Open3 grants you access to stdin, stdout, stderr and a thread to wait for the child process when running another program. You can specify various attributes, redirections, current directory, etc., of the program in the same way as for Process.spawn.
Open3.popen3 : pipes for stdin, stdout, stderr
Open3.popen2 : pipes for stdin, stdout
Open3.popen2e : pipes for stdin, merged stdout and stderr
Open3.capture3 : give a string for stdin; get strings for stdout, stderr
Open3.capture2 : give a string for stdin; get a string for stdout
Open3.capture2e : give a string for stdin; get a string for merged stdout and stderr
Open3.pipeline_rw : pipes for first stdin and last stdout of a pipeline
Open3.pipeline_r : pipe for last stdout of a pipeline
Open3.pipeline_w : pipe for first stdin of a pipeline
Open3.pipeline_start : run a pipeline without waiting
Open3.pipeline : run a pipeline and wait for its completion
The Singleton module implements the Singleton pattern.
To use Singleton, include the module in your class.
class Klass include Singleton # ... end
This ensures that only one instance of Klass can be created.
a,b = Klass.instance, Klass.instance a == b # => true Klass.new # => NoMethodError - new is private ...
The instance is created at upon the first call of Klass.instance().
class OtherKlass include Singleton # ... end ObjectSpace.each_object(OtherKlass){} # => 0 OtherKlass.instance ObjectSpace.each_object(OtherKlass){} # => 1
This behavior is preserved under inheritance and cloning.
This above is achieved by:
Making Klass.new and Klass.allocate private.
Overriding Klass.inherited(sub_klass) and Klass.clone() to ensure that the Singleton properties are kept when inherited and cloned.
Providing the Klass.instance() method that returns the same object each time it is called.
Overriding Klass._load(str) to call Klass.instance().
Overriding Klass#clone and Klass#dup to raise TypeErrors to prevent cloning or duping.
Singleton and Marshal By default Singleton’s _dump(depth) returns the empty string. Marshalling by default will strip state information, e.g. instance variables from the instance. Classes using Singleton can provide custom _load(str) and _dump(depth) methods to retain some of the previous state of the instance.
require 'singleton' class Example include Singleton attr_accessor :keep, :strip def _dump(depth) # this strips the @strip information from the instance Marshal.dump(@keep, depth) end def self._load(str) instance.keep = Marshal.load(str) instance end end a = Example.instance a.keep = "keep this" a.strip = "get rid of this" stored_state = Marshal.dump(a) a.keep = nil a.strip = nil b = Marshal.load(stored_state) p a == b # => true p a.keep # => "keep this" p a.strip # => nil
Timeout long-running blocks
require 'timeout' status = Timeout::timeout(5) { # Something that should be interrupted if it takes more than 5 seconds... }
Timeout provides a way to auto-terminate a potentially long-running operation if it hasn’t finished in a fixed amount of time.
Previous versions didn’t use a module for namespacing, however timeout is provided for backwards compatibility. You should prefer Timeout.timeout instead.
© 2000 Network Applied Communication Laboratory, Inc.
© 2000 Information-technology Promotion Agency, Japan
This is not an existing class, but documentation of the interface that Scheduler object should comply in order to be used as Fiber.scheduler and handle non-blocking fibers. See also the “Non-blocking fibers” section in Fiber class docs for explanations of some concepts.
Scheduler’s behavior and usage are expected to be as follows:
When the execution in the non-blocking Fiber reaches some blocking operation (like sleep, wait for a process, or a non-ready I/O), it calls some of the scheduler’s hook methods, listed below.
Scheduler somehow registers what the current fiber is waited for, and yields control to other fibers with Fiber.yield (so the fiber would be suspended while expecting its wait to end, and other fibers in the same thread can perform)
At the end of the current thread execution, the scheduler’s method close is called
The scheduler runs into a wait loop, checking all the blocked fibers (which it has registered on hook calls) and resuming them when the awaited resource is ready (I/O ready, sleep time passed).
A typical implementation would probably rely for this closing loop on a gem like EventMachine or Async.
This way concurrent execution will be achieved in a way that is transparent for every individual Fiber’s code.
Hook methods are:
(the list is expanded as Ruby developers make more methods having non-blocking calls)
When not specified otherwise, the hook implementations are mandatory: if they are not implemented, the methods trying to call hook will fail. To provide backward compatibility, in the future hooks will be optional (if they are not implemented, due to the scheduler being created for the older Ruby version, the code which needs this hook will not fail, and will just behave in a blocking fashion).
It is also strongly suggested that the scheduler implement the fiber method, which is delegated to by Fiber.schedule.
Sample toy implementation of the scheduler can be found in Ruby’s code, in test/fiber/scheduler.rb
A base class for objects representing a C union
The base exception for JSON errors.
This exception is raised if the nesting of parsed data structures is too deep.
This exception is raised if a generator or unparser error occurs.
This class is used as a return value from ObjectSpace::reachable_objects_from.
When ObjectSpace::reachable_objects_from returns an object with references to an internal object, an instance of this class is returned.
You can use the type method to check the type of the internal object.
Generic error, common for all classes under OpenSSL module
General error for openssl library configuration files. Including formatting, parsing errors, etc.
Error raised when an error occurs on the underlying communication protocol.
Raised when the provided IP address is an invalid address.
HTTP response class.
This class wraps together the response header and the response body (the entity requested).
It mixes in the HTTPHeader module, which provides access to response header values both via hash-like methods and via individual readers.
Note that each possible HTTP response code defines its own HTTPResponse subclass. All classes are defined under the Net module. Indentation indicates inheritance. For a list of the classes see Net::HTTP.
Correspondence HTTP code => class is stored in CODE_TO_OBJ constant:
Net::HTTPResponse::CODE_TO_OBJ['404'] #=> Net::HTTPNotFound