base64

README

base64

base64 provides base64 encoding and decoding for Starlark, commonly used to represent binary data as ASCII text. It wraps Go's encoding/base64 and supports the standard and URL-safe alphabets, each with padded and raw (unpadded) variants. Capability profile: pure (no filesystem, network, process, or log side effects).

Functions

function	description
encode(data, encoding="standard") -> string	base64-encode a string or bytes, returning the encoded text
decode(data, encoding="standard") -> string	base64-decode a string or bytes, returning the decoded text

Encoding dialects

The optional encoding argument selects the alphabet and padding. An empty string is treated as "standard". Any other value raises unsupported encoding format: <value>.

encoding	meaning
"standard"	standard base64 with padding, RFC 4648 (default)
"standard_raw"	standard base64 without padding, RFC 4648 §3.2
"url"	URL- and filename-safe base64 with padding, RFC 4648
"url_raw"	URL- and filename-safe base64 without padding

Details & examples

encode

encode(data, encoding="standard") -> string

data is the input to encode and accepts a string or bytes; any other type raises base64.encode: for parameter data: got <type>, want string or bytes. The result is always a string. Errors on an unknown encoding value (see the dialects table).

load("base64", "encode")
print(encode("hello"))
print(encode("hello", encoding="standard_raw"))
print(encode("hello friend!", encoding="url"))
print(encode("hello friend!", encoding="url_raw"))
# Output:
# aGVsbG8=
# aGVsbG8
# aGVsbG8gZnJpZW5kIQ==
# aGVsbG8gZnJpZW5kIQ

decode

decode(data, encoding="standard") -> string

data is the base64-encoded input and accepts a string or bytes; any other type raises base64.decode: for parameter data: got <type>, want string or bytes. The result is the decoded text as a string. Errors on an unknown encoding value, and on malformed input for the chosen dialect (e.g. decoding the unpadded "aGVsbG8" with the default standard encoding raises illegal base64 data at input byte 4 — use encoding="standard_raw" for unpadded input).

load("base64", "decode")
print(decode("aGVsbG8="))
print(decode("aGVsbG8", encoding="standard_raw"))
print(decode("aGVsbG8gZnJpZW5kIQ==", encoding="url"))
print(decode("aGVsbG8gZnJpZW5kIQ", encoding="url_raw"))
# Output:
# hello
# hello
# hello friend!
# hello friend!

Notes / boundaries

• Engine: thin wrapper over Go's standard encoding/base64; behavior and error messages follow that package.
• The padded dialects (standard, url) require correct = padding on decode; the raw dialects (standard_raw, url_raw) require its absence. Mixing them raises an illegal base64 data error.
• Deterministic: the same input and dialect always yield the same output.
• decode returns a string; decoded bytes that are not valid UTF-8 are still returned as a Starlark string holding those bytes.

Documentation

Overview

Package base64 defines base64 encoding & decoding functions for Starlark.

Migrated from: https://github.com/qri-io/starlib/tree/master/encoding/base64

Index

• Constants
• Variables
• func LoadModule() (starlark.StringDict, error)

Constants

const ModuleName = "base64"

ModuleName defines the expected name for this Module when used in starlark's load() function, eg: load('base64', 'encode')

Variables

var Encodings = map[string]*gobase64.Encoding{

	"standard": gobase64.StdEncoding,

	"standard_raw": gobase64.RawStdEncoding,

	"url": gobase64.URLEncoding,

	"url_raw": gobase64.RawURLEncoding,
}

Encodings is a map of strings to encoding formats. It is used to select the encoding format for the base64 module. You can add your own encoding formats to this map.

Functions

func LoadModule

func LoadModule() (starlark.StringDict, error)

LoadModule loads the base64 module. It is concurrency-safe and idempotent.