Encode a ShortText value in Base64url with padding.
See: RFC-4648 section 5
Examples:
encodeBase64 "<<?>>""PDw_Pj4="
:: a typeCtrl KGHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05
Modulebase64-1.0Haskell2010
This module contains ShortText-valued combinators implementing the RFC 4648 specification for the Base64url encoding format. This includes strictly padded/unpadded and lenient decoding variants, and external + internal validations for canonicity.
Encode a ShortText value in Base64url with padding.
See: RFC-4648 section 5
encodeBase64 "<<?>>""PDw_Pj4="
Encode a ShortText value in Base64url without padding.
See: RFC-4648 section 3.2
encodeBase64Unpadded "<<?>>""PDw_Pj4"
Decode an arbitrarily padded Base64url-encoded ShortText value.
For typed values: - If a padded value is required, use decodeBase64Padded - If an unpadded value is required, use decodeBase64Unpadded
See: RFC-4648 section 4
decodeBase64 $ assertBase64 @'UrlPadded "PDw_Pj4=""<<?>>"
decodeBase64 $ assertBase64 @'UrlUnpadded "PDw_Pj4""<<?>>"
Decode an untyped padded Base64url-encoded ShortText 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 encodings are optionally padded.
For a decoder that fails on unpadded input, use decodeBase64Unpadded.
Note: This function makes sure that decoding is total by deferring to
T.decodeUtf8. This will always round trip for any valid Base64-encoded
text value, but it may not round trip for bad inputs. The onus is on the
caller to make sure inputs are valid. If unsure, defer to decodeBase64With
and pass in a custom decode function.
See: RFC-4648 section 4
decodeBase64Untyped "PDw_Pj4="Right "<<?>>"
decodeBase64Untyped "PDw_Pj4"Right "<<?>>"
decodeBase64Untyped "PDw-Pg="Left "Base64-encoded bytestring has invalid padding"
decodeBase64Untyped "PDw-Pg"Right "<<>>"
decodeBase64UntypedWith :: (ShortByteString -> Either err ShortText)convert a bytestring to text (e.g. T.decodeUtf8')
-> ShortByteStringInput text to decode
-> Either (Base64Error err) ShortTextAttempt to decode an untyped ShortByteString value as Base64url, converting from
ByteString to ShortText according to some encoding function. In practice,
This is something like decodeUtf8', which may produce an error.
See: RFC-4648 section 4
decodeBase64With T.decodeUtf8'
:: ShortByteString -> Either (Base64Error UnicodeException) ShortText
Decode an unpadded Base64url encoded ShortText value.
See: RFC-4648 section 4
decodeBase64Unpadded $ assertBase64 @'UrlUnpadded "PDw_Pj4""<<?>>"
Decode an untyped, unpadded Base64url encoded ShortText value.
See: RFC-4648 section 4
decodeBase64UnpaddedUntyped "PDw_Pj4"Right "<<?>>"
decodeBase64UnpaddedUntyped "PDw_Pj4="Left "Base64-encoded bytestring has invalid padding"
decodeBase64UnpaddedUntypedWith :: (ShortByteString -> Either err ShortText)convert a bytestring to text (e.g. T.decodeUtf8')
-> ShortByteStringInput text to decode
-> Either (Base64Error err) ShortTextAttempt to decode an untyped, unpadded ShortByteString value as Base64url, converting from
ShortByteString to ShortText according to some encoding function. In practice,
This is something like decodeUtf8', which may produce an error.
See: RFC-4648 section 4
decodeBase64UnpaddedWith T.decodeUtf8'
:: ShortByteString -> Either (Base64Error UnicodeException) ShortText
Decode a padded Base64url encoded ShortText value
See: RFC-4648 section 4
decodeBase64Padded $ assertBase64 @'UrlPadded "PDw_Pj4=""<<?>>"
Decode an untyped, padded Base64url encoded ShortText value
See: RFC-4648 section 4
decodeBase64PaddedUntyped "PDw_Pj4="Right "<<?>>"
decodeBase64PaddedUntyped "PDw_Pj4"Left "Base64-encoded bytestring requires padding"
decodeBase64PaddedUntypedWith :: (ShortByteString -> Either err ShortText)convert a bytestring to text (e.g. T.decodeUtf8')
-> ShortByteStringInput text to decode
-> Either (Base64Error err) ShortTextAttempt to decode an untyped, padded ShortByteString value as Base64url, converting from
ByteString to ShortText according to some encoding function. In practice,
This is something like decodeUtf8', which may produce an error.
See: RFC-4648 section 4
decodeBase64With T.decodeUtf8'
:: ShortByteString -> Either (Base64Error UnicodeException) ShortText
Leniently decode an untyped, unpadded Base64url-encoded ShortText. 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.
decodeBase64Lenient "PDw_Pj4=""<<?>>"
decodeBase64Lenient "PDw_%%%$}Pj4""<<?>>"
Tell whether an untyped ShortText value is Base64url-encoded.
isBase64Url "PDw_Pj4="True
isBase64Url "PDw_Pj4"True
isBase64Url "PDw_Pj"False
Tell whether an untyped ShortText value is a valid Base64url format.
This will not tell you whether or not this is a correct Base64url representation, only that it conforms to the correct shape. To check whether it is a true Base64 encoded ShortText value, use isBase64Url.
isValidBase64Url "PDw_Pj4="True
isValidBase64Url "PDw_Pj"True
isValidBase64Url "%"False