如何在 Rails 中为 datetime_field_tag 设置默认值

Question

I am trying to have a default value for datetime_field_tag in my view:

=form_tag form_path, method: :get do
  =label_tag :sign_up_at, 'Sign up before:'
  =date_field_tag :sign_up_at, (params[:sign_up_at] || 
                               Time.zone.today.strftime("%Y-%m-%d"))

  =label_tag :last_seen_at, 'Last seen after:'
  =datetime_field_tag :last_seen_at, (params[:last_seen_at] || 
                                     Time.zone.now.strftime("%d-%m-%YT%H:%M"))

  =submit_tag 'Filter', class: 'btn-info'

This results in having a value tag in HTML:

<input type="datetime-local" name="last_seen_at" id="last_seen_at" value="22-05-2017T16:34">

My guess is, I am having some kind of a problem with parsing Time . Can anyone help, please? Thanks!

Updated according to @deephak's answer.

Answer 1

Just to supplement the other answer here: the datetime_field_tag helper is sensitive to the format of the datetime given to it. If, for example, the day, month, and year are in the wrong order, the value won't be displayed in the form input (and if you've got the developer console open, a warning message will be displayed).

It may depend on your locale, but the OP's "%d-%m-%YT%H:%M" format string has the year and day in reverse. "%Y-%m-%dT%H:%M" seemed to fix it in my trials.

Answer 2

You are using today which will give you just the date not time.

So, when you try to fetch time out of date rails will return 00:00

Example:

Time.zone.today
#=> Mon, 22 May 2017

Time.zone.now
#=> Mon, 22 May 2017 09:34:57 EDT -04:00

To fix this, change

Time.zone.today.strftime("%d-%m-%YT%H:%M")
#=> "22-05-2017T00:00"

to

Time.zone.now.strftime("%d-%m-%YT%H:%M")
#=> "22-05-2017T09:33"

# OR

Time.current.strftime("%d-%m-%YT%H:%M")
#=> "22-05-2017T09:33"

Answer 3

The answers above are correct, but if you would like to refactor this, you can setup a timeformat initializer.

config/time_formats.rb

Time::DATE_FORMATS[:datetime_field] = '%Y-%m-%dT%H:%M'

Then when setting the value you can use:

Time.zone.today.to_s(:datetime_field)

Remember to restart your rails s after changing the initializer.

Answer 4

You can try

date_field_tag(:start_date, value = nil, options = {})

or if you want to submit onchange

date_select(:start_date, value = nil, options = {},onchange: "this.form.submit();")

Answer 5

If you want to try more closer, do like below.

<%= datetime_field_tag 'start_at_update', Time.zone.now.strftime("%Y-%m-%dT00:00:00"), placeholder: '환율 기간(시작)', class: 'form-control w-50 d-inline-block h-auto w-auto ml-2 value-start-at_update', step: '1' %>