Re: Ruby 1.9.2 Date issues

On Tue, Jan 11, 2011 at 3:49 AM, Robert Klemme
<[e-mail]> wrote:
> On Tue, Jan 11, 2011 at 1:45 AM, keldog <[e-mail]> wrote:
>> Hello all...
>>
>> Wondering if someone can help me out with a date issue.
>>
>> My environment:
>> ruby: 1.9.2p0
>> rails: 3.0.3
>> mac os x
>>
>> My issue:
>>
>> From what I've been reading, the date format has been changed in
>> 1.9.2. =A0So, saving dates in the "mm/dd/yyy" format has been an issue
>> since 1.9.2 is saving as "dd/mm/yyyy"
>
> What exactly do you mean by "saving"? =A0Both "mm/dd/yyy" and
> "dd/mm/yyyy" are just textual representations of a Date. =A0If you want
> to be sure what conversion is used you can use Date#strftime:

I'm pretty sure he's talking about how Date.parse interprets a string
of the form "1/2/2011"

This form is ambiguous of course, in the US it's normal meaning would
be January 1, 2011, where in most of the civilized world it would be
February 1, 2011

Date.parse in ruby 1.8.6 tries to use heuristics to decide how to
resolve the ambiguity. Ruby 1.9 (and IIRC 1.8.7 as well) did away with
this and simply interprets such an input string as February 1.
>
> 09:44:35 ~$ irb19 -r date
> Ruby version 1.9.2
> irb(main):001:0> d =3D Date.today
> =3D> #<Date: 2011-01-11 (4911145/2,0,2299161)>
> irb(main):002:0> d.to_s
> =3D> "2011-01-11"
> irb(main):003:0> d.strftime '%m/%d/%Y'
> =3D> "01/11/2011"
> irb(main):004:0> d.strftime '%d/%m/%Y'
> =3D> "11/01/2011"
> irb(main):005:0>
>
> If you save via Marshal there should be no issues. =A0Note also that
> there are some built in formats:
>
> irb(main):012:0> d.rfc3339
> =3D> "2011-01-11"
> irb(main):013:0> d.rfc2822
> =3D> "Tue, 11 Jan 2011 00:00:00 +0000"
> irb(main):014:0> d.rfc822
> =3D> "Tue, 11 Jan 2011 00:00:00 +0000"

True but probably mostly irrelevant if I'm interpreting the OPs
questions correctly.

>> I have a jQuery plugin that uses the date picker and displays in the
>> format of "mm/dd/yyyy" =A0However, sometimes the date saves and other
>> times it doesn't because of ruby expecting the changed format (mm/dd/
>> yyyy). =A0For example:
>>
>> 3/1/2011 saves as 1/3/2011
>> 3/13/2011 doesn't save (returns "")
>
> I would expect the date picker to return a Date and not a String.
> What am I missing?

The date picker is javascript in a browser, the 'date' needs to be
transported via a parameter in a HTTP post, which only allows strings.
 So the date needs to arrive at the server in the form of a string,
which then gets parsed into a ruby date, and this is ultimately done
by Date._parse which is the method whose semantics have changed in
Ruby 1.8.7/1.9
>
>> I have the following code in my model to inspect the date (in my case,
>> start_date of a course):
>>
>> [code]
>> =A0before_filter :fix_dates

before_filter is a controller method, not a model method isn't it?
Sorry pure-ruby folks but the OPs question is in the context or Rails.

To fix this I think the OP wants to do the conversion from the string
in the controller, so that it's already a ruby Date or DateTime by the
time AR sees it.  Exactly how to do this depends on the controller
itself.  Asuming that the model involved is Foo, and we have a
standard FoosController and a standard form being posted, something
like this:

def create
  if (params[:foo] && date_string =3D params[:foo][:start_date])
    params[:start_date] =3D Date.strptime(date_string), "%m/%d/%Y")
  end

  @foo =3D Foo.create(params[:foo])
  if @foo.save
      #handle case when foo is valid
  else
     #handle validation errors
  end
end

HTH

--=20
Rick DeNatale

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