module Sequel::Timezones

  1. lib/sequel/core.rb
  2. lib/sequel/timezones.rb
  3. show all

Sequel doesn’t pay much attention to timezones by default, but you can set it to handle timezones if you want. There are three separate timezone settings:

All three timezones have getter and setter methods. You can set all three timezones to the same value at once via Sequel.default_timezone=.

The only timezone values that are supported by default are :utc (convert to UTC), :local (convert to local time), and nil (don’t convert). If you need to convert to a specific timezone, or need the timezones being used to change based on the environment (e.g. current user), you need to use the named_timezones extension (and use DateTime as the datetime_class). Sequel also ships with a thread_local_timezones extensions which allows each thread to have its own timezone values for each of the timezones.

Public Instance Aliases

orig_require -> require

Alias of original require method, as Sequel.require does a relative require for backwards compatibility.


application_timezone [R]

The timezone you want the application to use. This is the timezone that incoming times from the database and typecasting are converted to.

convert_two_digit_years [RW]

Sequel converts two digit years in Dates and DateTimes by default, so 01/02/03 is interpreted at January 2nd, 2003, and 12/13/99 is interpreted as December 13, 1999. You can override this to treat those dates as January 2nd, 0003 and December 13, 0099, respectively, by:

Sequel.convert_two_digit_years = false
database_timezone [R]

The timezone for storage in the database. This is the timezone to which Sequel will convert timestamps before literalizing them for storage in the database. It is also the timezone that Sequel will assume database timestamp values are already in (if they don’t include an offset).

datetime_class [RW]

Sequel can use either Time or DateTime for times returned from the database. It defaults to Time. To change it to DateTime:

Sequel.datetime_class = DateTime

Note that Time and DateTime objects have a different API, and in cases where they implement the same methods, they often implement them differently (e.g. + using seconds on Time and days on DateTime).

single_threaded [RW]

Set whether Sequel is being used in single threaded mode. By default, Sequel uses a thread-safe connection pool, which isn’t as fast as the single threaded connection pool, and also has some additional thread safety checks. If your program will only have one thread, and speed is a priority, you should set this to true:

Sequel.single_threaded = true
typecast_timezone [R]

The timezone that incoming data that Sequel needs to typecast is assumed to be already in (if they don’t include an offset).

Public Instance methods


Convert the given Time/DateTime object into the database timezone, used when literalizing objects in an SQL string.

[show source]
   # File lib/sequel/timezones.rb
50 def application_to_database_timestamp(v)
51   convert_output_timestamp(v, Sequel.database_timezone)
52 end

Returns true if the passed object could be a specifier of conditions, false otherwise. Currently, Sequel considers hashes and arrays of two element arrays as condition specifiers.

Sequel.condition_specifier?({}) # => true
Sequel.condition_specifier?([[1, 2]]) # => true
Sequel.condition_specifier?([]) # => false
Sequel.condition_specifier?([1]) # => false
Sequel.condition_specifier?(1) # => false
[show source]
   # File lib/sequel/core.rb
83 def condition_specifier?(obj)
84   case obj
85   when Hash
86     true
87   when Array
88     !obj.empty? && !obj.is_a?(SQL::ValueList) && obj.all?{|i| i.is_a?(Array) && (i.length == 2)}
89   else
90     false
91   end
92 end
connect(*args, &block)

Creates a new database object based on the supplied connection string and optional arguments. The specified scheme determines the database class used, and the rest of the string specifies the connection options. For example:

DB = Sequel.connect('sqlite:/') # Memory database
DB = Sequel.connect('sqlite://blog.db') # ./blog.db
DB = Sequel.connect('sqlite:///blog.db') # /blog.db
DB = Sequel.connect('postgres://user:password@host:port/database_name')
DB = Sequel.connect('sqlite:///blog.db', max_connections: 10)

You can also pass a single options hash:

DB = Sequel.connect(adapter: 'sqlite', database: './blog.db')

If a block is given, it is passed the opened Database object, which is closed when the block exits. For example:

Sequel.connect('sqlite://blog.db'){|db| puts db[:users].count}

If a block is not given, a reference to this database will be held in Sequel::DATABASES until it is removed manually. This is by design, and used by Sequel::Model to pick the default database. It is recommended to pass a block if you do not want the resulting Database object to remain in memory until the process terminates, or use the keep_reference: false Database option.

For details, see the “Connecting to a Database” guide. To set up a primary/replica or sharded database connection, see the “Primary/Replica Database Configurations and Sharding” guide.

[show source]
    # File lib/sequel/core.rb
123 def connect(*args, &block)
124   Database.connect(*args, &block)
125 end
convert_exception_class(exception, klass)

Convert the exception to the given class. The given class should be Sequel::Error or a subclass. Returns an instance of klass with the message and backtrace of exception.

[show source]
    # File lib/sequel/core.rb
136 def convert_exception_class(exception, klass)
137   return exception if exception.is_a?(klass)
138   e ="#{exception.class}: #{exception.message}")
139   e.wrapped_exception = exception
140   e.set_backtrace(exception.backtrace)
141   e
142 end
convert_output_timestamp(v, output_timezone)

Converts the object to the given output_timezone.

[show source]
   # File lib/sequel/timezones.rb
55 def convert_output_timestamp(v, output_timezone)
56   if output_timezone
57     if v.is_a?(DateTime)
58       case output_timezone
59       when :utc
60         v.new_offset(0)
61       when :local
62         v.new_offset(local_offset_for_datetime(v))
63       else
64         convert_output_datetime_other(v, output_timezone)
65       end
66     else
67       case output_timezone
68       when :utc
69         v.getutc
70       when :local
71         v.getlocal
72       else
73         convert_output_time_other(v, output_timezone)
74       end
75     end
76   else
77     v
78   end
79 end
convert_timestamp(v, input_timezone)

Converts the given object from the given input timezone to the application_timezone using convert_input_timestamp and convert_output_timestamp.

[show source]
   # File lib/sequel/timezones.rb
84 def convert_timestamp(v, input_timezone)
85   if v.is_a?(Date) && !v.is_a?(DateTime)
86     # Dates handled specially as they are assumed to already be in the application_timezone
87     if datetime_class == DateTime
88       DateTime.civil(v.year, v.month,, 0, 0, 0, application_timezone == :local ? Rational(Time.local(v.year, v.month,, 86400) : 0)
89     else
90       Time.public_send(application_timezone == :utc ? :utc : :local, v.year, v.month,
91     end
92   else
93     convert_output_timestamp(convert_input_timestamp(v, input_timezone), application_timezone)
94   end
95 rescue InvalidValue
96   raise
97 rescue => e
98   raise convert_exception_class(e, InvalidValue)
99 end

Assume the core extensions are not loaded by default, if the core_extensions extension is loaded, this will be overridden.

[show source]
    # File lib/sequel/core.rb
129 def core_extensions?
130   false
131 end

The current concurrency primitive, Thread.current by default.

[show source]
    # File lib/sequel/core.rb
145 def current
146   Thread.current
147 end

Convert the given object into an object of Sequel.datetime_class in the application_timezone. Used when converting datetime/timestamp columns returned by the database.

[show source]
    # File lib/sequel/timezones.rb
104 def database_to_application_timestamp(v)
105   convert_timestamp(v, Sequel.database_timezone)
106 end

Sets the database, application, and typecasting timezones to the given timezone.

[show source]
    # File lib/sequel/timezones.rb
109 def default_timezone=(tz)
110   self.database_timezone = tz
111   self.application_timezone = tz
112   self.typecast_timezone = tz
113 end

The elapsed seconds since the given timer object was created. The timer object should have been created via Sequel.start_timer.

[show source]
    # File lib/sequel/core.rb
335 def elapsed_seconds_since(timer)
336   start_timer - timer
337 end

Load all Sequel extensions given. Extensions are just files that exist under sequel/extensions in the load path, and are just required.

In some cases, requiring an extension modifies classes directly, and in others, it just loads a module that you can extend other classes with. Consult the documentation for each extension you plan on using for usage.

Sequel.extension(:core_extensions, :named_timezones)
[show source]
    # File lib/sequel/core.rb
157 def extension(*extensions)
158   extensions.each{|e| orig_require("sequel/extensions/#{e}")}
159 end

The exception classed raised if there is an error parsing JSON. This can be overridden to use an alternative json implementation.

[show source]
    # File lib/sequel/core.rb
163 def json_parser_error_class
164   JSON::ParserError
165 end
object_to_json(obj, *args, &block)

Convert given object to json and return the result. This can be overridden to use an alternative json implementation.

[show source]
    # File lib/sequel/core.rb
169 def object_to_json(obj, *args, &block)
170   obj.to_json(*args, &block)
171 end

Parse the string as JSON and return the result. This can be overridden to use an alternative json implementation.

[show source]
    # File lib/sequel/core.rb
175 def parse_json(json)
176   JSON.parse(json, :create_additions=>false)
177 end
recursive_map(array, converter)

Convert each item in the array to the correct type, handling multi-dimensional arrays. For each element in the array or subarrays, call the converter, unless the value is nil.

[show source]
    # File lib/sequel/core.rb
193 def recursive_map(array, converter)
194 do |i|
195     if i.is_a?(Array)
196       recursive_map(i, converter)
197     elsif !i.nil?
199     end
200   end
201 end
require(files, subdir=nil)

For backwards compatibility only. require_relative should be used instead.

[show source]
    # File lib/sequel/core.rb
204 def require(files, subdir=nil)
205   # Use Kernel.require_relative to work around JRuby 9.0 bug
206   Array(files).each{|f| Kernel.require_relative "#{"#{subdir}/" if subdir}#{f}"}
207 end

Splits the symbol into three parts, if symbol splitting is enabled (not the default). Each part will either be a string or nil. If symbol splitting is disabled, returns an array with the first and third parts being nil, and the second part beind a string version of the symbol.

For columns, these parts are the table, column, and alias. For tables, these parts are the schema, table, and alias.

[show source]
    # File lib/sequel/core.rb
216 def split_symbol(sym)
217   unless v = Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym]}
218     if split_symbols?
219       v = case s = sym.to_s
220       when /\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/
221         [$1.freeze, $2.freeze, $3.freeze].freeze
222       when /\A((?:(?!___).)+)___(.+)\z/
223         [nil, $1.freeze, $2.freeze].freeze
224       when /\A((?:(?!__).)+)__(.+)\z/
225         [$1.freeze, $2.freeze, nil].freeze
226       else
227         [nil, s.freeze, nil].freeze
228       end
229     else
230       v = [nil,sym.to_s.freeze,nil].freeze
231     end
232     Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym] = v}
233   end
234   v
235 end

Setting this to true enables Sequel’s historical behavior of splitting symbols on double or triple underscores:

:table__column         # table.column
:column___alias        # column AS alias
:table__column___alias # table.column AS alias

It is only recommended to turn this on for backwards compatibility until such symbols have been converted to use newer Sequel APIs such as:

Sequel[:table][:column]            # table.column
Sequel[:column].as(:alias)         # column AS alias
Sequel[:table][:column].as(:alias) # table.column AS alias

Sequel::Database instances do their own caching of literalized symbols, and changing this setting does not affect those caches. It is recommended that if you want to change this setting, you do so directly after requiring Sequel, before creating any Sequel::Database instances.

Disabling symbol splitting will also disable the handling of double underscores in virtual row methods, causing such methods to yield regular identifers instead of qualified identifiers:

# Sequel.split_symbols = true
Sequel.expr{table__column}  # table.column
Sequel.expr{table[:column]} # table.column

# Sequel.split_symbols = false
Sequel.expr{table__column}  # table__column
Sequel.expr{table[:column]} # table.column
[show source]
    # File lib/sequel/core.rb
267 def split_symbols=(v)
268   Sequel.synchronize{SPLIT_SYMBOL_CACHE.clear}
269   @split_symbols = v
270 end

Whether Sequel currently splits symbols into qualified/aliased identifiers.

[show source]
    # File lib/sequel/core.rb
273 def split_symbols?
274   @split_symbols
275 end

A timer object that can be passed to Sequel.elapsed_seconds_since to return the number of seconds elapsed.

[show source]
    # File lib/sequel/core.rb
322 def start_timer
323   Process.clock_gettime(Process::CLOCK_MONOTONIC)
324 end

Converts the given string into a Date object.

Sequel.string_to_date('2010-09-10') # Date.civil(2010, 09, 10)
[show source]
    # File lib/sequel/core.rb
280 def string_to_date(string)
281   Date.parse(string, Sequel.convert_two_digit_years)
282 rescue => e
283   raise convert_exception_class(e, InvalidValue)
284 end

Converts the given string into a Time or DateTime object, depending on the value of Sequel.datetime_class.

Sequel.string_to_datetime('2010-09-10 10:20:30') # Time.local(2010, 09, 10, 10, 20, 30)
[show source]
    # File lib/sequel/core.rb
290 def string_to_datetime(string)
291   if datetime_class == DateTime
292     DateTime.parse(string, convert_two_digit_years)
293   else
294     datetime_class.parse(string)
295   end
296 rescue => e
297   raise convert_exception_class(e, InvalidValue)
298 end

Converts the given string into a Sequel::SQLTime object.

v = Sequel.string_to_time('10:20:30') # Sequel::SQLTime.parse('10:20:30')
DB.literal(v) # => '10:20:30'
[show source]
    # File lib/sequel/core.rb
304 def string_to_time(string)
305   SQLTime.parse(string)
306 rescue => e
307   raise convert_exception_class(e, InvalidValue)
308 end

Unless in single threaded mode, protects access to any mutable global data structure in Sequel. Uses a non-reentrant mutex, so calling code should be careful. In general, this should only be used around the minimal possible code such as Hash#[], Hash#[]=, Hash#delete, Array#<<, and Array#delete.

[show source]
    # File lib/sequel/core.rb
315 def synchronize(&block)
316   @single_threaded ? yield : @data_mutex.synchronize(&block)
317 end

If a mutex is given, synchronize access using it. If nil is given, just yield to the block. This is designed for cases where a mutex may or may not be provided.

[show source]
    # File lib/sequel/core.rb
182 def synchronize_with(mutex)
183   if mutex
184     mutex.synchronize{yield}
185   else
186     yield
187   end
188 end
transaction(dbs, opts=OPTS, &block)

Uses a transaction on all given databases with the given options. This:

Sequel.transaction([DB1, DB2, DB3]){}

is equivalent to:

DB1.transaction do
  DB2.transaction do
    DB3.transaction do

except that if Sequel::Rollback is raised by the block, the transaction is rolled back on all databases instead of just the last one.

Note that this method cannot guarantee that all databases will commit or rollback. For example, if DB3 commits but attempting to commit on DB2 fails (maybe because foreign key checks are deferred), there is no way to uncommit the changes on DB3. For that kind of support, you need to have two-phase commit/prepared transactions (which Sequel supports on some databases).

[show source]
    # File lib/sequel/core.rb
361 def transaction(dbs, opts=OPTS, &block)
362   unless opts[:rollback]
363     rescue_rollback = true
364     opts = Hash[opts].merge!(:rollback=>:reraise)
365   end
366   pr = dbs.reverse.inject(block){|bl, db| proc{db.transaction(opts, &bl)}}
367   if rescue_rollback
368     begin
370     rescue Sequel::Rollback
371       nil
372     end
373   else
375   end
376 end

Convert the given object into an object of Sequel.datetime_class in the application_timezone. Used when typecasting values when assigning them to model datetime attributes.

[show source]
    # File lib/sequel/timezones.rb
118 def typecast_to_application_timestamp(v)
119   convert_timestamp(v, Sequel.typecast_timezone)
120 end

If the supplied block takes a single argument, yield an SQL::VirtualRow instance to the block argument. Otherwise, evaluate the block in the context of a SQL::VirtualRow instance.

Sequel.virtual_row{a} #
Sequel.virtual_row{|o| o.a} #
[show source]
    # File lib/sequel/core.rb
385 def virtual_row(&block)
386   vr = VIRTUAL_ROW
387   case block.arity
388   when -1, 0
389     vr.instance_exec(&block)
390   else
392   end  
393 end