View Source base64 (stdlib v6.0)
Provides base64 encode and decode, see RFC 2045.
Provides base64 encode and decode, see RFC 2045.
Summary
Types
Base 64 Encoding alphabet, see RFC 4648.
Base 64 encoded binary.
Base 64 encoded string.
Arbitrary sequences of octets.
Customises the behaviour of the encode and decode functions. Default value if
omitted entirely or partially is #{mode => standard, padding => true}.
Functions
Equivalent to mime_decode_to_string/1
Equivalent to mime_decode_to_string/2
Equivalent to mime_decode_to_string/1
Equivalent to mime_decode_to_string/2
Equivalent to encode_to_string/1
Equivalent to encode_to_string/2
Encodes a plain ASCII string into base64 using the standard alphabet according to RFC 4648 Section 4. The result is 33% larger than the data.
Encodes a plain ASCII string into base64 using the alphabet indicated by the
mode option. The result is 33% larger than the data.
Equivalent to mime_decode_to_string/1
Equivalent to mime_decode_to_string/2
Decodes a base64 string encoded using the standard alphabet according to RFC 4648 Section 4 to plain ASCII.
Decodes a base64 string encoded using the alphabet indicated by the mode
option to plain ASCII.
Types
-type base64_alphabet() :: $A..$Z | $a..$z | $0..$9 | $+ | $/ | $- | $_ | $=.
Base 64 Encoding alphabet, see RFC 4648.
-type base64_binary() :: binary().
Base 64 encoded binary.
-type base64_mode() :: standard | urlsafe.
Selector for the Base 64 Encoding alphabet used for encoding and decoding. See RFC 4648 Sections 4 and 5.
-type base64_string() :: [base64_alphabet()].
Base 64 encoded string.
-type byte_string() :: [byte()].
Arbitrary sequences of octets.
-type options() :: #{padding => boolean(), mode => base64_mode()}.
Customises the behaviour of the encode and decode functions. Default value if
omitted entirely or partially is #{mode => standard, padding => true}.
Functions
-spec decode(Base64) -> Data when Base64 :: base64_string() | base64_binary(), Data :: binary().
Equivalent to mime_decode_to_string/1
-spec decode(Base64, Options) -> Data when Base64 :: base64_string() | base64_binary(), Options :: options(), Data :: binary().
Equivalent to mime_decode_to_string/2
-spec decode_to_string(Base64) -> DataString when Base64 :: base64_string() | base64_binary(), DataString :: byte_string().
Equivalent to mime_decode_to_string/1
-spec decode_to_string(Base64, Options) -> DataString when Base64 :: base64_string() | base64_binary(), Options :: options(), DataString :: byte_string().
Equivalent to mime_decode_to_string/2
-spec encode(Data) -> Base64 when Data :: byte_string() | binary(), Base64 :: base64_binary().
Equivalent to encode_to_string/1
-spec encode(Data, Options) -> Base64 when Data :: byte_string() | binary(), Options :: options(), Base64 :: base64_binary().
Equivalent to encode_to_string/2
-spec encode_to_string(Data) -> Base64String when Data :: byte_string() | binary(), Base64String :: base64_string().
Encodes a plain ASCII string into base64 using the standard alphabet according to RFC 4648 Section 4. The result is 33% larger than the data.
Always appends correct number of = padding characters to the encoded string.
-spec encode_to_string(Data, Options) -> Base64String when Data :: byte_string() | binary(), Options :: options(), Base64String :: base64_string().
Encodes a plain ASCII string into base64 using the alphabet indicated by the
mode option. The result is 33% larger than the data.
The mode option can be one of the following:
standard- Default. Encode the given string using the standard base64 alphabet according to RFC 4648 Section 4.urlsafe- Encode the given string using the alternative "URL and Filename safe" base64 alphabet according to RFC 4648 Section 5.
The padding option can be one of the following:
true- Default. Appends correct number of=padding characters to the encoded string.false- Skips appending=padding characters to the encoded string.
-spec mime_decode(Base64) -> Data when Base64 :: base64_string() | base64_binary(), Data :: binary().
Equivalent to mime_decode_to_string/1
-spec mime_decode(Base64, Options) -> Data when Base64 :: base64_string() | base64_binary(), Options :: options(), Data :: binary().
Equivalent to mime_decode_to_string/2
-spec mime_decode_to_string(Base64) -> DataString when Base64 :: base64_string() | base64_binary(), DataString :: byte_string().
Decodes a base64 string encoded using the standard alphabet according to RFC 4648 Section 4 to plain ASCII.
mime_decode/1 and
mime_decode_to_string/1 strip away illegal
characters, while decode/1 and
decode_to_string/1 only strip away whitespace
characters.
Checks the correct number of = padding characters at the end of the encoded
string.
-spec mime_decode_to_string(Base64, Options) -> DataString when Base64 :: base64_string() | base64_binary(), Options :: options(), DataString :: byte_string().
Decodes a base64 string encoded using the alphabet indicated by the mode
option to plain ASCII.
mime_decode/2 and
mime_decode_to_string/2 strip away illegal
characters, while decode/2 and
decode_to_string/2 only strip away whitespace
characters.
The mode option can be one of the following:
standard- Default. Decode the given string using the standard base64 alphabet according to RFC 4648 Section 4, that is"+"and"/"are representing bytes62and63respectively, while"-"and"_"are illegal characters.urlsafe- Decode the given string using the alternative "URL and Filename safe" base64 alphabet according to RFC 4648 Section 5, that is"-"and"_"are representing bytes62and63respectively, while"+"and"/"are illegal characters.
The padding option can be one of the following:
true- Default. Checks the correct number of=padding characters at the end of the encoded string.false- Accepts an encoded string with missing=padding characters at the end.