Sinatra undefined method `user_id' for nil:NilClass - ruby

Question

I keep running into this error in my application_controller and I can't seem to figure out the issue.
Everything seems to work fine until I have to edit a gig. I know I'll need to refactor my code or else I will run into this issue again.
Any help is appreciated!
Error-
NoMethodError at /gigs/:id/edit
undefined method `user_id' for nil:NilClass
Application Controller
require './config/environment'
class ApplicationController < Sinatra::Base
configure do
set :public_folder, 'public'
set :views, 'app/views'
enable :sessions
set :session_secret, "secret"
end
get "/" do
erb :welcome
end
get "/signup" do
erb :'/users/signup'
end
post "/signup" do
if User.find_by(:email => params["email"])
puts "Sorry, there is already an account using this email address"
redirect "/login"
else
user = User.create(params)
if user.save
session[:user_id] = user.id
redirect "/"
else
puts "Sorry. All fields must be filled out."
redirect "/signup"
end
end
# #user = User.new(name: params["name"], email: params["email"], password: params["password"])
# #user.save
##user = User.new(params)
# #user.save
#session[:user_id] = #user.id
#puts params
#redirect '/users/home'
#session[:name] = params[:name]
end
get "/login" do
erb :'users/login'
end
post '/login' do
#user = User.find_by(:email => params["email"])
if #user && #user.authenticate(params["password"])
session[:user_id] = #user.id
redirect "/home"
end
redirect "/login"
end
get '/home' do
#user = User.find(session[:user_id])
erb :'users/home'
end
get '/gigs' do
if Helpers.is_logged_in?(session)
#user = Helpers.current_user(session)
#gigs = Gig.all
#if #user != nil
# #gigs = Gig.where(:user_id => #user.id)
erb :'gigs/index'
else
redirect "/login"
end
end
post '/gigs' do
#user = Helpers.current_user(session)
#gig = #user.gigs.create(params)
if #gig.save
puts "Gig has been saved."
else
puts "Please try again."
end
redirect "/gigs"
end
get '/gigs/new' do
if Helpers.is_logged_in?(session)
erb :'gigs/new'
else
redirect "/login"
end
end
get '/gigs/:id' do
if Helpers.is_logged_in?(session)
#user = Helpers.current_user(session)
#gig = Gig.find_by_id(params["id"])
if #gig.id == #gig.user_id
erb :'gigs/show'
else
redirect "/login"
end
else
redirect "/login"
end
end
get '/gigs/:id/edit' do
if Helpers.is_logged_in?(session)
#user = Helpers.current_user(session)
#gig = Gig.find_by_id(params[:id]) #["id"]
if #user.id == #gig.user_id
erb :'gigs/edit'
else
redirect "/login"
end
else
redirect "/login"
end
end
patch '/gigs/:id' do
#user = Helpers.current_user(session)
#gig = Gig.find_by_id(params["id"])
if #user.id == #gig.user_id
#gig.update(params["gig"])
redirect "/gigs/#{#gig.id}"
else
redirect "/login"
end
end
delete '/gigs/:id' do
#user = Helpers.current_user(session)
#gig = Gig.find_by_id(params["id"])
if #user.id == #gig.user_id
#gig.destroy
redirect "/gigs"
else
redirect "/login"
end
end
get '/logout' do
session.clear
redirect "/"
end
end
Helpers.rb
class Helpers
def self.is_logged_in?(session)
if session[:user_id] != nil
true
else
false
end
end
def self.current_user(session)
if self.is_logged_in?(session)
#user = User.find_by_id(session[:user_id])
end
end
end
Schema
ActiveRecord::Schema.define(version: 20200209173236) do
create_table "genres", force: :cascade do |t|
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "gigs", force: :cascade do |t|
t.string "bands"
t.string "location"
t.date "date"
t.string "time"
t.integer "user_id"
end
create_table "users", force: :cascade do |t|
t.string "name"
t.string "email"
t.string "password_digest"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
end
error log-
D, [2020-02-10T08:58:54.511675 #10068] DEBUG -- : ActiveRecord::SchemaMigration Load (0.1ms) SELECT "schema_migrations".* FROM "schema_migrations"
D, [2020-02-10T08:58:54.536858 #10068] DEBUG -- : User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1 [["id", 3]]
D, [2020-02-10T08:58:54.550769 #10068] DEBUG -- : Gig Load (0.1ms) SELECT "gigs".* FROM "gigs" WHERE "gigs"."id" = ? LIMIT 1 [["id", 0]]
2020-02-10 08:58:54 - NoMethodError - undefined method `user_id' for nil:NilClass:
/Users/melc/nyc-shows/app/controllers/application_controller.rb:115:in `block in <class:ApplicationController>'

Answer 1

According to the query
SELECT "gigs".* FROM "gigs" WHERE "gigs"."id" = ? LIMIT 1 [["id", 0]]
The ID you are trying to find is Zero so #gig is null (unless you really have a record with id 0)
#gig = Gig.find_by_id(params["id"])
if #user.id == #gig.user_id
You can protect against this like so
if #gig.nil? || #user.id == #gig.user_id
but my guess the issue is in the generation of the url rather than this method.
Also you can probably refactor the function more like this
get '/gigs/:id/edit' do
#user = Helpers.current_user(session)
#gig = Gig.find_by_id(params[:id])
redirect "/login" if #user.nil?
redirect "/invalid_gig_page" if #gig.nil? || #user.id != #gig.user_id
erb :'gigs/edit'
end