Copyright | (c) 2019-2020 Emily Pillmore |
---|---|
License | BSD-style |
Maintainer | Emily Pillmore <emilypi@cohomolo.gy> |
Stability | stable |
Portability | non-portable |
Safe Haskell | Safe |
Language | Haskell2010 |
This module contains Text
-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
- encodeBase64 :: Text -> Text
- encodeBase64Unpadded :: Text -> Text
- decodeBase64 :: Text -> Either Text Text
- decodeBase64With :: (ByteString -> Either err Text) -> ByteString -> Either (Base64Error err) Text
- decodeBase64Unpadded :: Text -> Either Text Text
- decodeBase64UnpaddedWith :: (ByteString -> Either err Text) -> ByteString -> Either (Base64Error err) Text
- decodeBase64Padded :: Text -> Either Text Text
- decodeBase64PaddedWith :: (ByteString -> Either err Text) -> ByteString -> Either (Base64Error err) Text
- decodeBase64Lenient :: Text -> Text
- isBase64Url :: Text -> Bool
- isValidBase64Url :: Text -> Bool
Encoding
encodeBase64 :: Text -> Text Source #
Encode a Text
value in Base64url with padding.
See: RFC-4648 section 5
Examples:
>>>
encodeBase64 "<<?>>"
"PDw_Pj4="
encodeBase64Unpadded :: Text -> Text Source #
Encode a Text
value in Base64url without padding. Note that for Base64url,
padding is optional. If you call this function, you will simply be encoding
as Base64url and stripping padding chars from the output.
See: RFC-4648 section 3.2
Examples:
>>>
encodeBase64Unpadded "<<?>>"
"PDw_Pj4"
Decoding
decodeBase64 :: Text -> Either Text Text Source #
Decode a padded Base64url-encoded Text
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
decodeLatin1
. 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
Examples:
>>>
decodeBase64 "PDw_Pj4="
Right "<<?>>"
>>>
decodeBase64 "PDw_Pj4"
Right "<<?>>"
>>>
decodeBase64 "PDw-Pg="
Left "Base64-encoded bytestring has invalid padding"
>>>
decodeBase64 "PDw-Pg"
Right "<<>>"
:: (ByteString -> Either err Text) | convert a bytestring to text (e.g. |
-> ByteString | Input text to decode |
-> Either (Base64Error err) Text |
Attempt to decode a lazy ByteString
value as Base64url, converting from
ByteString
to Text
according to some encoding function. In practice,
This is something like decodeUtf8'
, which may produce an error.
See: RFC-4648 section 4
Examples:
decodeBase64With
decodeUtf8'
::ByteString
->Either
(Base64Error
UnicodeException
)Text
decodeBase64Unpadded :: Text -> Either Text Text Source #
Decode an unpadded Base64url encoded Text
value.
Note: This function makes sure that decoding is total by deferring to
decodeLatin1
. 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 decodeBase64WUnpaddedWith
and pass in a custom decode function.
See: RFC-4648 section 4
Examples:
>>>
decodeBase64Unpadded "PDw_Pj4"
Right "<<?>>"
>>>
decodeBase64Unpadded "PDw_Pj4="
Left "Base64-encoded bytestring has invalid padding"
decodeBase64UnpaddedWith Source #
:: (ByteString -> Either err Text) | convert a bytestring to text (e.g. |
-> ByteString | Input text to decode |
-> Either (Base64Error err) Text |
Attempt to decode an unpadded lazy ByteString
value as Base64url, converting from
ByteString
to Text
according to some encoding function. In practice,
This is something like decodeUtf8'
, which may produce an error.
See: RFC-4648 section 4
Examples:
decodeBase64UnpaddedWith
decodeUtf8'
::ByteString
->Either
(Base64Error
UnicodeException
)Text
decodeBase64Padded :: Text -> Either Text Text Source #
Decode an padded Base64url encoded Text
value
Note: This function makes sure that decoding is total by deferring to
decodeLatin1
. 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 decodeBase64PaddedWith
and pass in a custom decode function.
See: RFC-4648 section 4
Examples:
>>>
decodeBase64Padded "PDw_Pj4="
Right "<<?>>"
>>>
decodeBase64Padded "PDw_Pj4"
Left "Base64-encoded bytestring requires padding"
decodeBase64PaddedWith Source #
:: (ByteString -> Either err Text) | convert a bytestring to text (e.g. |
-> ByteString | Input text to decode |
-> Either (Base64Error err) Text |
Attempt to decode a padded lazy ByteString
value as Base64url, converting from
ByteString
to Text
according to some encoding function. In practice,
This is something like decodeUtf8'
, which may produce an error.
See: RFC-4648 section 4
Example:
decodeBase64PaddedWith
decodeUtf8'
::ByteString
->Either
(Base64Error
UnicodeException
)Text
decodeBase64Lenient :: Text -> Text Source #
Leniently decode an unpadded Base64url-encoded Text
. 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"
"<<?>>"
Validation
isBase64Url :: Text -> Bool Source #
Tell whether a Text
value is Base64url-encoded
Examples:
>>>
isBase64Url "PDw_Pj4="
True
>>>
isBase64Url "PDw_Pj4"
True
>>>
isBase64Url "PDw_Pj"
False
isValidBase64Url :: Text -> Bool Source #
Tell whether a Text
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 Text
value, use isBase64Url
.
Examples:
>>>
isValidBase64Url "PDw_Pj4="
True
>>>
isValidBase64Url "PDw_Pj"
True
>>>
isValidBase64Url "%"
False