How to display date variables on site using Ruby on Rails? - ruby-on-rails

Question

I wanted to display my time variables to see when pass has started and when will it end but don't know how and couldn't find solution.
I tried something very simple but it doesn't work:
show.html.erb
<h1><%= #pass.name %></h1>
<p><%= #pass.valid_from %></p>
<p><%= #pass.valid_until %></p>
create_passes.rb migration
class CreatePasses < ActiveRecord::Migration[7.0]
def change
create_table :passes do |t|
t.time :valid_from
t.time :valid_until
t.boolean :is_time_limited
t.integer :entries_left
t.string :name
t.timestamps
end
end
end
passes_controller.rb
class PassesController < ApplicationController
def index
#passes = Pass.all
end
def show
#pass = Pass.find(params[:id])
end
def new
#pass = Pass.new
end
def create
#pass = Pass.new(pass_params)
if #pass.save
redirect_to #pass
else
render :new, status: :unprocessable_entity
end
end
def edit
#pass = Pass.find(params[:id])
end
def update
#pass = Pass.find(params[:id])
if #pass.update(pass_params)
redirect_to #pass
else
render :edit, status: :unprocessable_entity
end
end
def destroy
#pass = Pass.find(params[:id])
#pass.destroy
redirect_to root_path, status: :see_other
end
private
def pass_params
params.require(:pass).permit(:name, :is_time_limited, :valid_from, :valid_until, :entries_left)
end
end
new/edit pass form view
<%= form_with model: #pass do |form| %>
<div>
<%= form.label :name %><br>
<%= form.text_field :name %>
<% #pass.errors.full_messages_for(:name).each do |message| %>
<div><%= message %></div>
<% end %>
</div>
<div>
<%= form.label :valid_from %><br>
<%= form.date_field :valid_from %>
<% #pass.errors.full_messages_for(:name).each do |message| %>
<div><%= message %></div>
<% end %>
</div>
<div>
<%= form.label :valid_until %><br>
<%= form.date_field :valid_until %>
<% #pass.errors.full_messages_for(:name).each do |message| %>
<div><%= message %></div>
<% end %>
</div>
<div>
<%= form.submit %>
</div>
<% end %>
rails server log
Started GET "/passes/2" for ::1 at 2022-08-10 18:18:18 +0200
Processing by PassesController#show as HTML
Parameters: {"id"=>"2"}
(0.1ms) SELECT sqlite_version(*)
↳ app/controllers/passes_controller.rb:7:in `show'
Pass Load (0.2ms) SELECT "passes".* FROM "passes" WHERE "passes"."id" = ? LIMIT ? [["id", 2], ["LIMIT", 1]]
↳ app/controllers/passes_controller.rb:7:in `show'
Rendering layout layouts/application.html.erb
Rendering passes/show.html.erb within layouts/application
Rendered layouts/_navbar.html.erb (Duration: 1.0ms | Allocations: 724)
Rendered passes/show.html.erb within layouts/application (Duration: 2.8ms | Allocations: 1670)
Rendered layout layouts/application.html.erb (Duration: 6.9ms | Allocations: 4039)
Completed 200 OK in 31ms (Views: 7.5ms | ActiveRecord: 0.5ms | Allocations: 5333)
Also, is it better to use time or datatime type for dates and time?

Answer 1

Ok I believe I know why you are not getting any values.
You setup your DB to use a time field
t.time :valid_from
t.time :valid_until
But you are using a date_field in the view:
form.date_field :valid_from
You need to change this to:
form.time_field :valid_from
The difference between time or datetime is datetime includes a DATE and a TIME, where TIME ONLY has a time so it depends on what your use case is. You can also use just a date and then it would be
form.date_field :valid_from
If you need dates you will need to change your model and DB to use either t.date or t.datetime. If you don't have a lot of information in your DB you can do a rails db:rollback and modify your migration file would be the quickest and easiest way to fix it. IF you DO have data you will have to create a new migration to change the fields.