User_id is not fetched in join table - ruby-on-rails

Question

I have a the following form:
<h2>Add collaborators to the wiki <strong><%= #wiki.title %></strong></h2>
<%= form_for ([#wiki, #collaboration]) do |f| %>
<% #users.each do |user| %>
<p><%= check_box_tag 'user_ids[]', user.id %>
<%= label_tag 'user_ids[]', user.email %>
<% end %>
<p> <%= f.submit %> <p>
<% end %>
It should do the following, provide the possible the check users => an then all this users should be able to edit this particular form (#wiki)
I therefor created a join table which takes a user_id and wiki_id. If i try to
to save the collaborators in through the form it does not seem to work however.
I get this in my rails c
#<Collaboration id: 1, user_id: nil, wiki_id: 1, created_at: "2015-02-20 10:40:49", updated_at: "2015-02-20 10:40:49">,
So it does not seem to fetch the user.
My controller is set up like this
class CollaborationsController < ApplicationController
def new
#wiki = Wiki.find(params[:wiki_id])
#collaboration = #wiki.collaborations.new
#users = User.all
end
def create
#wiki = Wiki.find(params[:wiki_id])
#selected users
#collaboration = #wiki.collaborations.build(user_id: params[:user_id])
if #collaboration.save
redirect_to wikis_path, notice: "Wiki shared."
else
flash[:error] = "Error creating wiki. Try again."
render :new
end
end
end
And my schema file looks like this:
create_table "collaborations", force: :cascade do |t|
t.integer "user_id"
t.integer "wiki_id"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "users", force: :cascade do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", default: 0, null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at"
t.datetime "updated_at"
t.string "role"
end
add_index "users", ["email"], name: "index_users_on_email", unique: true
add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
create_table "wikis", force: :cascade do |t|
t.string "title"
t.text "body"
t.boolean "private"
t.integer "user_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "wikis", ["user_id"], name: "index_wikis_on_user_id"
create_table "wikis_and_collaborators", force: :cascade do |t|
t.integer "user_id"
t.integer "wiki_id"
t.datetime "created_at"
t.datetime "updated_at"
end
end
Any thoughts on what goes wrong here?

Answer 1

Let's say we have params[:user_ids] = [123, 456, 789]
You can say #wiki.user_ids = [123, 456, 789]; #wiki.save and that will make the join records automatically. So, this is actually an update on the wiki object, and your form should be editing the Wiki object too. I would do it like so:
<h2>Add collaborators to the wiki <strong><%= #wiki.title %></strong></h2>
<%= form_for (#wiki) do |f| %>
<% #users.each do |user| %>
<p><%= check_box_tag 'wiki[user_ids][]', user.id, #wiki.user_ids.include?(user.id) %>
<%= label_tag 'wiki[user_ids][]', user.email %>
<% end %>
<p> <%= f.submit %> <p>
<% end %>
This will submit to the WikiController#update action, or the WikiController#create action, depending on whether #wiki is a new record or not.
params will be params = {:id => 6, :wiki => {:user_ids => [123, 456, 789]}}, where 6 is an example wiki id.
Following convention, you wouldn't be accessing the CollaborationsController at all, you'd be accessing the WikisController, since it's a Wiki that's being updated. The WikisController#update action would be totally standard:
def update
#wiki = Wiki.find_by_id(params[:id])
#wiki.update_attributes(params[:wiki])
redirect_to wiki_path(#wiki) #or whatever
end