Closes the write end of a duplex I/O stream (i.e., one that contains both a read and a write stream, such as a pipe). Will raise an IOError if the stream is not duplexed.
f = IO.popen("/bin/sh","r+") f.close_write f.print "nowhere"
produces:
prog.rb:3:in `write': not opened for writing (IOError) from prog.rb:3:in `print' from prog.rb:3
Calling this method on closed IO object is just ignored since Ruby 2.3.
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.
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.
Executes block for each key in the database, passing the key and the corresponding value as a parameter.
Returns a hash, that will be turned into a JSON object and represent this object.
Stores class name (OpenStruct) with this struct’s values v as a JSON string.
Yields all attributes (as symbols) along with the corresponding values or returns an enumerator if no block is given.
require "ostruct" data = OpenStruct.new("country" => "Australia", :capital => "Canberra") data.each_pair.to_a # => [[:country, "Australia"], [:capital, "Canberra"]]
Provides marshalling support for use by the Marshal library.
Provides marshalling support for use by the Marshal library.
Returns a hash, that will be turned into a JSON object and represent this object.
Stores class name (Range) with JSON array of arguments a which include first (integer), last (integer), and exclude_end? (boolean) as JSON string.
Deserializes JSON string by constructing new Regexp object with source s (Regexp or String) and options o serialized by to_json
Returns a hash, that will be turned into a JSON object and represent this object.
Returns a hash, that will be turned into a JSON object and represent this object.
Returns true if this class can be used to create an instance from a serialised JSON string. The class has to implement a class method json_create that expects a hash as first parameter. The hash should include the required data.
Return the path as a String.
to_path is implemented so Pathname objects are usable with File.open, etc.
Iterates over each key-value pair in the database.
If no block is given, returns an Enumerator.
Receives up to maxlen bytes from socket using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_ options. The first element of the results, mesg, is the data received. The second element, sender_addrinfo, contains protocol-specific address information of the sender.
When recvfrom(2) returns 0, Socket#recvfrom_nonblock returns an empty string as data. The meaning depends on the socket: EOF on TCP, empty packet on UDP, etc.
maxlen - the maximum number of bytes to receive from the socket
flags - zero or more of the MSG_ options
outbuf - destination String buffer
opts - keyword hash, supporting ‘exception: false`
# In one file, start this first require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.bind(sockaddr) socket.listen(5) client, client_addrinfo = socket.accept begin # emulate blocking recvfrom pair = client.recvfrom_nonblock(20) rescue IO::WaitReadable IO.select([client]) retry end data = pair[0].chomp puts "I only received 20 bytes '#{data}'" sleep 1 socket.close # In another file, start this second require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.connect(sockaddr) socket.puts "Watch this get cut short!" socket.close
Refer to Socket#recvfrom for the exceptions that may be thrown if the call to recvfrom_nonblock fails.
Socket#recvfrom_nonblock may raise any error corresponding to recvfrom(2) failure, including Errno::EWOULDBLOCK.
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 recvfrom_nonblock.
By specifying a keyword argument exception to false, you can indicate that recvfrom_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.
Accepts an incoming connection using accept(2) after O_NONBLOCK is set for the underlying file descriptor. It returns an array containing the accepted socket for the incoming connection, client_socket, and an Addrinfo, client_addrinfo.
# In one script, start this first require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.bind(sockaddr) socket.listen(5) begin # emulate blocking accept client_socket, client_addrinfo = socket.accept_nonblock rescue IO::WaitReadable, Errno::EINTR IO.select([socket]) retry end puts "The client said, '#{client_socket.readline.chomp}'" client_socket.puts "Hello from script one!" socket.close # In another script, start this second require 'socket' include Socket::Constants socket = Socket.new(AF_INET, SOCK_STREAM, 0) sockaddr = Socket.sockaddr_in(2200, 'localhost') socket.connect(sockaddr) socket.puts "Hello from script 2." puts "The server said, '#{socket.readline.chomp}'" socket.close
Refer to Socket#accept for the exceptions that may be thrown if the call to accept_nonblock fails.
Socket#accept_nonblock may raise any error corresponding to accept(2) failure, including Errno::EWOULDBLOCK.
If the exception is Errno::EWOULDBLOCK, Errno::EAGAIN, Errno::ECONNABORTED or Errno::EPROTO, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying accept_nonblock.
By specifying a keyword argument exception to false, you can indicate that accept_nonblock should not raise an IO::WaitReadable exception, but return the symbol :wait_readable instead.