base64
Copyright(c) 2019-2026 Emily Pillmore
LicenseBSD-style
MaintainerEmily Pillmore <emilypi@cohomolo.gy>
Stabilitystable
Portabilitynon-portable
Safe HaskellNone
LanguageHaskell2010

Data.ByteString.Short.Base64.URL

Description

This module contains ShortByteString-valued combinators for implementing the RFC 4648 specification of the Base64url encoding format. This includes strictly padded/unpadded and lenient decoding variants, as well as internal and external validation for canonicity.

Synopsis

Encoding

encodeBase64 :: ShortByteString -> Base64 'UrlPadded ShortText Source #

Encode a ShortByteString value as a Base64url Text value with padding.

See: RFC-4648 section 5

Examples:

>>> encodeBase64 "<<?>>"
"PDw_Pj4="

encodeBase64' :: ShortByteString -> Base64 'UrlPadded ShortByteString Source #

Encode a ShortByteString as a Base64url ShortByteString value with padding.

See: RFC-4648 section 5

Examples:

>>> encodeBase64' "<<?>>"
"PDw_Pj4="

encodeBase64Unpadded :: ShortByteString -> Base64 'UrlUnpadded ShortText Source #

Encode a ShortByteString value as Base64url Text without padding.

See: RFC-4648 section 3.2

Examples:

>>> encodeBase64Unpadded "<<?>>"
"PDw_Pj4"

encodeBase64Unpadded' :: ShortByteString -> Base64 'UrlUnpadded ShortByteString Source #

Encode a ShortByteString value as Base64url without padding.

See: RFC-4648 section 3.2

Examples:

>>> encodeBase64Unpadded' "<<?>>"
"PDw_Pj4"

Decoding

decodeBase64 :: forall (k :: Alphabet). UrlAlphabet k => Base64 k ShortByteString -> ShortByteString Source #

Decode a Base64url encoded ShortByteString value, either padded or unpadded. The correct decoding function is dispatched based on the existence of padding.

For typed values: - If a padded value is required, use decodeBase64Padded - If an unpadded value is required, use decodeBase64Unpadded

See: RFC-4648 section 4

Examples:

>>> decodeBase64 $ assertBase64 @'UrlPadded "PDw_Pj4="
"<<?>>"
>>> decodeBase64 $ assertBase64 @'UrlUnpadded "PDw_Pj4"
"<<?>>"

decodeBase64Untyped :: ShortByteString -> Either Text ShortByteString Source #

Decode an untyped Base64url encoded ByteString value. If its length is not a multiple of 4, then padding chars will be added to fill out the input to a multiple of 4 for safe decoding as Base64url-encoded values are optionally padded.

For a decoder that fails to decode untyped values of incorrect size: - If a padded value is required, use decodeBase64PaddedUntyped - If an unpadded value is required, use decodeBase64UnpaddedUntyped

See: RFC-4648 section 4

Examples:

>>> decodeBase64Untyped "PDw_Pj4="
Right "<<?>>"
>>> decodeBase64Untyped "PDw_Pj4"
Right "<<?>>"
>>> decodeBase64Untyped "PDw-Pg="
Left "Base64-encoded bytestring has invalid padding"
>>> decodeBase64Untyped "PDw-Pg"
Right "<<>>"

decodeBase64Unpadded :: Base64 'UrlUnpadded ShortByteString -> ShortByteString Source #

Decode an unpadded Base64url-encoded ShortByteString value.

See: RFC-4648 section 4

Examples:

>>> decodeBase64Unpadded $ assertBase64 @'UrlUnpadded "PDw_Pj4"
"<<?>>"

decodeBase64UnpaddedUntyped :: ShortByteString -> Either Text ShortByteString Source #

Decode an unpadded, untyped Base64url encoded ByteString value. If its length is not a multiple of 4, then padding chars will be added to fill out the input to a multiple of 4 for safe decoding as Base64url-encoded values are optionally padded.

In general, unless unpadded Base64url is explicitly required, it is safer to call decodeBase64.

See: RFC-4648 section 4

Examples:

>>> decodeBase64UnpaddedUntyped "PDw_Pj4"
Right "<<?>>"
>>> decodeBase64UnpaddedUntyped "PDw-Pg="
Left "Base64-encoded bytestring has invalid padding"
>>> decodeBase64UnpaddedUntyped "PDw-Pg"
Right "<<>>"

decodeBase64Padded :: Base64 'UrlPadded ShortByteString -> ShortByteString Source #

Decode a padded Base64url-encoded ShortByteString value.

See: RFC-4648 section 4

Examples:

>>> decodeBase64Padded $ assertBase64 @'UrlPadded "PDw_Pj4="
"<<?>>"

decodeBase64PaddedUntyped :: ShortByteString -> Either Text ShortByteString Source #

Decode a padded, untyped Base64url encoded ByteString value.

For a decoder that fails on unpadded input of incorrect size, use decodeBase64UnpaddedUntyped.

See: RFC-4648 section 4

Examples:

>>> decodeBase64PaddedUntyped "PDw_Pj4="
Right "<<?>>"
>>> decodeBase64PaddedUntyped "PDw_Pj4"
Left "Base64-encoded bytestring requires padding"

decodeBase64Lenient :: ShortByteString -> ShortByteString Source #

Leniently decode an unpadded, untyped Base64url-encoded ShortByteString. This function will not generate parse errors. If input data contains padding chars, then the input will be parsed up until the first pad character.

Note: This is not RFC 4648-compliant.

Examples:

>>> decodeBase64Lenient "PDw_Pj4="
"<<?>>"
>>> decodeBase64Lenient "PDw_%%%$}Pj4"
"<<?>>"

Parsing

parseBase64Padded :: ShortByteString -> Either Text (Base64 'UrlPadded ShortByteString) Source #

Parse a canonical, padded Base64url-encoded ShortByteString value.

Checks the URL-safe alphabet, length, padding, and unused padding bits. Returns the original encoded value wrapped in Base64, ready for decodeBase64Padded or decodeBase64. Errors match the strict ByteString decodeBase64PaddedUntyped decoder. The input is neither decoded nor normalized in the returned value.

Examples:

>>> parseBase64Padded "PDw_Pj4="
Right "PDw_Pj4="
>>> fmap decodeBase64Padded (parseBase64Padded "PDw_Pj4=")
Right "<<?>>"
>>> parseBase64Padded "PDw_Pj4"
Left "Base64-encoded bytestring requires padding"
>>> parseBase64Padded "ZE=="
Left "non-canonical encoding detected at offset: 1"

Since: 2.1

parseBase64Unpadded :: ShortByteString -> Either Text (Base64 'UrlUnpadded ShortByteString) Source #

Parse a canonical, unpadded Base64url-encoded ShortByteString value.

Checks the URL-safe alphabet, length, padding, and unused padding bits. Returns the original encoded value wrapped in Base64, ready for decodeBase64Unpadded or decodeBase64. Errors match the strict ByteString decodeBase64UnpaddedUntyped decoder. The input is neither decoded nor normalized in the returned value.

Examples:

>>> parseBase64Unpadded "PDw_Pj4"
Right "PDw_Pj4"
>>> fmap decodeBase64Unpadded (parseBase64Unpadded "PDw_Pj4")
Right "<<?>>"
>>> parseBase64Unpadded "PDw_Pj4="
Left "Base64-encoded bytestring has invalid padding"
>>> parseBase64Unpadded "ZE"
Left "non-canonical encoding detected at offset: 1"

Since: 2.1