adding a new column **attachment** in existing table in ruby on rails - ruby-on-rails

Question

Ok So I have a simple rails application called ticket. here I create ticket and store into database. I generated it using scaffold.
It has 5 columns. ( I generated it using scaffold)
Name
Seat id seq
Address
Price paid
Email Address
And the application is working fine. I can create , edit, and update the ticket. I am much interested in creating the ticket rather than editing and deleting.
Now I want to add a new column in the database named attachment where a person can upload word, pdf files. I have seen many tutorials but none is explaining how I can incorporate into an existing table which already have some fields.
tickets_controller.rb
class TicketsController < ApplicationController
before_action :set_ticket, only: [:show, :edit, :update, :destroy]
def index
#tickets = Ticket.all
end
def show
end
def new
#ticket = Ticket.new
end
def edit
end
def create
#ticket = Ticket.new(ticket_params)
respond_to do |format|
if #ticket.save
format.html { redirect_to #ticket, notice: 'Ticket was successfully created.' }
format.json { render :show, status: :created, location: #ticket }
else
format.html { render :new }
format.json { render json: #ticket.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if #ticket.update(ticket_params)
format.html { redirect_to #ticket, notice: 'Ticket was successfully updated.' }
format.json { render :show, status: :ok, location: #ticket }
else
format.html { render :edit }
format.json { render json: #ticket.errors, status: :unprocessable_entity }
end
end
end
def destroy
#ticket.destroy
respond_to do |format|
format.html { redirect_to tickets_url, notice: 'Ticket was successfully destroyed.' }
format.json { head :no_content }
end
end
private
def set_ticket
#ticket = Ticket.find(params[:id])
end
def ticket_params
params.require(:ticket).permit(:name, :seat_id_seq, :address, :price_paid, :email_address)
end
end
tickets Model
class Ticket < ApplicationRecord
end
_form.html.erb
<%= form_for(ticket) do |f| %>
<% if ticket.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(ticket.errors.count, "error") %> prohibited this ticket from being saved:</h2>
<ul>
<% ticket.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %>
<%= f.text_field :name %>
</div>
<div class="field">
<%= f.label :seat_id_seq %>
<%= f.text_field :seat_id_seq %>
</div>
<div class="field">
<%= f.label :address %>
<%= f.text_area :address %>
</div>
<div class="field">
<%= f.label :price_paid %>
<%= f.text_field :price_paid %>
</div>
<div class="field">
<%= f.label :email_address %>
<%= f.text_field :email_address %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
new.html.erb
<h1>New Ticket</h1>
<%= render 'form', ticket: #ticket %>
<%= link_to 'Back', tickets_path %>
I found some on some of the sources that to upload a document we need to create a table with three columns ( filename, content_type, data) , and I thought to add these column into the existing tickets table, but then I don't know what chnages i need to make in the new.html.erb file. On this file i am loading the form where you can enter the information, and I want to show a field to upload a file on this page.
ruby -v : 2.2.6p396
rails -v : 5.0.0.1 ( Please reply in way that I can use the solution on the rails 4.0 too)

Answer 1

As #Brad mentioned you can use paperclip or carrierwave to add attachment. I will use paperclip in this example. ( Note: I'm using rails 5.0.0.1 in this example, and comand rails db:migrate. in Rails 4.x it will be rake db:migrate)
Let's do some scaffolding first and then you can alter your code to suits your needs.
rails g scaffold User name:string
rails g scaffold Post title:string body:text user:references
Add has_many :posts to User model, and run rails db:migrate
Add gem file: gem "paperclip", "~> 5.0.0" and run: bundle install
Let's generate paperclip attachment: rails generate paperclip user docs and run rails db:migrate
Add attachment, validation and content type to our User model:
has_attached_file :docs
validates_attachment :docs, :content_type => {:content_type => %w(application/pdf application/msword application/vnd.openxmlformats-officedocument.wordprocessingml.document)}
Add to users_controller.rb strong params for attribute whitelisting :
def user_params
params.require(:user).permit(:name, :docs)
end
The form’s encoding must be set to multipart/form-data for uploading files html: { multipart: true } so for our attachment we need to alter our form partial app/views/users/_form.html.erb:
<%= form_for #user, html: { multipart: true } do |f| %>
And add required fields to our form:
<div class="field">
<%= f.label :docs %>
<%= f.file_field :docs %>
</div>
After restarting our server rails s, and going to url users/new we can see new field attachment. After uploading a document we can check in our console if it's uploaded: rails c and run for example User.all, which shows that our fields in DB are populated:
And the last step would be to show the document in our views app/views/users/show.html.erb so that users can download or open it in the browser:
<%= link_to "My document", #user.docs.url, target: "_blank" %>
EDIT
Let's get back to your project and do it:
First you should add Paperclip gem to your Gemfile gem "paperclip", "~> 5.0.0" and to run bundle install in command line.
Generate attachment: rails generate paperclip ticket attachment ( This will generate the migration file and add attachment field to it )
run rails db:migrate ( rake db:migrate in Rails 4 )
go to Ticket model and add:
has_attached_file :attachment
validates_attachment :attachment, :content_type => {:content_type => %w(application/pdf application/msword application/vnd.openxmlformats-officedocument.wordprocessingml.document)}
Then to tickets_controller.rb and edit strong params:
def ticket_params
params.require(:ticket).permit(:name, :seat_id_seq, :address, :price_paid, :email_address, :attachment)
end
Go to your partial _form.html.erb:
Edit this code below in your form:
<%= form_for #ticket, html: { multipart: true } do |f| %>
Add this code below to your form: (That would be new field with attachment )
<div class="field">
<%= f.label :attachment %>
<%= f.file_field :attachment %>
</div>
and the last step to your show page add:
<%= link_to "My document", #ticket.attachment.url, target: "_blank" %>
restart your server, upload the document and try if it works.

Answer 2

For adding attachments you can use a gem like carrierwave or paperclip. I personally use paperclip but both are good.
To do it manually:
In your terminal cd to app folder and run:
rails g migration AddAttachmentToTickets attachment:blob
run rails 4 rake db:migrate or in rails 5 rails db:migrate
in your ticket form you can now add:
<div class="field">
<%= f.label :attachment %>
<%= f.file_field :attachment %>
</div>
and make sure you permit this in your ticketsController params. It should look something like this:
def ticket_params
params.require(:ticket).permit(:ticket_number,:description, :attachement)
end
Hope this helps.