Getting error when showing the purchases of the user,when showing the product he bought i get an error for product image and title - ruby

Question

This is the relationship i have between User,Gig(product),and Purchase table that records the purchase.
class User < ActiveRecord::Base
has_many :gigs
has_many :purchases, foreign_key: 'buyer_id'
has_many :sales, foreign_key: 'seller_id', class_name: 'Purchase'
end
class Gig < ActiveRecord::Base
has_many :purchases
has_many :buyers, through: :purchases
has_many :sellers, through: :purchases
end
class Purchase < ActiveRecord::Base
belongs_to :gig
belongs_to :buyer, class_name: 'User'
belongs_to :seller, class_name: 'User'
end
To record the purchase i use in my controller
def downloadpage
ActiveRecord::Base.transaction do
if current_user.points >= #gig.pointsneeded
#purchase = current_user.purchases.create(gig: #gig, seller: #gig.user)
if #purchase
current_user.points -= #gig.pointsneeded
#gig.user.points += #gig.pointsneeded
current_user.save
if #gig.user.save
render 'successful_download', locals:{link:#gig.boxlink}
end
end
else
redirect_to :back, notice: "You don't have enough points"
end
end
end
everything works when the buyer buys something from the seller,the points are transferred between accounts,and the buyer gets redirected to the final gig.
In my views i can do
<h1>You downloaded <%= current_user.purchases.count %> boxes</h1>
It will show the number of "gigs" the buyer made.
Now i want to show not just the number,but the title and the picture of the product he bought.This is what i tried
<div class="row experiment">
<% current_user.purchases.each do |gig| %>
<div class="well for-h1-gig-second col-xs-6 col-sm-4 col-lg-3 ">
<%= link_to (image_tag gig.image.url(:medium), :class=>"img-responsive"), gig %>
<h1><%= link_to gig.title, gig %></h1>
</div>
<% end %>
</div>
But it says,that it can not find the image and the title.
so i tried current_user.purchases.gig.each do |gig|
without success.
How do i fix it?
P.S: Please feel free to edit my title,for future readers,i couldn't formulate it better,thank you.

Answer 1

Your main problem is that current_user.purchases.each iterates through purchases - not gigs.
<div class="row experiment">
<% current_user.purchases.each do |purchase| %>
<% gig = purchase.gig %>
<div class="well for-h1-gig-second col-xs-6 col-sm-4 col-lg-3 ">
<%= link_to(image_tag gig.image.url(:medium), :class=>"img-responsive"), gig %>
<h1><%= link_to gig.title, gig %></h1>
</div>
<% end %>
</div>
Also to some of the other issues:
class User < ActiveRecord::Base
has_many :gigs # not going to work.
end
The reason it's not going to work is that the relation between user and gig goes through purchases and the buyer_id and seller_id foreign keys. Rails does not support relations that depend on multiple keys.
If you want to select gigs where the user is either seller or buyer you could use:
Gig.joins(:purchases).where('purchases.buyer_id=? OR purchases.seller_id=?', [current_user.id, current_user.id])

Answer 2

Try adding the association on user:
class User < ActiveRecord::Base
has_many :purchases, foreign_key: 'buyer_id'
has_many :gigs, through: :purchases, source: :buyer
has_many :sales, foreign_key: 'seller_id', class_name: 'Purchase'
end
Then you should be able to loop through current_user.gigs