class IO::Hexdump

• IO::Hexdump
• IO
• Reference
• Object

Overview

IO object that prints an hexadecimal dump of all transferred data.

Especially useful for debugging binary protocols on an IO, to understand better when and how data is sent or received.

By default IO::Hexdump won't print anything; you must specify which of #read, #write or both you want to print.

Example:

require "io/hexdump"
socket = IO::Memory.new("abc")
io = IO::Hexdump.new(socket, output: STDERR, read: true)

When data is read from io it will print something akin to the following on STDERR:

00000000  50 52 49 20 2a 20 48 54  54 50 2f 32 2e 30 0d 0a  PRI * HTTP/2.0..
00000010  0d 0a 53 4d 0d 0a 0d 0a                           ..SM....
00000000  00 00 00 04                                       ....
00000000  00                                                .
00000000  00 00 00 00                                       ....

Defined in:

Constructors

• .new(io : IO, output : IO = STDERR, read : Bool = false, write : Bool = false)

Instance Method Summary

• #close(*args, **options)
• #close(*args, **options, &)
• #closed?(*args, **options)
• #closed?(*args, **options, &)
• #flush(*args, **options)
• #flush(*args, **options, &)
• #peek(*args, **options)
• #peek(*args, **options, &)
• #pos(*args, **options)
• #pos(*args, **options, &)
• #pos=(arg)

  Sets the current position (in bytes) in this IO.

• #read(slice : Bytes) : Int32

  Reads at most slice.size bytes from this IO into slice.

• #read(*, buf : Bytes) : Int32

  DEPRECATED Use #read(slice : Bytes) instead

• #seek(*args, **options)
• #seek(*args, **options, &)
• #tty?(*args, **options)
• #tty?(*args, **options, &)
• #write(slice : Bytes) : Nil

  Writes the contents of slice into this IO.

• #write(*, buf : Bytes) : Nil

  DEPRECATED Use #write(slice : Bytes) instead

Constructor Detail

Instance Method Detail

File.write("testfile", "hello")

file = File.new("testfile")
file.pos = 3
file.gets_to_end # => "lo"

io = IO::Memory.new "hello"
slice = Bytes.new(4)
io.read(slice) # => 4
slice          # => Bytes[104, 101, 108, 108]
io.read(slice) # => 1
slice          # => Bytes[111, 101, 108, 108]
io.read(slice) # => 0

io = IO::Memory.new
slice = Bytes.new(4) { |i| ('a'.ord + i).to_u8 }
io.write(slice)
io.to_s # => "abcd"