# module Base64

##
Overview

The `Base64` module provides for the encoding (`#encode`, `#strict_encode`, `#urlsafe_encode`) and decoding (`#decode`) of binary data using a base64 representation.

###
Example

A simple encoding and decoding.

    require "base64"

    enc = Base64.encode("Send reinforcements") # => "U2VuZCByZWluZm9yY2VtZW50cw==\n"
    plain = Base64.decode_string(enc)          # => "Send reinforcements"

The purpose of using base64 to encode data is that it translates any binary data into purely printable characters.

##
Extended Modules

- Base64

##
Defined in:

base64.cr

##
Instance Method Summary

- #decode(data, io : IO)

  Writes the base64-decoded version of data to io.

- #decode(data) : Bytes

  Returns the base64-decoded version of data as a `Bytes`.

- #decode_string(data) : String

  Returns the base64-decoded version of data as a string.

- #encode(data, io : IO)

  Writes the base64-encoded version of data to io.

- #encode(data) : String

  Returns the base64-encoded version of data.

- #strict_encode(data, io : IO)

  Writes the base64-encoded version of data with no newlines to io.

- #strict_encode(data) : String

  Returns the base64-encoded version of data with no newlines.

- #urlsafe_encode(data, io : IO)

  Writes the base64-encoded version of data using a urlsafe alphabet to io.

- #urlsafe_encode(data, padding = true) : String

  Returns the base64-encoded version of data using a urlsafe alphabet.

##
Instance Method Detail

def decode(data, io : IO) #

Writes the base64-decoded version of data to io. This will decode either the normal or urlsafe alphabets.

def decode(data) : Bytes #

Returns the base64-decoded version of data as a `Bytes`. This will decode either the normal or urlsafe alphabets.

def decode_string(data) : String #

Returns the base64-decoded version of data as a string. This will decode either the normal or urlsafe alphabets.

def encode(data, io : IO) #

Writes the base64-encoded version of data to io. This method complies with RFC 2045. Line feeds are added to every 60 encoded characters.

    Base64.encode("Now is the time for all good coders\nto learn Crystal", STDOUT)

def encode(data) : String #

Returns the base64-encoded version of data. This method complies with RFC 2045. Line feeds are added to every 60 encoded characters.

    puts Base64.encode("Now is the time for all good coders\nto learn Crystal")

Generates:

    Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g
    Q3J5c3RhbA==

def strict_encode(data, io : IO) #

Writes the base64-encoded version of data with no newlines to io. This method complies with RFC 4648.

    Base64.strict_encode("Now is the time for all good coders\nto learn Crystal", STDOUT)

def strict_encode(data) : String #

Returns the base64-encoded version of data with no newlines. This method complies with RFC 4648.

    puts Base64.strict_encode("Now is the time for all good coders\nto learn Crystal")

Generates:

    Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4gQ3J5c3RhbA==

def urlsafe_encode(data, io : IO) #

Writes the base64-encoded version of data using a urlsafe alphabet to io. This method complies with "Base 64 Encoding with URL and Filename Safe Alphabet" in RFC 4648.

The alphabet uses `'-'` instead of `'+'` and `'_'` instead of `'/'`.

def urlsafe_encode(data, padding = true) : String #

Returns the base64-encoded version of data using a urlsafe alphabet. This method complies with "Base 64 Encoding with URL and Filename Safe Alphabet" in RFC 4648.

The alphabet uses `'-'` instead of `'+'` and `'_'` instead of `'/'`.

The padding parameter defaults to `true`. When `false`, enough `=` characters are not added to make the output divisible by 4.