Rails: How to compare times and display error? - ruby-on-rails

Question

I'd like to check from and to times.
If from > to, I'd like display an error.
How can I edit my code?
Althogh I tried some codes with cover, include, I haven't be able to apply them to my code.
schema.rb
...
create_table "events", force: :cascade do |t|
t.time "from"
t.time "to"
...
schedules_controller.rb
...
def new
#schedule = Schedule.new
room = #schedule.rooms.build
schedule.events.build
end
def create
#schedule = current_user.schedules.build(schedule_params)
if #schedule.save
flash[:success] = "schedule created!"
redirect_to root_url
else
render 'new'
end
end
def edit
#day_max = Room.where("schedule_id = ?", #schedule.id).maximum(:day)
end
def update
#schedule.rooms.maximum(:day)
if #schedule.update(schedule_params)
flash[:success] = "schedule updated!"
redirect_to root_url
else
render 'edit'
end
end
_schedule_form.html.erb
<%= f.label :title %>
<%= f.text_field :title, class: 'form-control' %>
<br>
<%= f.label :departure_date %>
<div class="input-group date" id="datetimepicker">
<%= f.text_field :departure_date, :value => (f.object.departure_date.strftime('%b/%d/%Y') if f.object.departure_date), class: 'form-control' %>
<span class="input-group-addon">
<span class="glyphicon glyphicon-calendar"></span>
</span>
</div>
<script type="text/javascript">
$(function () {
$('#datetimepicker').datetimepicker({format:'MMM-DD-YYYY'});
});
</script>
<br>
<div id="room">
<%= f.simple_fields_for :rooms do |a| %>
<div id="room_<%= a.object.object_id %>">
<p class="day-number-element-selector"><b>Day <%= a.index.to_i + 1 %></b></p>
<%= a.simple_fields_for :events do |e| %>
<span class="form-inline">
<p>
<%= e.input :from, label: false %>
<%= e.input :to, label: false %>
</p>
</span>
<%= e.input :title, label: false %>
<% end %>
</div>
<%= a.link_to_add "Add event", :events, data: {target: "#room_#{a.object.object_id}"}, class: "btn btn-primary" %>
<%= a.input :room %>
<% end %>
</div>
It would be appreciated if you could give me how to check and display error.

Answer 1

You probably want to implement a validator in your event model, as explained in the documentation.
class Event < ActiveRecord::Base
validates :to, presence: true
validates :from, presence: true
validate do |e|
if e.from.present? && e.to.present? and e.from > e.to
e.errors[:base] << "To time must be after from time"
end
end
end