In my application I want only current user to edit and delete his/her stuff and for others stuff he just able to show it. I’m using devise with rails 4. Here my files. Migration rails g migration AddUserIdToStudents user:references user.rb class User < ActiveRecord::Base has_many :students end student.rb
class Student < ActiveRecord::Base belongs_to :user end student_controller.rb
class StudentsController < ApplicationController
before_action :authenticate_user!
before_action :set_student, only: [:show, :edit, :update, :destroy]
def index
end
Branch wise students
def mechanical
@students = Student.where(Branch: “Mechanical Engineering”)
end
def infomation_technology
@students = Student.where(Branch: “Information Technology”)
end
def new
@student = current_user.students.build
end
def edit
end
def create
@student = current_user.students.build(student_params)
respond_to do |format|
if @student.save
format.html { redirect_to @student}
format.json { render :show, status: :created, location: @student }
else
format.html { render :new }
format.json { render json: @student.errors, status: :unprocessable_entity }
end
end
end
private
def set_student
@student = Student.find(params[:id])
end
def student_params
params.require(:student).permit( :University_Roll_Number, :avatar, :Department_Type, :user_id)
end
end
_actions.html.erb
<% @students.each do |student| %>
<% if current_user.try(:admin?) %> <%= link_to student, :class=> “btn waves-light waves-effect grey darken-4” do %> Show <% end %> <%= link_to edit_student_path(student), :class=> “btn waves-light waves-effect grey darken-4” do %> Edit <% end %> <%= link_to student, method: :delete, data: { confirm: ‘Are you sure?’ }, :class=> “btn waves-light waves-effect grey darken-4” do %> Delete <% end %>
<% elsif @student.user_id == current_user.id %> <%= link_to student, :class=> “btn waves-light waves-effect grey darken-4” do %> Show <% end %> <%= link_to edit_student_path(student), :class=> “btn waves-light waves-effect grey darken-4” do %> Edit <% end %> <%= link_to student, method: :delete, data: { confirm: ‘Are you sure?’ }, :class=> “btn waves-light waves-effect grey darken-4” do %> Delete <% end %>
<% else %> <%= link_to student, :class=> “btn waves-light waves-effect grey darken-4” do %> Show <% end %> <% end %>
With all that configuration I’m getting following error undefined method `user_id’ for nil:NilClass. In my students table user_id is passing but still facing this error. Where am I doing wrong.