Preventing multiple POSTS in Ruby on Rails app - Rails 4 - ruby-on-rails

Question

I am unsure what is happening.
I have an attending button that user can click to attend an event.
when a user clicks on the attend button i get multiple post request in my terminal
this then displays the user attending the event 3 times
This only happens in the firefox browser
can one kindly tell me how to prevent this?
multiple post displayed in terminal:
Started POST "/attending_socials?social_id=new-members-night-out-west-london" for 127.0.0.1 at 2017-01-27 13:56:26 +0000
Processing by AttendingSocialsController#create as HTML
Parameters: {"authenticity_token"=>"G/9QyoKBaTTsivCKmcKAFO7RoPC6B7Lm6C4G7er2pGYIjYirJwcCUDXCrCoODk5tPl3cRMQUZM6fouQrLnvjRg==", "social_id"=>"new-members-night-out-west-london"}
Social Load (0.1ms) SELECT "socials".* FROM "socials" WHERE "socials"."slug" = ? ORDER BY "socials"."id" ASC LIMIT 1 [["slug", "new-members-night-out-west-london"]]
User Load (0.1ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT 1 [["id", 20]]
(0.1ms) begin transaction
SQL (0.5ms) INSERT INTO "attendances" ("attendable_id", "attendable_type", "user_id", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?) [["attendable_id", 11], ["attendable_type", "Social"], ["user_id", 20], ["created_at", "2017-01-27 13:56:26.450155"], ["updated_at", "2017-01-27 13:56:26.450155"]]
SQL (0.3ms) INSERT INTO "activities" ("parameters", "key", "owner_id", "owner_type", "trackable_id", "trackable_type", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?, ?, ?, ?) [["parameters", nil], ["key", "attendance.create"], ["owner_id", 20], ["owner_type", "User"], ["trackable_id", 156], ["trackable_type", "Attendance"], ["created_at", "2017-01-27 13:56:26.457301"], ["updated_at", "2017-01-27 13:56:26.457301"]]
(2.9ms) commit transaction
Redirected to http://localhost:3000/socials/new-members-night-out-west-london
Completed 302 Found in 19ms (ActiveRecord: 4.1ms)
Started POST "/attending_socials?social_id=new-members-night-out-west-london" for 127.0.0.1 at 2017-01-27 13:56:26 +0000
Processing by AttendingSocialsController#create as HTML
Parameters: {"authenticity_token"=>"G/9QyoKBaTTsivCKmcKAFO7RoPC6B7Lm6C4G7er2pGYIjYirJwcCUDXCrCoODk5tPl3cRMQUZM6fouQrLnvjRg==", "social_id"=>"new-members-night-out-west-london"}
Social Load (0.2ms) SELECT "socials".* FROM "socials" WHERE "socials"."slug" = ? ORDER BY "socials"."id" ASC LIMIT 1 [["slug", "new-members-night-out-west-london"]]
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT 1 [["id", 20]]
(0.1ms) begin transaction
SQL (0.4ms) INSERT INTO "attendances" ("attendable_id", "attendable_type", "user_id", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?) [["attendable_id", 11], ["attendable_type", "Social"], ["user_id", 20], ["created_at", "2017-01-27 13:56:26.488498"], ["updated_at", "2017-01-27 13:56:26.488498"]]
SQL (0.3ms) INSERT INTO "activities" ("parameters", "key", "owner_id", "owner_type", "trackable_id", "trackable_type", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?, ?, ?, ?) [["parameters", nil], ["key", "attendance.create"], ["owner_id", 20], ["owner_type", "User"], ["trackable_id", 157], ["trackable_type", "Attendance"], ["created_at", "2017-01-27 13:56:26.497129"], ["updated_at", "2017-01-27 13:56:26.497129"]]
(1.0ms) commit transaction
Redirected to http://localhost:3000/socials/new-members-night-out-west-london
Completed 302 Found in 19ms (ActiveRecord: 2.1ms)
Started POST "/attending_socials?social_id=new-members-night-out-west-london" for 127.0.0.1 at 2017-01-27 13:56:27 +0000
Processing by AttendingSocialsController#create as HTML
Parameters: {"authenticity_token"=>"G/9QyoKBaTTsivCKmcKAFO7RoPC6B7Lm6C4G7er2pGYIjYirJwcCUDXCrCoODk5tPl3cRMQUZM6fouQrLnvjRg==", "social_id"=>"new-members-night-out-west-london"}
Social Load (0.2ms) SELECT "socials".* FROM "socials" WHERE "socials"."slug" = ? ORDER BY "socials"."id" ASC LIMIT 1 [["slug", "new-members-night-out-west-london"]]
User Load (0.1ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT 1 [["id", 20]]
(0.1ms) begin transaction
SQL (0.3ms) INSERT INTO "attendances" ("attendable_id", "attendable_type", "user_id", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?) [["attendable_id", 11], ["attendable_type", "Social"], ["user_id", 20], ["created_at", "2017-01-27 13:56:27.510657"], ["updated_at", "2017-01-27 13:56:27.510657"]]
SQL (0.1ms) INSERT INTO "activities" ("parameters", "key", "owner_id", "owner_type", "trackable_id", "trackable_type", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?, ?, ?, ?) [["parameters", nil], ["key", "attendance.create"], ["owner_id", 20], ["owner_type", "User"], ["trackable_id", 158], ["trackable_type", "Attendance"], ["created_at", "2017-01-27 13:56:27.516075"], ["updated_at", "2017-01-27 13:56:27.516075"]]
(2.7ms) commit transaction
Redirected to http://localhost:3000/socials/new-members-night-out-west-london
Completed 302 Found in 16ms (ActiveRecord: 3.5ms)
route.rb:
resources :attending_socials, only: [:create, :destroy]
schema:
ActiveRecord::Schema.define(version: 20170121184409) do
create_table "attendances", force: :cascade do |t|
t.integer "attendable_id"
t.string "attendable_type"
t.integer "user_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "attendances", ["attendable_type", "attendable_id"], name: "index_attendances_on_attendable_type_and_attendable_id"
add_index "attendances", ["user_id"], name: "index_attendances_on_user_id"
end
attendance.rb
class Attendance < ActiveRecord::Base
belongs_to :user
belongs_to :attendable, polymorphic: true
end
attending_socials_controller.rb
class AttendingSocialsController < ApplicationController
before_action :set_social
def create
if Attendance.create(attendable: #social, user: current_user)
redirect_to :back, notice: 'Attending Social'
else
redirect_to :back, alert: 'Something went wrong...*sad panda*'
end
end
def destroy
Attendance.where(attendable_id: #social.id, user_id: current_user.id).first.destroy
redirect_to :back, notice: 'Not Attending Social'
end
private
def set_social
#social = Social.friendly.find(params[:social_id] || params[:id])
end
end
views file:
<div><%= link_to 'Attend testing', attending_socials_path(social_id: #social), method: :post %></div>

Answer 1

You could use this:
Attendance.find_or_create_by(attendable: #social, user: current_user)
given a user can attend each event only once