Parsing daterange param as two attributes - Rails 4, Datetimepicker GEM - ruby-on-rails

Question

I have a model Foo with two datetime attributes called start_time and end_time. Foo has a validation logic for each attribute:
Model:
...
validate :dates_logic_validation, on: :save
...
def dates_logic_validation
if start_time < Time.now
errors.add(:start_time, 'Start time must be greater or equal to today\'\s date')
return false
elsif start_time > end_time
errors.add(:end_time, 'End time must be greater than start time')
return false
else
true
end
end
The validation error handling works fine when I try to create / update Foo via the console. Using datetimepicker gem, I am getting both dates in params hash. In my foos#create, I want to be able to parse this daterange param and assign it foo.start_time and foo.end_time. To do so, I added an instance method:
def parse_date_range(daterange) #<= param is passed as "12/02/2015 - 01/14/2016"
start_time = daterange.split("-")[0].strip!
end_time = daterange.split("-")[1].strip!
update_attributes(start_time: start_time, end_time: end_time)
end
then calling it like so:
Controller (#create):
def create
#foo= Foo.new(foo_params)
#foo.parse_date_range(params[:daterange])
if #foo.valid?
#foo.save
redirect_to foos_path(#foo)
else
render :new
end
end
and here is where the music stops. If I log #{start_time} and #{end_time} after I call parse_data_range on #foo, both will be empty. Which suggests that I probably can't call update_attributes on a non-existing object. If that's the case, what would be the best solution?

Answer 1

I think it's a mistake to do a second database query (update_attributes) when instead you can extract the dates from params in the controller like this:
class FoosController < ApplicationController
before_action :extract_start_end_times, only: :create
def create
#foo = Foo.new(foo_params)
if #foo.valid?
#foo.save
redirect_to foos_path(#foo)
else
render :new
end
end
# ...
private
def extract_start_end_times
return unless params[:daterange].present?
daterange = params.delete(:daterange)
start_time, end_time = daterange.split(/\s*-\s*/)
.map {|date| Date.strptime(date, '%m/%d/%Y') }
params.merge!(start_time: start_time, end_time: end_time)
end
end
Note the use of Date.strptime(date, '%m/%d/%Y'). This is necessary because your dates are in an ambiguous format (Ruby has no way to know if "12/02/2015" is Dec. 2 or Feb. 12).
If you're using strong parameters you may have to modify your foo_params method to accommodate the start_time and end_time params.

Answer 2

This should get to work.
update_attributes(start_time: Date.parse(start_time), end_time: Date.parse(end_time))
You can also use
DateTime.parse("12/02/2015")
=> Thu, 12 Feb 2015 00:00:00 +0000