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/Crystal 0.31

class IO::Hexdump

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:

io/hexdump.cr

Constructors

Instance Method Summary

Instance methods inherited from class IO

<self <<, close close, closed? closed?, each_byte(&block) : Nil
each_byte each_byte
, each_char(&block) : Nil
each_char each_char
, each_line(*args, **options, &block : String -> ) : Nil
each_line(*args, **options) each_line
, encoding : String encoding, flush flush, gets(delimiter : Char, limit : Int, chomp = false) : String?
gets(delimiter : Char, chomp = false) : String?
gets(chomp = true) : String?
gets(limit : Int, chomp = false) : String?
gets(delimiter : String, chomp = false) : String? gets
, gets_to_end : String gets_to_end, peek : Bytes? peek, pos pos, pos=(value) pos=, print(*objects : UNDERSCORE) : Nil
print(obj) : Nil print
, printf(format_string, *args) : Nil
printf(format_string, args : Array | Tuple) : Nil printf
, puts(*objects : UNDERSCORE) : Nil
puts : Nil
puts(obj) : Nil
puts(string : String) : Nil puts
, read(slice : Bytes) read, read_at(offset, bytesize, &block) read_at, read_byte : UInt8? read_byte, read_bytes(type, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) read_bytes, read_char : Char? read_char, read_fully(slice : Bytes) read_fully, read_fully?(slice : Bytes) read_fully?, read_line(*args, **options) : String read_line, read_string(bytesize : Int) : String read_string, read_utf8(slice : Bytes) read_utf8, read_utf8_byte read_utf8_byte, rewind rewind, seek(offset, whence : Seek = Seek::Set) seek, set_encoding(encoding : String, invalid : Symbol? = nil) set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tell tell, tty? : Bool tty?, write(slice : Bytes) : Nil write, write_byte(byte : UInt8) write_byte, write_bytes(object, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) write_bytes, write_utf8(slice : Bytes) write_utf8

Class methods inherited from class IO

copy(src, dst, limit : Int) : UInt64
copy(src, dst) : UInt64 copy
, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &block) pipe

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==
, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference)
same?(other : Nil) same?
, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

!=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===
, =~(other) =~, class class, dup dup, hash(hasher)
hash hash
, inspect(io : IO) : Nil
inspect : String inspect
, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
to_json to_json
, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json
, to_s : String
to_s(io : IO) : Nil to_s
, to_yaml(io : IO)
to_yaml to_yaml
, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as

Constructor methods inherited from class Object

from_json(string_or_io, root : String) : self
from_json(string_or_io) : self from_json
, from_yaml(string_or_io : String | IO) : self from_yaml

Constructor Detail

def self.new(io : IO, output : IO = STDERR, read = false, write = false)Source

Instance Method Detail

def closeSource

Description copied from class IO

Closes this IO.

IO defines this is a no-op method, but including types may override.

def closed?Source

Description copied from class IO

Returns true if this IO is closed.

IO defines returns false, but including types may override.

def flushSource

Description copied from class IO

Flushes buffered data, if any.

IO defines this is a no-op method, but including types may override.

def peekSource

Description copied from class IO

Peeks into this IO, if possible.

It returns:

  • nil if this IO isn't peekable
  • an empty slice if it is, but EOF was reached
  • a non-empty slice if some data can be peeked

The returned bytes are only valid data until a next call to any method that reads from this IO is invoked.

By default this method returns nil, but IO implementations that provide buffering or wrap other IOs should override this method.

def read(buf : Bytes)Source

Description copied from class IO

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

def tty?Source

Description copied from class IO

Returns true if this IO is associated with a terminal device (tty), false otherwise.

IO returns false, but including types may override.

STDIN.tty?          # => true
IO::Memory.new.tty? # => false

def write(buf : Bytes) : NilSource

Description copied from class IO

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"

© 2012–2019 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/0.31.1/IO/Hexdump.html