ByStar
ByStar (by_*) allows you easily and reliably query ActiveRecord and Mongoid objects based on time.
Examples
Post.by_year(2013) # all posts in 2013
Post.before(Date.today) # all posts for before today
Post.yesterday # all posts for yesterday
Post.between_times(Time.zone.now - 3.hours, # all posts in last 3 hours
Time.zone.now)
@post.next # next post after a given post
Installation
Install this gem by adding this to your Gemfile:
gem 'by_star', git: 'https://github.com/radar/by_star'
Then run bundle install
If you are using ActiveRecord, you're done!
Mongoid users, please include the Mongoid::ByStar module for each model you wish to use the functionality. This is the convention among Mongoid plugins.
class MyModel
include Mongoid::Document
include Mongoid::ByStar
Finder Methods
Base Scopes
ByStar adds the following finder scopes (class methods) to your model to query time ranges.
These accept a Date
, Time
, or DateTime
object as an argument, which defaults to Time.zone.now
if not specified:
Scope | Meaning |
---|---|
between_times(start_time, end_time) |
Finds all records occurring between two given times. |
between_dates(start_date, end_date) |
Finds all records occurring between two given dates, from beginning of start_date until end of end_date. |
before(end_time) |
Finds all records occurring before the given time. |
after(start_time) |
Finds all records occurring after the given time. |
at_time(time) |
Finds all records occurring exactly at the given time, or which overlap the time in the case of "timespan"-type object (see below) |
between_times
and between_dates
supports alternate argument forms:
between_times(Range)
between_times(Array)
between_times(start_time, nil)
- same asafter(start_time)
between_times(nil, end_time)
- same asbefore(end_time)
Time Range Scopes
ByStar adds additional shortcut scopes based on commonly used time ranges. See sections below for detailed argument usage of each:
Scope | Meaning |
---|---|
by_day |
Query by a given date. |
by_week |
Allows zero-based week value from 0 to 52. |
by_cweek |
Allows one-based week value from 1 to 53. |
by_weekend |
Saturday and Sunday only of the given week. |
by_fortnight |
A two-week period, with the first fortnight of the year beginning on 1st January. |
by_month |
Query by month. Allows integer arg, e.g. 11 for November. |
by_calendar_month |
Month as it appears on a calendar; days form previous/following months which are part of the first/last weeks of the given month. |
by_quarter |
3-month intervals of the year. |
by_year |
Query by year. Allows integer arg, e.g. 2017 . |
Relative Scopes
ByStar also adds scopes which are relative to the current time.
Note the past_*
and next_*
methods represent a time distance from current time (Time.zone.now
),
and do not strictly end/begin evenly on a calendar week/month/year (unlike by_*
methods which do.)
Scope | Meaning |
---|---|
today |
Finds all occurrences on today's date. |
yesterday |
Finds all occurrences on yesterday's date. |
tomorrow |
Finds all occurrences on tomorrow's date. |
past_day |
Prior 24-hour period from current time. |
past_week |
Prior 7-day period from current time. |
past_fortnight |
Prior 14-day period from current time. |
past_month |
Prior 30-day period from current time. |
past_year |
Prior 365-day period from current time. |
next_day |
Subsequent 24-hour period from current time. |
next_week |
Subsequent 7-day period from current time. |
next_fortnight |
Subsequent 14-day period from current time. |
next_month |
Subsequent 30-day period from current time. |
next_year |
Subsequent 365-day period from current time. |
Superlative Finders
Find the oldest or newest records. Returns an object instance (not a relation):
newest
oldest
Instance Methods
In addition, ByStar adds instance methods to return the next / previous record in the timewise sequence. Returns an object instance (not a relation):
object.next
object.previous
Kernel Extensions
ByStar extends the kernel Date
, Time
, and DateTime
objects with the following instance methods,
which mirror the ActiveSupport methods beginning_of_day
, end_of_week
, etc:
beginning_of_weekend
end_of_weekend
beginning_of_fortnight
end_of_fortnight
beginning_of_calendar_month
end_of_calendar_month
Lastly, ByStar aliases Rails 3 Date#to_time_in_current_zone
to the Rails 4 syntax #in_time_zone
, if it has not already been defined.
Usage
Setting the Query Field
By default, ByStar assumes you will use the created_at
field to query objects by time.
You may specify an alternate field on all query methods as follows:
Post.by_month("January", field: :updated_at)
Alternatively, you may set a default in your model using the by_star_field
macro:
class Post < ActiveRecord::Base
by_star_field :updated_at
end
Scoping the Query
All ByStar methods (except oldest
, newest
, previous
, next
) return an ActiveRecord::Relation
(or Mongoid::Criteria
) which can be daisy-chained with other scopes/finder methods:
Post.by_month.your_scope
Post.by_month(1).include(:tags).where("tags.name" => "ruby")
Want to count records? Simple:
Post.by_month.count
Timezone Handling
ByStar date-range finders will use value of Time.zone
to evaluate the args.
This may cause unexpected behavior when use Time values in timezones other than Time.zone
.
Time.zone = 'Australia/Sydney'
Post.by_day('2020-04-05 18:00:00 EST')
#=> Returns Apr 6th, 0:00 until Apr 6th, 23:59 in Sydney timezone.
:offset
Option
All ByStar finders support an :offset
option which is applied to time period of the query condition.
This is useful in cases where the daily cycle occurs at a time other than midnight.
For example, if you'd like to find all Posts from 9:00 on 2014-03-05 until 8:59:59.999 on 2014-03-06, you can do:
Post.by_day('2014-03-05', offset: 9.hours)
Note: When passing offset
in date finders, it will set the hour, minute, and second on the queried date in order to properly handle DST transitions. Example:
Time.zone = 'Australia/Sydney'
Post.by_day('2020-04-05', offset: 9.hours)
#=> Returns Apr 5th, 09:00 until Apr 6th, 08:59
Timespan Objects
If your object has both a start and end time, you may pass both params to by_star_field
:
by_star_field :start_time, :end_time
By default, ByStar queries will return all objects whose range has any overlap within the desired period (permissive):
MultiDayEvent.by_month("January")
#=> returns MultiDayEvents that overlap in January,
# even if they start in December and/or end in February
Timespan Objects: #at_time
To find all instances of a timespan object which contain a specific time:
Post.at_time(time)
This can be useful to find all currently active instances. Note that object instances which start
exactly at the given time
will be included in the result, but instances that end exactly at the given
time
will not be.
Timespan Objects: :strict
Option
If you'd like to confine results to only those both starting and ending within the given range, use the :strict
option:
MultiDayEvent.by_month("January", :strict => true)
#=> returns MultiDayEvents that both start AND end in January
Timespan Objects: Database Indexing and :index_scope
Option
In order to ensure query performance on large dataset, you must add an index to the query field (e.g. "created_at") be indexed. ByStar does not define indexes automatically.
Database indexes require querying a range query on a single field, i.e. start_time >= X and start_time <= Y
.
If we use a single-sided query, the database will iterate through all items either from the beginning or until the end of time.
This poses a challenge for timespan-type objects which have two fields, i.e. start_time
and end_time
.
There are two cases to consider:
1) Timespan with :strict
option, e.g. start_time >= X and end_time <= Y
.
Given that this gem requires start_time >= end_time
, we add the converse constraint start_time <= Y and end_time >= X
to ensure both fields are double-sided, i.e. an index can be used on either field.
2) Timespan without :strict
option, e.g. "start_time < Y and end_time > X".
Here we need to add a condition start_time >= X
to ensure start_time
is bounded on both sides.
To achieve this, we allow an :index_scope
option which is the minimum "strict" bound on the querying range,
in other words, it is an assumption about the maximum timespan of objects.
:index_scope
supports multiple value types:
:index_scope Value |
Meaning |
---|---|
nil or false |
No constraint set; query will be one-sided (default, but not recommended) |
Date or Time , etc. |
A fixed point in time |
ActiveSupport::Duration (e.g. 1.month ) |
The duration value will be subtracted from the start of the range. In other words, a value of 1.month would imply the longest possible object in the database is no longer than 1.month . |
Numeric |
Will be converted to seconds, then handled the same as ActiveSupport::Duration |
:beginning_of_day (Symbol literal) |
|
Proc<Range, Hash(options)> |
A proc which evaluates to one of the above types. Args are (start_time, end_time, options) |
An example settings of :index_scope
:
# The maximum possible object length is 5 hours.
by_star index_scope: 5.hours
# Objects are guaranteed to start within the same month, with some offset.
by_star index_scope: ->(start_time, end_time, ){ start_time.beginning_of_month + ([:offset] || 0) }
# The maximum possible object length half the range being queried.
by_star index_scope: ->(start_time, end_time, ){ ((start_time - end_time)*0.5).seconds }
Chronic Support
If Chronic gem is present, it will be used to parse natural-language date/time
strings in all ByStar finder methods. Otherwise, the Ruby Time.parse
kernel method will be used as a fallback.
As of ByStar 2.2.0, you must explicitly include gem 'chronic'
into your Gemfile in order to use Chronic.
Advanced Usage
between_times
To find records between two times:
Post.between_times(time1, time2)
You use a Range like so:
Post.between_times(time1..time2)
Also works with dates - WARNING: there are currently some caveats see Issue #49:
Post.between_times(date1, date2)
It will query records from date1
(00:00:00 Hrs) until date2
(23:59:59 Hrs).
before and after
To find all posts before / after the current time:
Post.before
Post.after
To find all posts before certain time or date:
Post.before(Date.today + 2)
Post.after(Time.now + 5.days)
You can also pass a string:
Post.before("next tuesday")
For Time-Range type objects, only the start time is considered for before
and after
.
previous and next
To find the prior/subsequent record to a model instance, previous
/next
on it:
Post.last.previous
Post.first.next
You can specify a field also:
Post.last.previous(field: "published_at")
Post.first.next(field: "published_at")
For Time-Range type objects, only the start time is considered for previous
and next
.
by_year
To find records from the current year, simply call the method without any arguments:
Post.by_year
To find records based on a year you can pass it a two or four digit number:
Post.by_year(09)
This will return all posts in 2009, whereas:
Post.by_year(99)
will return all the posts in the year 1999.
You can also specify the full year:
Post.by_year(2009)
Post.by_year(1999)
by_month
If you know the number of the month you want:
Post.by_month(1)
This will return all posts in the first month (January) of the current year.
If you like being verbose:
Post.by_month("January")
This will return all posts created in January of the current year.
If you want to find all posts in January of last year just do
Post.by_month(1, year: 2007)
or
Post.by_month("January", year: 2007)
This will perform a find using the column you've specified.
If you have a Time object you can use it to find the posts:
Post.by_month(Time.local(2012, 11, 24))
This will find all the posts in November 2012.
by_calendar_month
Finds records for a given month as shown on a calendar. Includes all the results of by_month
, plus any results which fall in the same week as the first and last of the month. Useful for working with UI calendars which show rows of weeks.
Post.by_calendar_month
Parameter behavior is otherwise the same as by_month
. Also, :start_day
option is supported to specify the start day of the week (:monday
, :tuesday
, etc.)
by_fortnight
Fortnight numbering starts at 0. The beginning of a fortnight is Monday, 12am.
To find records from the current fortnight:
Post.by_fortnight
To find records based on a fortnight, you can pass in a number (representing the fortnight number) or a time object:
Post.by_fortnight(18)
This will return all posts in the 18th fortnight of the current year.
Post.by_fortnight(18, year: 2012)
This will return all posts in the 18th fortnight week of 2012.
Post.by_fortnight(Time.local(2012,1,1))
This will return all posts from the first fortnight of 2012.
by_week and by_cweek
Week numbering starts at 0, and cweek numbering starts at 1 (same as Date#cweek
). The beginning of a week is as defined in ActiveSupport#beginning_of_week
, which can be configured.
To find records from the current week:
Post.by_week
Post.by_cweek # same result
This will return all posts in the 37th week of the current year (remember week numbering starts at 0):
Post.by_week(36)
Post.by_cweek(37) # same result
This will return all posts in the 37th week of 2012:
Post.by_week(36, year: 2012)
Post.by_cweek(37, year: 2012) # same result
This will return all posts in the week which contains Jan 1, 2012:
Post.by_week(Time.local(2012,1,1))
Post.by_cweek(Time.local(2012,1,1)) # same result
You may pass in a :start_day
option (:monday
, :tuesday
, etc.) to specify the starting day of the week. This may also be configured in Rails.
by_weekend
If the time passed in (or the time now is a weekend) it will return posts from 0:00 Saturday to 23:59:59 Sunday. If the time is a week day, it will show all posts for the coming weekend.
Post.by_weekend(Time.now)
by_day and today
To find records for today:
Post.by_day
Post.today
To find records for a certain day:
Post.by_day(Time.local(2012, 1, 1))
You can also pass a string:
Post.by_day("next tuesday")
This will return all posts for the given day.
by_quarter
Finds records by 3-month quarterly period of year. Quarter numbering starts at 1. The four quarters of the year begin on Jan 1, Apr 1, Jul 1, and Oct 1 respectively.
To find records from the current quarter:
Post.by_quarter
To find records based on a quarter, you can pass in a number (representing the quarter number) or a time object:
Post.by_quarter(4)
This will return all posts in the 4th quarter of the current year.
Post.by_quarter(2, year: 2012)
This will return all posts in the 2nd quarter of 2012.
Post.by_week(Time.local(2012,1,1))
This will return all posts from the first quarter of 2012.
Version Support
ByStar is tested against the following versions:
- Ruby 2.0.0+
- Rails/ActiveRecord 3.2+
- Mongoid 3.1+
Note that ByStar automatically adds the following version compatibility shims:
- ActiveSupport 3.x: Add
Time/Date/DateTime#in_time_zone
(as an alias to#to_time_in_current_zone
) for compatibility with Rails 4+. - Mongoid 3.x: Adds
Criteria#reorder
method from Mongoid 4.
Testing
Test Setup
Specify a database by supplying a DB
environmental variable:
bundle exec rake spec DB=sqlite
You can also take an ORM-specific test task for a ride:
bundle exec rake spec:active_record
Have an Active Record or Mongoid version in mind? Set the environment variables
ACTIVE_RECORD_VERSION
and MONGOID_VERSION
to a version of your choice. A
version number provided will translate to ~> VERSION
, and the string master
will grab the latest from Github.
# Update your bundle appropriately...
ACTIVE_RECORD_VERSION=4.0.0 MONGOID_VERSION=master bundle update
# ...then run the specs
ACTIVE_RECORD_VERSION=4.0.0 MONGOID_VERSION=master bundle exec rpsec spec
Test Implementation
ByStar tests use TimeCop to lock the system Time.now
at Jan 01, 2014, and seed
objects with fixed dates according to spec/fixtures/shared/seeds.rb
.
Note that the timezone is randomized on each run to shake-out timezone related quirks.
Collaborators
ByStar is actively maintained by Ryan Bigg (radar) and Johnny Shields (johnnyshields)
Thank you to the following people:
- Thomas Sinclair for the original bump for implementing ByStar
- Ruby on Rails for their support
- Mislav Marohnic
- August Lilleas (leethal)
- gte351s
- Sam Elliott (lenary)
- The creators of the Chronic gem
- Erik Fonselius
- Johnny Shields (johnnyshields)