Detecting holidays


#1

Hi all,

Well, it took seven years, but I’ve finally been annoyed enough by
reports failing on national holidays to say something. Report writers
know the routine:

Them: Why did the report fail for Jan. 1st?
Me: National holiday. There was no data to grab. Ignore the failure.
Them: Oh, right.

Repeat again for Memorial Day, July 4th, Thanksgiving, and Christmas.

Is there a package out there that deals with national holidays (for any
nation)? The only thing I came across what date2, but that only seems
to handle Japanese national holidays. I guess I’m looking for
something like Perl’s Date::Calc [1] module or, more specifically, it’s
Date::calendar::Profiles [2] module. Or something like Perl’s
Date::Holidays::XXX [3] approach (I’m not sure which is preferred these
days).

Ideally, I’d like to be able to do something like:

if Date.today.is_national_holiday?
exit # Don’t run report on this day
end

And no, it’s not a simple matter of using something more flexible than
cron because some reports pull data from X days back or ahead, not on
the date they’re run.

Thoughts?

  • Dan

[1] http://search.cpan.org/~stbey/Date-Calc-5.4/Calendar.pod
[2]
http://search.cpan.org/~stbey/Date-Calc-5.4/lib/Date/Calendar/Profiles.pod
[3]
http://search.cpan.org/~jonasbn/Date-Holidays-0.08/lib/Date/Holidays.pm


#2

Try this:

class Date
def is_national_holiday?
this_year = self.year.to_s
# Not perfect; Thanksgiving and Easter change…
dates = [this_year + ‘-12-25’, this_year + ‘-12-24’, this_year +
‘-1-1’, this_year + ‘-7-4’, this_year + ‘-11-28’]

 if (dates.include?(self.to_s)):
    return true
 else
    return false
 end

end
end

irb(main):263:0> christmas = Date.parse(‘2007-12-25’)
=> #<Date: 4908919/2,0,2299161>
irb(main):264:0> christmas.is_national_holiday?
=> true
irb(main):265:0> today = Date.today
=> #<Date: 4908205/2,0,2299161>
irb(main):266:0> today.is_national_holiday?
=> false

Again, it doesn’t get Thanksgiving right or others that change like
Easter. If you want, I could hack it in; otherwise, this should get
you on the right path. :wink:

–Jeremy

On 1/2/07, Daniel B. removed_email_address@domain.invalid wrote:

Repeat again for Memorial Day, July 4th, Thanksgiving, and Christmas.

  • Dan

[1] http://search.cpan.org/~stbey/Date-Calc-5.4/Calendar.pod
[2]
http://search.cpan.org/~stbey/Date-Calc-5.4/lib/Date/Calendar/Profiles.pod
[3]
http://search.cpan.org/~jonasbn/Date-Holidays-0.08/lib/Date/Holidays.pm


My free Ruby e-book:
http://www.humblelittlerubybook.com/book/

My blogs:
http://www.mrneighborly.com/
http://www.rubyinpractice.com/


#3

On 1/2/07, Daniel B. removed_email_address@domain.invalid wrote:

Them: Why did the report fail for Jan. 1st?
Me: National holiday. There was no data to grab. Ignore the failure.
Them: Oh, right.
[snip]
Ideally, I’d like to be able to do something like:

if Date.today.is_national_holiday?
exit # Don’t run report on this day
end

Nice, but won’t this just change the problem to:

Them: Why is there no report for Jan. 1st?

What currently happens when the report ‘fails’? Could you generate an
empty report that says

‘No data available for today. Was it a holiday?’

That might solve your actual problem, without introducing a ‘holidays’
module. Though if your reports often fail for other reasons, perhaps
you do need to detect holidays to distinguish them rom real error
conditions.


#4

On 1/2/07, Daniel B. removed_email_address@domain.invalid wrote:

Hi all,

Well, it took seven years, but I’ve finally been annoyed enough by
reports failing on national holidays to say something. Report writers
know the routine:

<…>

The best way I know of checking for holidays is somehow keeping a
record of which dates are holidays in a given year. It can be a
database table, or some sort of configuration files when that isn’t
possible.

This record would have to be mantained manually, but it would be just
a simple case of editing the table/file every time you buy a new
calendar :).


#5

Kieran Tully wrote:

end

Nice, but won’t this just change the problem to:

Them: Why is there no report for Jan. 1st?

What currently happens when the report ‘fails’? Could you generate an
empty report that says

‘No data available for today. Was it a holiday?’

True, I may end up doing that in practice.

That might solve your actual problem, without introducing a ‘holidays’
module. Though if your reports often fail for other reasons, perhaps
you do need to detect holidays to distinguish them rom real error
conditions.

Yes, sometimes they fail for other reasons, such as the network or
database flaking out briefly. So, in practice I see myself doing
something like:

begin
# main report body
rescue ReportException
if Date.today.is_national_holiday?
# note in log that it was a holiday, in case anyone asks.
else
raise
end
end

It might be a little trickier than that in practice, but that’s the
general idea.

Regards,

Dan


#6

On 1/2/07, Daniel B. removed_email_address@domain.invalid wrote:

if Date.today.is_national_holiday?
exit # Don’t run report on this day
end

You may be able to build something that checks againt an iCalendar
file of holidays.


#7

On Jan 2, 2007, at 11:56 AM, Jeremy McAnally wrote:

   return true

irb(main):264:0> christmas.is_national_holiday?
=> true
irb(main):265:0> today = Date.today
=> #<Date: 4908205/2,0,2299161>
irb(main):266:0> today.is_national_holiday?
=> false

Again, it doesn’t get Thanksgiving right or others that change like
Easter. If you want, I could hack it in; otherwise, this should get
you on the right path. :wink:

For those sort of holidays you could use the Chronic gem to parse a
textual date:

irb(main):010:0> Chronic.parse(‘4th thursday in november’)
=> Thu Nov 22 11:00:00 -0500 2007

Still kind of a shame there isn’t just a ‘holidays’ gem.

-Mat


#8

I thought of Chronic (a fine library that I use often!); I’m toying
around with it right now and I think I have it figured out (without
using Chronic)…

I’ll re-post the code later on…and maybe make a little gem for those
(i.e, four people) who need it. :wink:

–Jeremy

On 1/2/07, Mat S. removed_email_address@domain.invalid wrote:

‘-1-1’, this_year + ‘-7-4’, this_year + ‘-11-28’]

Easter. If you want, I could hack it in; otherwise, this should get
-Mat


My free Ruby e-book:
http://www.humblelittlerubybook.com/book/

My blogs:
http://www.mrneighborly.com/
http://www.rubyinpractice.com/


#9

On 1/2/07, Mat S. removed_email_address@domain.invalid wrote:

For those sort of holidays you could use the Chronic gem to parse a
textual date:

irb(main):010:0> Chronic.parse(‘4th thursday in november’)
=> Thu Nov 22 11:00:00 -0500 2007

Still kind of a shame there isn’t just a ‘holidays’ gem.

Emacs has a really robust holidays library that’s not too lengthy,
perhaps a
good topic for a Ruby quiz or someone’s spare time to just port it to
Ruby?

/Nick


#10

Bira wrote:

record of which dates are holidays in a given year. It can be a
database table, or some sort of configuration files when that isn’t
possible.

This record would have to be mantained manually, but it would be just
a simple case of editing the table/file every time you buy a new
calendar :).

For fixed holidays, sure - I think that’s what Date::Calc does (i.e.
read an external file in, base on the selected country). But for
floating holidays I would prefer a general algorithm. Surely someone
can come up with a general algorithm for “3rd Thursday in November”,
etc. I’ll bet the Rails folks already have something, but I haven’t
looked.

Regards,

Dan


#11

Daniel B. wrote:

The best way I know of checking for holidays is somehow keeping a
floating holidays I would prefer a general algorithm. Surely someone
can come up with a general algorithm for “3rd Thursday in November”,
etc. I’ll bet the Rails folks already have something, but I haven’t
looked.

Regards,

Dan
And whatever solution, it needs to be dynamically updatable to account
for suddenly announced national “holidays”, like today happens to be -
doh!

Ken


#12

Well, the way I’m working it out is like AR’s dynamic finders. It
will have a few groups of dates hardcoded (like national holidays and
such), but then you can give it new groups in the form hashes of
arrays of dates with named “work_holidays” or “surprise_offdays” and
then call the method like is_a_work_holiday? or is_a_surprise_offday?.
I’m still working on it…I’ll post when I’ve got it done.

–Jeremy

On 1/2/07, Kenosis removed_email_address@domain.invalid wrote:

<…>
For fixed holidays, sure - I think that’s what Date::Calc does (i.e.
for suddenly announced national “holidays”, like today happens to be -
doh!

Ken


My free Ruby e-book:
http://www.humblelittlerubybook.com/book/

My blogs:
http://www.mrneighborly.com/
http://www.rubyinpractice.com/


#13

On Jan 2, 2007, at 2:37 PM, Jeremy McAnally wrote:

Well, the way I’m working it out is like AR’s dynamic finders. It
will have a few groups of dates hardcoded (like national holidays and
such), but then you can give it new groups in the form hashes of
arrays of dates with named “work_holidays” or “surprise_offdays” and
then call the method like is_a_work_holiday? or is_a_surprise_offday?.
I’m still working on it…I’ll post when I’ve got it done.

–Jeremy

Sounds neat. Just please bottom post when replying :slight_smile:
-Mat


#14

On Jan 2, 2007, at 2:55 PM, Daniel B. wrote:

national holidays IF I’m using Date#cweek correctly and reliably here:

require ‘date’

class Date
def thanksgiving?
month == 11 && wday == 4 && cweek == 3
end

I think it would be cweek == 4, but I like the idea. This particular
implementation doesn’t seem very extensible. Not sure what would be
the best way to define some sort of custom holidays file that could
be read by a gem… Procs in a hash comes to mind.
-Mat


#15

Mat S. wrote:

Actually, once I took a stab at it, I think it’s fairly easy for the
implementation doesn’t seem very extensible. Not sure what would be
the best way to define some sort of custom holidays file that could
be read by a gem… Procs in a hash comes to mind.

Yeah, I think you’re right about the cweek. You’re also right about
this implementation not being very extensible.

On a side note, I was thinking of something like this for a theoretical
layout:

lib/
date/
holiday/
us.rb
uk.rb
jp.rb

And then the end user would simply do “require ‘date/holiday/us’” to
get the US holidays, etc. I’m not certain, though.

Regards,

Dan

PS - The Date#national_holiday? method I posted is wrong. There should
be “||” not “&&” between the method checks.


#16

Daniel B. wrote:

record of which dates are holidays in a given year. It can be a
can come up with a general algorithm for “3rd Thursday in November”,
etc. I’ll bet the Rails folks already have something, but I haven’t
looked.

Regards,

Dan

I have an old copy of Computer Language that includes the C source for
Julian dates. One of the functions is the determination of Easter for
any given year. If you are interested in just that algorithm or the
entire code let me know. I assume that the determination of
Thanksgiving (for the US) would be trivial from there.
The only other real problem is that some states, Nevada for example,
change at least one of the holidays, where the state doesn’t take
Columbus day off but takes off October 31st – state admission day.


#17

Jeremy McAnally wrote:

Well, the way I’m working it out is like AR’s dynamic finders. It
will have a few groups of dates hardcoded (like national holidays and
such), but then you can give it new groups in the form hashes of
arrays of dates with named “work_holidays” or “surprise_offdays” and
then call the method like is_a_work_holiday? or is_a_surprise_offday?.
I’m still working on it…I’ll post when I’ve got it done.

Actually, once I took a stab at it, I think it’s fairly easy for the
national holidays IF I’m using Date#cweek correctly and reliably here:

require ‘date’

class Date
def thanksgiving?
month == 11 && wday == 4 && cweek == 3
end

def christmas?
month == 12 && day == 25
end

def new_years?
month == 1 && day == 1
end

alias new_year new_years
alias new_years_day new_years

def memorial_day?
if month == 5 && wday == 1 && cweek == 5
end

def independence_day?
month == 7 && day == 4
end

alias fourth_of_july? independence_day?

def national_holiday?
new_years? && memorial_day? && independence_day? && thanksgiving?
&&
christmas?
end
end

How’s that?

Regards,

Dan


#18

On Wed, 2007-01-03 at 11:38 +0900, Jeremy McAnally wrote:

Okay, I got the code done. I just need to create lists of holidays
now. I can do the U.S. holidays (if I need any help algorithm-wise,
I’ll let you guys know…), but I have no clue about UK or anyone
else’s holidays. Anyone from another locality care to englighten me?

I called it “special_days” because Im hoping it can be used for
purposes other than just holidays (birthdays? patch_days? The
possibilities are approaching limitless!).

RubyConf Days?


#19

Okay, I got the code done. I just need to create lists of holidays
now. I can do the U.S. holidays (if I need any help algorithm-wise,
I’ll let you guys know…), but I have no clue about UK or anyone
else’s holidays. Anyone from another locality care to englighten me?

I called it “special_days” because Im hoping it can be used for
purposes other than just holidays (birthdays? patch_days? The
possibilities are approaching limitless!).

I’m working on getting a gem together right now…

–Jeremy

On 1/2/07, Daniel B. removed_email_address@domain.invalid wrote:

Repeat again for Memorial Day, July 4th, Thanksgiving, and Christmas.

  • Dan

[1] http://search.cpan.org/~stbey/Date-Calc-5.4/Calendar.pod
[2]
http://search.cpan.org/~stbey/Date-Calc-5.4/lib/Date/Calendar/Profiles.pod
[3]
http://search.cpan.org/~jonasbn/Date-Holidays-0.08/lib/Date/Holidays.pm


My free Ruby e-book:
http://www.humblelittlerubybook.com/book/

My blogs:
http://www.mrneighborly.com/
http://www.rubyinpractice.com/


#20

No! I insist that you top post!*

Oh, and for some actual content:
http://en.wikipedia.org/wiki/Computus#Algorithms
Good luck with that.

Martin F. had an article/series of articles on building a DSL for
recurring dates. You might want to investigate.

Devin

Mat S. wrote:

–Jeremy

Sounds neat. Just please bottom post when replying :slight_smile:
-Mat

  • I’m joking, mostly. I use Thunderbird, ATM, so top posts are much more
    convenient for me. I know, I know, majority rules… just… trim, if
    you bottom post.

Devin