_blank
end

class Image < ActiveRecord::Base
belongs_to :listing
has_attached_file :image
end

class ListingsController < ApplicationController
… all the usual CRUD actions here
private
def listing_params
params.require(:listing).permit(:name, :description, :price,
images_attributes: [:id, :image, :_destroy])
end
end

And finally, in your form_for @listing, you need to create a very
particularly named field in order to get this all to work together:

<%= file_field_tag(‘listing_images_attributes_image’, multiple: true,
:name => “listing[images_attributes][][image]”) %>

That last part is ripped out of working code using Paperclip.

Things to note here:

1. It’s using the file_field_tag generator (long-hand) rather than the
   f.file_field that you may be used to. This is so that the name can be
   exactly what it needs to be to “trick” the accepts_nested_attributes_for
   helper into accepting the attached files.
2. The multiple: true thing means that you will need a modern browser to
   use this (HTML5 feature).
3. The empty square-brackets in the middle of the name are the “secret
   sauce” that cause the individual files in the multiple file form element
   to be sent as separate files, rather than the last one “winning” or the
   data being concatenated and sent as form post body instead.
4. This type of field is only useful on an initial create or upload
   screen, not if you want to edit each of the attached files individually.
   I would put this particular form on the #new screen.

Once you have this working, you will need to make your #edit screen a
more traditional nested form. Read this for an example and further
ideas:
http://railscasts.com/episodes/196-nested-model-form-revised?view=asciicast

Walter

[anmueller]

Hey Walter. Thanks for all of the help!

I went through all of your steps. What should I write on my view page?

<%= image_tag @listing.image.url %>

<%= @listing.name %>

<%= number_to_currency(@listing.price) %>

<%= @listing.description %>

<%= link_to "Buy It Now", new_listing_order_path(@listing), class: "btn btn-primary", data: { no_turbolink: true } %>

<% if current_user == @listing.user %>
<%= link_to ‘Edit’, edit_listing_path(@listing), class: “btn btn-link”
%> |
<% end %>
<%= link_to ‘Back’, listings_path, class: “btn btn-link” %>

[anmueller]

On Feb 10, 2016, at 10:34 PM, Alexis M. [email protected] wrote:

Hey Walter. Thanks for all of the help!

I went through all of your steps. What should I write on my view page?

If you want to show all the images for a listing, the simplest thing is:

<%- @listing.images.each do |image| %>
<%= image_tag image.image_url %>
<%- end %>

Now there are lots of other refinements you could add to this – sizing
the images, extra HTML around each one, setting their order, etc. – but
this will get you started.

Walter

[anmueller]

On 11 February 2016 at 03:08, Walter Lee D. [email protected]
wrote:

has_attached_file :image
And finally, in your form_for @listing, you need to create a very particularly
named field in order to get this all to work together:

Once you have this working, you will need to make your #edit screen a more
traditional nested form. Read this for an example and further ideas:
http://railscasts.com/episodes/196-nested-model-form-revised?view=asciicast

What a great post, thanks Walter. That is going straight into
useful-notes-to-keep-in-case-I-ever-want-to-do-it.

Colin