class IO::Hexdump
inherits IO
¶
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 ....
Class methods¶
Methods¶
#pos=(arg)
¶
(arg)
Sets the current position (in bytes) in this IO.
The IO class raises on this method, but some subclasses, notable
IO::FileDescriptor and IO::Memory implement it.
File.write("testfile", "hello")
file = File.new("testfile")
file.pos = 3
file.gets_to_end # => "lo"
#read(buf : Bytes)
¶
(buf : Bytes)
Reads at most slice.size bytes from this IO into slice.
Returns the number of bytes read, which is 0 if and only if there is no
more data to read (so checking for 0 is the way to detect end of file).
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
#write(buf : Bytes) : Nil
¶
(buf : Bytes) : Nil
Writes the contents of slice into this IO.
io = IO::Memory.new
slice = Bytes.new(4) { |i| ('a'.ord + i).to_u8 }
io.write(slice)
io.to_s # => "abcd"