Mercurial > repos > guerler > springsuite

comparison planemo/lib/python3.7/site-packages/future/backports/email/base64mime.py @ 0:d30785e31577 draft

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
"planemo upload commit 6eee67778febed82ddd413c3ca40b3183a3898f1"
author guerler
date Fri, 31 Jul 2020 00:18:57 -0400
parents
children
comparison
equal deleted inserted replaced
-1:000000000000 0:d30785e31577
1 # Copyright (C) 2002-2007 Python Software Foundation
2 # Author: Ben Gertzfield
3 # Contact: email-sig@python.org
4
5 """Base64 content transfer encoding per RFCs 2045-2047.
6
7 This module handles the content transfer encoding method defined in RFC 2045
8 to encode arbitrary 8-bit data using the three 8-bit bytes in four 7-bit
9 characters encoding known as Base64.
10
11 It is used in the MIME standards for email to attach images, audio, and text
12 using some 8-bit character sets to messages.
13
14 This module provides an interface to encode and decode both headers and bodies
15 with Base64 encoding.
16
17 RFC 2045 defines a method for including character set information in an
18 `encoded-word' in a header. This method is commonly used for 8-bit real names
19 in To:, From:, Cc:, etc. fields, as well as Subject: lines.
20
21 This module does not do the line wrapping or end-of-line character conversion
22 necessary for proper internationalized headers; it only does dumb encoding and
23 decoding. To deal with the various line wrapping issues, use the email.header
24 module.
25 """
26 from __future__ import unicode_literals
27 from __future__ import division
28 from __future__ import absolute_import
29 from future.builtins import range
30 from future.builtins import bytes
31
32 __all__ = [
33 'body_decode',
34 'body_encode',
35 'decode',
36 'decodestring',
37 'header_encode',
38 'header_length',
39 ]
40
41
42 from base64 import b64encode
43 from binascii import b2a_base64, a2b_base64
44
45 CRLF = '\r\n'
46 NL = '\n'
47 EMPTYSTRING = ''
48
49 # See also Charset.py
50 MISC_LEN = 7
51
52
53 # Helpers
54 def header_length(bytearray):
55 """Return the length of s when it is encoded with base64."""
56 groups_of_3, leftover = divmod(len(bytearray), 3)
57 # 4 bytes out for each 3 bytes (or nonzero fraction thereof) in.
58 n = groups_of_3 * 4
59 if leftover:
60 n += 4
61 return n
62
63
64 def header_encode(header_bytes, charset='iso-8859-1'):
65 """Encode a single header line with Base64 encoding in a given charset.
66
67 charset names the character set to use to encode the header. It defaults
68 to iso-8859-1. Base64 encoding is defined in RFC 2045.
69 """
70 if not header_bytes:
71 return ""
72 if isinstance(header_bytes, str):
73 header_bytes = header_bytes.encode(charset)
74 encoded = b64encode(header_bytes).decode("ascii")
75 return '=?%s?b?%s?=' % (charset, encoded)
76
77
78 def body_encode(s, maxlinelen=76, eol=NL):
79 r"""Encode a string with base64.
80
81 Each line will be wrapped at, at most, maxlinelen characters (defaults to
82 76 characters).
83
84 Each line of encoded text will end with eol, which defaults to "\n". Set
85 this to "\r\n" if you will be using the result of this function directly
86 in an email.
87 """
88 if not s:
89 return s
90
91 encvec = []
92 max_unencoded = maxlinelen * 3 // 4
93 for i in range(0, len(s), max_unencoded):
94 # BAW: should encode() inherit b2a_base64()'s dubious behavior in
95 # adding a newline to the encoded string?
96 enc = b2a_base64(s[i:i + max_unencoded]).decode("ascii")
97 if enc.endswith(NL) and eol != NL:
98 enc = enc[:-1] + eol
99 encvec.append(enc)
100 return EMPTYSTRING.join(encvec)
101
102
103 def decode(string):
104 """Decode a raw base64 string, returning a bytes object.
105
106 This function does not parse a full MIME header value encoded with
107 base64 (like =?iso-8895-1?b?bmloISBuaWgh?=) -- please use the high
108 level email.header class for that functionality.
109 """
110 if not string:
111 return bytes()
112 elif isinstance(string, str):
113 return a2b_base64(string.encode('raw-unicode-escape'))
114 else:
115 return a2b_base64(string)
116
117
118 # For convenience and backwards compatibility w/ standard base64 module
119 body_decode = decode
120 decodestring = decode