Python code coverage for Lib/email/base64mime.py

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