Returns true if obj is an instance of the given class. See also Object#kind_of?.
class A; end class B < A; end class C < B; end b = B.new b.instance_of? A #=> false b.instance_of? B #=> true b.instance_of? C #=> false
Returns true if obj responds to the given method. Private and protected methods are included in the search only if the optional second parameter evaluates to true.
If the method is not implemented, as Process.fork on Windows, File.lchmod on GNU/Linux, etc., false is returned.
If the method is not defined, respond_to_missing? method is called and the result is returned.
When the method name parameter is given as a string, the string is converted to a symbol.
Methods Exception#as_json and Exception.json_create may be used to serialize and deserialize a Exception object; see Marshal.
Method Exception#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/exception' x = Exception.new('Foo').as_json # => {"json_class"=>"Exception", "m"=>"Foo", "b"=>nil}
Method JSON.create deserializes such a hash, returning a Exception object:
Exception.json_create(x) # => #<Exception: Foo>
Returns a JSON string representing self:
require 'json/add/exception' puts Exception.new('Foo').to_json
Output:
{"json_class":"Exception","m":"Foo","b":null}
Returns a new Time object with the same value as self; if self is a Julian date, derives its Gregorian date for conversion to the Time object:
Date.new(2001, 2, 3).to_time # => 2001-02-03 00:00:00 -0600 Date.new(2001, 2, 3, Date::JULIAN).to_time # => 2001-02-16 00:00:00 -0600
Returns a DateTime whose value is the same as self:
Date.new(2001, 2, 3).to_datetime # => #<DateTime: 2001-02-03T00:00:00+00:00>
See as_json.
Methods Date#as_json and Date.json_create may be used to serialize and deserialize a Date object; see Marshal.
Method Date#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/date' x = Date.today.as_json # => {"json_class"=>"Date", "y"=>2023, "m"=>11, "d"=>21, "sg"=>2299161.0}
Method JSON.create deserializes such a hash, returning a Date object:
Date.json_create(x) # => #<Date: 2023-11-21 ((2460270j,0s,0n),+0s,2299161j)>
Returns a JSON string representing self:
require 'json/add/date' puts Date.today.to_json
Output:
{"json_class":"Date","y":2023,"m":11,"d":21,"sg":2299161.0}
Returns a Time object which denotes self.
Returns self.
Methods DateTime#as_json and DateTime.json_create may be used to serialize and deserialize a DateTime object; see Marshal.
Method DateTime#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/datetime' x = DateTime.now.as_json # => {"json_class"=>"DateTime", "y"=>2023, "m"=>11, "d"=>21, "sg"=>2299161.0}
Method JSON.create deserializes such a hash, returning a DateTime object:
DateTime.json_create(x) # BUG? Raises Date::Error "invalid date"
Returns a JSON string representing self:
require 'json/add/datetime' puts DateTime.now.to_json
Output:
{"json_class":"DateTime","y":2023,"m":11,"d":21,"sg":2299161.0}
Returns self.
Returns a DateTime object which denotes self.
See as_json.
Methods Time#as_json and Time.json_create may be used to serialize and deserialize a Time object; see Marshal.
Method Time#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/time' x = Time.now.as_json # => {"json_class"=>"Time", "s"=>1700931656, "n"=>472846644}
Method JSON.create deserializes such a hash, returning a Time object:
Time.json_create(x) # => 2023-11-25 11:00:56.472846644 -0600
Returns a JSON string representing self:
require 'json/add/time' puts Time.now.to_json
Output:
{"json_class":"Time","s":1700931678,"n":980650786}
Return the number of seconds the specified time zone differs from UTC.
Numeric time zones that include minutes, such as -10:00 or +1330 will work, as will simpler hour-only time zones like -10 or +13.
Textual time zones listed in ZoneOffset are also supported.
If the time zone does not match any of the above, zone_offset will check if the local time zone (both with and without potential Daylight Saving Time changes being in effect) matches zone. Specifying a value for year will change the year used to find the local time zone.
If zone_offset is unable to determine the offset, nil will be returned.
require 'time' Time.zone_offset("EST") #=> -18000
You must require ‘time’ to use this method.
Waits until IO is priority and returns a truthy value or a falsy value when times out. Priority data is sent and received using the Socket::MSG_OOB flag and is typically limited to streams.
You must require ‘io/wait’ to use this method.
Attempts to convert object into an IO object via method to_io; returns the new IO object if successful, or nil otherwise:
IO.try_convert(STDOUT) # => #<IO:<STDOUT>> IO.try_convert(ARGF) # => #<IO:<STDIN>> IO.try_convert('STDOUT') # => nil
Returns self.
Reads at most maxlen bytes from ios using the read(2) system call after O_NONBLOCK is set for the underlying file descriptor.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
read_nonblock just calls the read(2) system call. It causes all errors the read(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The caller should care such errors.
If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying read_nonblock.
read_nonblock causes EOFError on EOF.
On some platforms, such as Windows, non-blocking mode is not supported on IO objects other than sockets. In such cases, Errno::EBADF will be raised.
If the read byte buffer is not empty, read_nonblock reads from the buffer like readpartial. In this case, the read(2) system call is not called.
When read_nonblock raises an exception kind of IO::WaitReadable, read_nonblock should not be called until io is readable for avoiding busy loop. This can be done as follows.
# emulates blocking read (readpartial). begin result = io.read_nonblock(maxlen) rescue IO::WaitReadable IO.select([io]) retry end
Although IO#read_nonblock doesn’t raise IO::WaitWritable. OpenSSL::Buffering#read_nonblock can raise IO::WaitWritable. If IO and SSL should be used polymorphically, IO::WaitWritable should be rescued too. See the document of OpenSSL::Buffering#read_nonblock for sample code.
Note that this method is identical to readpartial except the non-blocking flag is set.
By specifying a keyword argument exception to false, you can indicate that read_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead. At EOF, it will return nil instead of raising EOFError.