python (3.12.0)
1 # Copyright (C) 2001-2006 Python Software Foundation
2 # Author: Barry Warsaw
3 # Contact: email-sig@python.org
4
5 """Class representing image/* type MIME documents."""
6
7 __all__ = ['MIMEImage']
8
9 from email import encoders
10 from email.mime.nonmultipart import MIMENonMultipart
11
12
13 class ESC[4;38;5;81mMIMEImage(ESC[4;38;5;149mMIMENonMultipart):
14 """Class for generating image/* type MIME documents."""
15
16 def __init__(self, _imagedata, _subtype=None,
17 _encoder=encoders.encode_base64, *, policy=None, **_params):
18 """Create an image/* type MIME document.
19
20 _imagedata contains the bytes for the raw image data. If the data
21 type can be detected (jpeg, png, gif, tiff, rgb, pbm, pgm, ppm,
22 rast, xbm, bmp, webp, and exr attempted), then the subtype will be
23 automatically included in the Content-Type header. Otherwise, you can
24 specify the specific image subtype via the _subtype parameter.
25
26 _encoder is a function which will perform the actual encoding for
27 transport of the image data. It takes one argument, which is this
28 Image instance. It should use get_payload() and set_payload() to
29 change the payload to the encoded form. It should also add any
30 Content-Transfer-Encoding or other headers to the message as
31 necessary. The default encoding is Base64.
32
33 Any additional keyword arguments are passed to the base class
34 constructor, which turns them into parameters on the Content-Type
35 header.
36 """
37 _subtype = _what(_imagedata) if _subtype is None else _subtype
38 if _subtype is None:
39 raise TypeError('Could not guess image MIME subtype')
40 MIMENonMultipart.__init__(self, 'image', _subtype, policy=policy,
41 **_params)
42 self.set_payload(_imagedata)
43 _encoder(self)
44
45
46 _rules = []
47
48
49 # Originally from the imghdr module.
50 def _what(data):
51 for rule in _rules:
52 if res := rule(data):
53 return res
54 else:
55 return None
56
57
58 def rule(rulefunc):
59 _rules.append(rulefunc)
60 return rulefunc
61
62
63 @rule
64 def _jpeg(h):
65 """JPEG data with JFIF or Exif markers; and raw JPEG"""
66 if h[6:10] in (b'JFIF', b'Exif'):
67 return 'jpeg'
68 elif h[:4] == b'\xff\xd8\xff\xdb':
69 return 'jpeg'
70
71
72 @rule
73 def _png(h):
74 if h.startswith(b'\211PNG\r\n\032\n'):
75 return 'png'
76
77
78 @rule
79 def _gif(h):
80 """GIF ('87 and '89 variants)"""
81 if h[:6] in (b'GIF87a', b'GIF89a'):
82 return 'gif'
83
84
85 @rule
86 def _tiff(h):
87 """TIFF (can be in Motorola or Intel byte order)"""
88 if h[:2] in (b'MM', b'II'):
89 return 'tiff'
90
91
92 @rule
93 def _rgb(h):
94 """SGI image library"""
95 if h.startswith(b'\001\332'):
96 return 'rgb'
97
98
99 @rule
100 def _pbm(h):
101 """PBM (portable bitmap)"""
102 if len(h) >= 3 and \
103 h[0] == ord(b'P') and h[1] in b'14' and h[2] in b' \t\n\r':
104 return 'pbm'
105
106
107 @rule
108 def _pgm(h):
109 """PGM (portable graymap)"""
110 if len(h) >= 3 and \
111 h[0] == ord(b'P') and h[1] in b'25' and h[2] in b' \t\n\r':
112 return 'pgm'
113
114
115 @rule
116 def _ppm(h):
117 """PPM (portable pixmap)"""
118 if len(h) >= 3 and \
119 h[0] == ord(b'P') and h[1] in b'36' and h[2] in b' \t\n\r':
120 return 'ppm'
121
122
123 @rule
124 def _rast(h):
125 """Sun raster file"""
126 if h.startswith(b'\x59\xA6\x6A\x95'):
127 return 'rast'
128
129
130 @rule
131 def _xbm(h):
132 """X bitmap (X10 or X11)"""
133 if h.startswith(b'#define '):
134 return 'xbm'
135
136
137 @rule
138 def _bmp(h):
139 if h.startswith(b'BM'):
140 return 'bmp'
141
142
143 @rule
144 def _webp(h):
145 if h.startswith(b'RIFF') and h[8:12] == b'WEBP':
146 return 'webp'
147
148
149 @rule
150 def _exr(h):
151 if h.startswith(b'\x76\x2f\x31\x01'):
152 return 'exr'
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