Ufdjrw

I'm looking for the easiest and the most clever way to create interest_id(match) in one-click.

Here is my MVC :

user.rb

class User < ApplicationRecord
 has_many :interests, through: :opportunities
end

interest.rb

class Interest < ApplicationRecord
 belongs_to :opportunity
 belongs_to :user
end

opportunity.rb

class Opportunity < ApplicationRecord
 has_many :interests
end

InterestsController.rb

def create
 @user = current_user
 @opportunities = Opportunity.all
 @interest = Interest.new(interest_params)
 if @interest.save!
 redirect_to user_interests_path, notice: 'it works'
 else
 render :new, notice:"it doesn't work"
 end
end

def interest_params
 params.permit(
 :user_id,
 :opportunity_id)
end

user/show

<%= link_to "Match", user_interests_path(@user), class:"btn btn-primary", :method => :post %>

For now, I can't pass opportunities (nil). Could you please advise me about the easiest way to create interests? (New on RoR for 6 months).
Many thanks for your help.

If I understand correctly your relation schema, the Interest is the join record associating a User to (eventually) many Opportunity, and vice-versa (many-to-many relationship).

With that being said (and please correct me if I am wrong), you can do the following to achieve what you want:

# in user/show
<% @opportunities.each do |opportunity| %>
 <%= 
 link_to "Match opportunity #opportunity.id",
 user_interests_path(@user, opportunity_id: opportunity.id),
 class: "btn btn-primary",
 method: :post
 %>
<% end %>

# in interests_controller
def create
 if current_user.interests.create(opportunity_id: opportunity_id_param)
 redirect_to user_interests_path, notice: 'it works'
 else
 render :new, notice: "it doesn't work"
 end
end

private

def opportunity_id_param
 params.require(:opportunity_id)
end

This suggested code:

• requires the opportunity_id param for the interests#create action


• use current_user to automatically set the user_id on the Interest model, so the end-users can't send a user_id that are not theirs (if they could, then each user could create interest for other users without their agreement... security flaw)

On a side note, I strongly advise you to not select all existing Opportunity record and display it on your page: it does not scale. Someday, you will end up with hundreds of Opportunity records, making this list too big from a User Experience perspective.

I suggest a smarter approach, for example some kind of ordering + limit: max of 10 records ordered by "most interest", which can be accomplished by the following:

# in controller
@popular_opportunities = Opportunity
 .joins('LEFT JOINS interests ON interests.opportunity_id = opportunities.id')
 .order('count(interests.*) DESC, opportunities.id')
 .limit(10)

And then in the view, simply use @populator_opportunities instead of @opportunities.

Other options, like pagination, are also efficient in this case but IMO relevant ordering is the minimum.

First, you need to pass the ids of the opportunities you want to create interest some way, the best is a form, with checkboxes like MrShemek said, or a multi select dropdown.

I think you probably made some mistakes in User and Opportunity with the has_many and belong_to part:

class User < ApplicationRecord
 has_many :interests
 has_many :opportunities, through: :interests
 # interest is the one that links user and opportunity, it has the references for both user and opportunities
end
class Opportunity < ApplicationRecord
 has_many :interests
 has_many :users, through: :interests
 end

then in controller you could do

def create
 @user = current_user
 @opportunities = Opportunity.all
 @user.opportunity_ids = interest_params[:opportunity_ids] # it will create the interrests automatically for the given ids (because the relations of has_many through)
 if @user.save!
 redirect_to user_interests_path, notice: 'it works'
 else
 render :new, notice:"it doesn't work"
 end
end