Package email :: Module base64mime
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Module base64mime

Base64 content transfer encoding per RFCs 2045-2047.

This module handles the content transfer encoding method defined in RFC 2045 to encode arbitrary 8-bit data using the three 8-bit bytes in four 7-bit characters encoding known as Base64.

It is used in the MIME standards for email to attach images, audio, and text using some 8-bit character sets to messages.

This module provides an interface to encode and decode both headers and bodies with Base64 encoding.

RFC 2045 defines a method for including character set information in an `encoded-word' in a header. This method is commonly used for 8-bit real names in To:, From:, Cc:, etc. fields, as well as Subject: lines.

This module does not do the line wrapping or end-of-line character conversion necessary for proper internationalized headers; it only does dumb encoding and decoding. To deal with the various line wrapping issues, use the email.Header module.

Functions [hide private]
 
base64_len(s)
Return the length of s when it is encoded with base64.
 
header_encode(header, charset='iso-8859-1', keep_eols=False, maxlinelen=76, eol='\n')
Encode a single header line with Base64 encoding in a given charset.
 
encode(s, binary=True, maxlinelen=76, eol='\n')
Encode a string with base64.
 
body_encode(s, binary=True, maxlinelen=76, eol='\n')
Encode a string with base64.
 
encodestring(s, binary=True, maxlinelen=76, eol='\n')
Encode a string with base64.
 
decode(s, convert_eols=None)
Decode a raw base64 string.
 
body_decode(s, convert_eols=None)
Decode a raw base64 string.
 
decodestring(s, convert_eols=None)
Decode a raw base64 string.
Variables [hide private]
  CRLF = '\r\n'
  NL = '\n'
  EMPTYSTRING = ''
  MISC_LEN = 7

Imports: re, b2a_base64, a2b_base64, fix_eols


Function Details [hide private]

header_encode(header, charset='iso-8859-1', keep_eols=False, maxlinelen=76, eol='\n')

 
Encode a single header line with Base64 encoding in a given charset.

Defined in RFC 2045, this Base64 encoding is identical to normal Base64
encoding, except that each line must be intelligently wrapped (respecting
the Base64 encoding), and subsequent lines must start with a space.

charset names the character set to use to encode the header.  It defaults
to iso-8859-1.

End-of-line characters (\r, \n, \r\n) will be automatically converted
to the canonical email line separator \r\n unless the keep_eols
parameter is True (the default is False).

Each line of the header will be terminated in the value of eol, which
defaults to "\n".  Set this to "\r\n" if you are using the result of
this function directly in email.

The resulting string will be in the form:

"=?charset?b?WW/5ciBtYXp66XLrIHf8eiBhIGhhbXBzdGHuciBBIFlv+XIgbWF6euly?=\n
  =?charset?b?6yB3/HogYSBoYW1wc3Rh7nIgQkMgWW/5ciBtYXp66XLrIHf8eiBhIGhh?="

with each line wrapped at, at most, maxlinelen characters (defaults to 76
characters).

encode(s, binary=True, maxlinelen=76, eol='\n')

 
Encode a string with base64.

    Each line will be wrapped at, at most, maxlinelen characters (defaults to
    76 characters).

    If binary is False, end-of-line characters will be converted to the
    canonical email end-of-line sequence \r\n.  Otherwise they will be left
    verbatim (this is the default).

    Each line of encoded text will end with eol, which defaults to "\n".  Set
    this to "
" if you will be using the result of this function directly
    in an email.
    

body_encode(s, binary=True, maxlinelen=76, eol='\n')

 
Encode a string with base64.

    Each line will be wrapped at, at most, maxlinelen characters (defaults to
    76 characters).

    If binary is False, end-of-line characters will be converted to the
    canonical email end-of-line sequence \r\n.  Otherwise they will be left
    verbatim (this is the default).

    Each line of encoded text will end with eol, which defaults to "\n".  Set
    this to "
" if you will be using the result of this function directly
    in an email.
    

encodestring(s, binary=True, maxlinelen=76, eol='\n')

 
Encode a string with base64.

    Each line will be wrapped at, at most, maxlinelen characters (defaults to
    76 characters).

    If binary is False, end-of-line characters will be converted to the
    canonical email end-of-line sequence \r\n.  Otherwise they will be left
    verbatim (this is the default).

    Each line of encoded text will end with eol, which defaults to "\n".  Set
    this to "
" if you will be using the result of this function directly
    in an email.
    

decode(s, convert_eols=None)

 

Decode a raw base64 string.

If convert_eols is set to a string value, all canonical email linefeeds, e.g. "\r\n", in the decoded text will be converted to the value of convert_eols. os.linesep is a good choice for convert_eols if you are decoding a text attachment.

This function does not parse a full MIME header value encoded with base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high level email.Header class for that functionality.

body_decode(s, convert_eols=None)

 

Decode a raw base64 string.

If convert_eols is set to a string value, all canonical email linefeeds, e.g. "\r\n", in the decoded text will be converted to the value of convert_eols. os.linesep is a good choice for convert_eols if you are decoding a text attachment.

This function does not parse a full MIME header value encoded with base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high level email.Header class for that functionality.

decodestring(s, convert_eols=None)

 

Decode a raw base64 string.

If convert_eols is set to a string value, all canonical email linefeeds, e.g. "\r\n", in the decoded text will be converted to the value of convert_eols. os.linesep is a good choice for convert_eols if you are decoding a text attachment.

This function does not parse a full MIME header value encoded with base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high level email.Header class for that functionality.