Closes the stream for reading if open for reading; returns nil. See Open and Closed Streams.
If the stream was opened by IO.popen and is also closed for writing, sets global variable $? (child exit status).
Example:
IO.popen('ruby', 'r+') do |pipe| puts pipe.closed? pipe.close_write puts pipe.closed? pipe.close_read puts $? puts pipe.closed? end
Output:
false false pid 14748 exit 0 true
Related: IO#close, IO#close_write, IO#closed?.
Closes the stream for writing if open for writing; returns nil. See Open and Closed Streams.
Flushes any buffered writes to the operating system before closing.
If the stream was opened by IO.popen and is also closed for reading, sets global variable $? (child exit status).
IO.popen('ruby', 'r+') do |pipe| puts pipe.closed? pipe.close_read puts pipe.closed? pipe.close_write puts $? puts pipe.closed? end
Output:
false false pid 15044 exit 0 true
Related: IO#close, IO#close_read, IO#closed?.
Returns the path associated with the IO, or nil if there is no path associated with the IO. It is not guaranteed that the path exists on the filesystem.
$stdin.path # => "<STDIN>" File.open("testfile") {|f| f.path} # => "testfile"
Returns the Encoding object that represents the encoding of the stream, or nil if the stream is in write mode and no encoding is specified.
See Encodings.
Returns the Encoding object that represents the encoding of the internal string, if conversion is specified, or nil otherwise.
See Encodings.
See Encodings.
Argument ext_enc, if given, must be an Encoding object or a String with the encoding name; it is assigned as the encoding for the stream.
Argument int_enc, if given, must be an Encoding object or a String with the encoding name; it is assigned as the encoding for the internal string.
Argument 'ext_enc:int_enc', if given, is a string containing two colon-separated encoding names; corresponding Encoding objects are assigned as the external and internal encodings for the stream.
If the external encoding of a string is binary/ASCII-8BIT, the internal encoding of the string is set to nil, since no transcoding is needed.
Optional keyword arguments enc_opts specify Encoding options.
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.
Writes the given string to ios using the write(2) system call after O_NONBLOCK is set for the underlying file descriptor.
It returns the number of bytes written.
write_nonblock just calls the write(2) system call. It causes all errors the write(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The result may also be smaller than string.length (partial write). The caller should care such errors and partial write.
If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying write_nonblock.
# Creates a pipe. r, w = IO.pipe # write_nonblock writes only 65536 bytes and return 65536. # (The pipe size is 65536 bytes on this environment.) s = "a" * 100000 p w.write_nonblock(s) #=> 65536 # write_nonblock cannot write a byte and raise EWOULDBLOCK (EAGAIN). p w.write_nonblock("b") # Resource temporarily unavailable (Errno::EAGAIN)
If the write buffer is not empty, it is flushed at first.
When write_nonblock raises an exception kind of IO::WaitWritable, write_nonblock should not be called until io is writable for avoiding busy loop. This can be done as follows.
begin result = io.write_nonblock(string) rescue IO::WaitWritable, Errno::EINTR IO.select(nil, [io]) retry end
Note that this doesn’t guarantee to write all data in string. The length written is reported as result and it should be checked later.
On some platforms such as Windows, write_nonblock is not supported according to the kind of the IO object. In such cases, write_nonblock raises Errno::EBADF.
By specifying a keyword argument exception to false, you can indicate that write_nonblock should not raise an IO::WaitWritable exception, but return the symbol :wait_writable instead.
Methods BigDecimal#as_json and BigDecimal.json_create may be used to serialize and deserialize a BigDecimal object; see Marshal.
Method BigDecimal#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/bigdecimal' x = BigDecimal(2).as_json # => {"json_class"=>"BigDecimal", "b"=>"27:0.2e1"} y = BigDecimal(2.0, 4).as_json # => {"json_class"=>"BigDecimal", "b"=>"36:0.2e1"} z = BigDecimal(Complex(2, 0)).as_json # => {"json_class"=>"BigDecimal", "b"=>"27:0.2e1"}
Method JSON.create deserializes such a hash, returning a BigDecimal object:
BigDecimal.json_create(x) # => 0.2e1 BigDecimal.json_create(y) # => 0.2e1 BigDecimal.json_create(z) # => 0.2e1
Returns a JSON string representing self:
require 'json/add/bigdecimal' puts BigDecimal(2).to_json puts BigDecimal(2.0, 4).to_json puts BigDecimal(Complex(2, 0)).to_json
Output:
{"json_class":"BigDecimal","b":"27:0.2e1"}
{"json_class":"BigDecimal","b":"36:0.2e1"}
{"json_class":"BigDecimal","b":"27:0.2e1"}
Methods OpenStruct#as_json and OpenStruct.json_create may be used to serialize and deserialize a OpenStruct object; see Marshal.
Method OpenStruct#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/ostruct' x = OpenStruct.new('name' => 'Rowdy', :age => nil).as_json # => {"json_class"=>"OpenStruct", "t"=>{:name=>'Rowdy', :age=>nil}}
Method JSON.create deserializes such a hash, returning a OpenStruct object:
OpenStruct.json_create(x) # => #<OpenStruct name='Rowdy', age=nil>
Returns a JSON string representing self:
require 'json/add/ostruct' puts OpenStruct.new('name' => 'Rowdy', :age => nil).to_json
Output:
{"json_class":"OpenStruct","t":{'name':'Rowdy',"age":null}}
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"]]
Methods Range#as_json and Range.json_create may be used to serialize and deserialize a Range object; see Marshal.
Method Range#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/range' x = (1..4).as_json # => {"json_class"=>"Range", "a"=>[1, 4, false]} y = (1...4).as_json # => {"json_class"=>"Range", "a"=>[1, 4, true]} z = ('a'..'d').as_json # => {"json_class"=>"Range", "a"=>["a", "d", false]}
Method JSON.create deserializes such a hash, returning a Range object:
Range.json_create(x) # => 1..4 Range.json_create(y) # => 1...4 Range.json_create(z) # => "a".."d"
Returns a JSON string representing self:
require 'json/add/range' puts (1..4).to_json puts (1...4).to_json puts ('a'..'d').to_json
Output:
{"json_class":"Range","a":[1,4,false]}
{"json_class":"Range","a":[1,4,true]}
{"json_class":"Range","a":["a","d",false]}
Methods Rational#as_json and Rational.json_create may be used to serialize and deserialize a Rational object; see Marshal.
Method Rational#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/rational' x = Rational(2, 3).as_json # => {"json_class"=>"Rational", "n"=>2, "d"=>3}
Method JSON.create deserializes such a hash, returning a Rational object:
Rational.json_create(x) # => (2/3)
Returns a JSON string representing self:
require 'json/add/rational' puts Rational(2, 3).to_json
Output:
{"json_class":"Rational","n":2,"d":3}
Methods Regexp#as_json and Regexp.json_create may be used to serialize and deserialize a Regexp object; see Marshal.
Method Regexp#as_json serializes self, returning a 2-element hash representing self:
require 'json/add/regexp' x = /foo/.as_json # => {"json_class"=>"Regexp", "o"=>0, "s"=>"foo"}
Method JSON.create deserializes such a hash, returning a Regexp object:
Regexp.json_create(x) # => /foo/
Returns a JSON string representing self:
require 'json/add/regexp' puts /foo/.to_json
Output:
{"json_class":"Regexp","o":0,"s":"foo"}
Returns a hash representing named captures of self (see Named Captures):
Each key is the name of a named capture.
Each value is an array of integer indexes for that named capture.
Examples:
/(?<foo>.)(?<bar>.)/.named_captures # => {"foo"=>[1], "bar"=>[2]} /(?<foo>.)(?<foo>.)/.named_captures # => {"foo"=>[1, 2]} /(.)(.)/.named_captures # => {}