Dtg

DTG is a ruby gem to convert Time objects into DTG format.

A DTG is a DateTimeGroup which is used in the military to save time. DTG are saved in the format DDHHMML MMM YY, where D is day, H is hour, L is letter, M is month, and Y is year. The Month is the 3 character representation such as JAN for January, MAY for May, DEC for December and so on. Year is only the last two digits of the year e.g. 2019 is just 19. The letter is the zone code such as W for whiskey which is HST, Z for zulu which is GMT, A-Z are the zones used.

DTG integrates natively with the DateTime, Time, and ActiveSupport::TimeWithZone classes in Ruby/Rails and is callable on all Time objects. DTG returns a visually formatted dtg converted based on knolwedge of the zone of the object and the intended zone. It is also respective of daylight savings time of your objects zone and its intended zone.

DTG is the military acronym referring to what is also called nautical or maritime time zones. These zones are mapped across the world from A-Z not including J as J references the local timezone of yourself.

Table of Contents

1. DTG
2. Table of Contents
3. Usage
   1. DTG Zones
   2. DTG Zone Map
4. Installation
5. Testing
6. Compatability
7. Problems
8. Contributing
9. License

Usage

DTG implements the method to_dtg into the Time class and is fully compatible with all Time objects(DateTime, Time, and TimeWithZone have been tested, custom objects should also function the same as long as their properties emulate that of the former).

To use:

TIMEOBJECT.to_dtg

and it will return the time object as a string in the zulu timezone in dtg format.

For other DTG formats:

TIMEOBJECT.to_dtg(:zone)

where zone is any single letter symbol A-Z, capital or lower case and it will return the time object as a string in the zone format.

USAGE NOTES: Ensure that in your application or before using this gems methods(convert/to_dtg) which calls the in_time_zone method, you must set Time.zone = "yourtimezone(HST for me)". Otherwise in_time_zone will be called and return nil:NilObject due to Time.zone returning nil(ActiveSupport thing). Rails has a place in the application configuration to set the Time.zone before startup.

DTG Zones

• A: Alpha Time: UTC +01:00 (Paris, France)
• B: Bravo Time: UTC +02:00 (Athens, Greece)
• C: Charlie Time: UTC +03:00 (Moscow, Russia)
• D: Delta Time: UTC +04:00 (Kabul, Afghanistan)
• E: Echo Time: UTC +05:00 (New Delhi, India)
• F: Foxtrot Time: UTC +06:00 (Dhanka, Bangladesh)
• G: Golf Time: UTC +07:00 (Bangkok, Thailand)
• H: Hotel Time: UTC +08:00 (Beijing, China)
• I: India Time: UTC +09:00 (Tokyo, Japan)
• J: Juliet Time: (Local Time Zone)
• K: Kilo Time: UTC +10:00 (Sydney, Australia)
• L: Lima Time: UTC +11:00 (Honiara, Solomon Islands)
• M: Mike Time: UTC +12:00 (Wellington, New Zealand)
• N: November Time: UTC -01:00 (Azores)
• O: Oscar Time: UTC -02:00 (Gothab, Greenland)
• P: Papa Time: UTC -03:00 (Buenos Aires, Argentina)
• Q: Quebec Time: UTC -04:00 (Halifax, Nova Scotia)
• R: Romeo Time: UTC -05:00 (New York, NY United States)
• S: Sierra Time: UTC -06:00 (Dallas, TX United States)
• T: Tango Time: UTC -07:00 (Denver, CO United States)
• U: Uniform Time: UTC -08:00 (Los Angeles, CA United States)
• V: Victor Time: UTC -09:00 (Juneau, AK United States)
• W: Whiskey Time: UTC -10:00 (Honolulu, HI United States)
• X: X-Ray Time: UTC -11:00 (Nome, AK United States)
• Y: Yankee Time: UTC -12:00 (Suva, Fiji)
• Z: Zulu Time: UTC +-00:00 (Greenwich, England)

DTG Zone Map

Installation

Add this line to your application's Gemfile:

gem 'dtg'

And then execute:

bundle install

Or install it yourself as:

cd dtg
gem build dtg
gem install dtg

Testing

If you would like to test this gem before adding it to your project to see it's functionality, follow these steps:

1. Clone the repository

git clone https://github.com/SolarisFlare/dtg

2. cd into the project

3. Build the gem

gem build dtg

4. Install the gem

gem install dtg

5. Start the ruby console

irb

OR

the ruby running console of your choice (pry, rails console / rails c, ...)

6. Require it to load it into the console (only necessary for irb, others like rails should usually load automatically but it doesn't hurt if it doesn't work!)

require 'dtg'

7. Test away

#<Tested in irb console and rails console, also works in Pry console>

y = Time.zone.now
y.dtg
y = Time.zone.now.to_dtg(:j)
y

x = Time.now
x.dtg
x.to_dtg(:j)
x.to_dtg(:J)
x.to_dtg
x.to_dtg(:z)
x.to_dtg(:Z)
x.to_dtg(:W)
DateTimeGroup.from_dtg(x.to_dtg(:m))

z = DateTime.now
z.dtg
DateTimeGroup.convert(z.to_dtg, :w)
z.to_dtg :w
z.convert :w
z.to_dtg :c
DateTimeGroup.parse z

Time.now.to_dtg(:a)
DateTime.now.to_dtg :Q
Time.zone.now.to_dtg L.to_sym

Note: The .dtg method will return a string naming the type of the object you called it on and can therefore be used to verify if the gem has successfully natively integrated with Ruby/Rails(should fail if not). I included this for testing purposes to check that the right modules were being loaded with DTG and have run into no load failures but for peace of mind I left it in in case you want to see for yourself.

Compatability

All versions of DTG are 100% compatible with all versions of rails so long as date(DateTime) time(Time) and TimeWithZone(ActiveSupport::TimeWithZone) are present otherwise the features associated with those classes will not be available. The gem will still function without them as I have discovered through and the features associated with the missing classes will just not be there, however, attempting to use the features with one of the non-existant classes it integrates into will most likely error or cause strange behaviours so I recommend only using with the classes your application contains(i.e. do not attempt to use ActiveSupport::TimeWithZone with pure ruby unless you include it somehow in your application), luckily, all rails applications contain all 3 classes and any ruby application contains Time by default and as of lately, also contains date(I think) although the TimeWithZone will most likely not be there since it is from activesupport which is part of the rails gem.

This Gem now includes the necessary libraries from active_support and date to work without rails. It is 100% compatible with all versions of rails/active_support. If you do not set Time.zone to a valid zone(many ways to do this, I recommend the 3 char code such as HST for Hawaiian Standard Time when you set your timezone to ensure proper zone coverage if your zone does daylight savings time or summer time. DateTimeGroup#convert and DateTimeGroup#to_dtg(which calls convert) will result in nil:NilObject if Time.zone is not set before using them. Works with irb/pry/ruby/rails and probably more that I haven't tested yet. Enjoy!

Problems

DTG relies upon time objects that have timezone set either as Time.zone or as the default offset recorded. I recommend setting the application timezone in the application.rb configuration file so that dtg works automatically on any generated time objects otherwise it will convert all time objects from UTC +00:00 which is the rails default zone (Etc/UTC) and therefore can provide unintended results. TimeWithZone is different and therefore is a Time with offset and with zone. Therefore without data loss, you can convert from TimeWithZone to DateTime or Time and maintain the same time, however, you may lose the zone code but the offset will be kept and the zone code can be recovered based on this offset but certain zones that follow daylight savings time may lose their savings-ness and will no longer spring forward or backward if converted. You also cannot truly convert from J (Juliet or local time) to any other dtg zone. This is because DTG store their zone as an offset letter code, whereas the code J is the local time (but what is local?) and the only way to know the local time would be to take it from the time of the machine doing the conversion! However, what if I emailed you something in J, there would be no way to tell what its time code actually is because you could insert it into a database and would then not know what "local" is for it. Luckily, people only use J rarely or in small circumstances. Almost everything sent is first changed to Z and everyone knows what their local time is in Z and convert it for internal documents. If you read old historical documents that use the dtg zone codes, you can see this. I included a parse method so you can imlpement your own parsers/formatters from a dtg in case you run into J codes (hopefully never).

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/dtg. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

If you want to contribute please let me know though either an email or you can just submit a pull request to add anything or open an issue and I can look through it with you!

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Dtg project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.