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"""Class representing image/* type MIME documents.""" |
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__all__ = ['MIMEImage'] |
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from email import encoders |
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from email.mime.nonmultipart import MIMENonMultipart |
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class MIMEImage(MIMENonMultipart): |
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"""Class for generating image/* type MIME documents.""" |
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def __init__(self, _imagedata, _subtype=None, |
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_encoder=encoders.encode_base64, *, policy=None, **_params): |
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"""Create an image/* type MIME document. |
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_imagedata contains the bytes for the raw image data. If the data |
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type can be detected (jpeg, png, gif, tiff, rgb, pbm, pgm, ppm, |
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rast, xbm, bmp, webp, and exr attempted), then the subtype will be |
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automatically included in the Content-Type header. Otherwise, you can |
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specify the specific image subtype via the _subtype parameter. |
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_encoder is a function which will perform the actual encoding for |
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transport of the image data. It takes one argument, which is this |
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Image instance. It should use get_payload() and set_payload() to |
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change the payload to the encoded form. It should also add any |
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Content-Transfer-Encoding or other headers to the message as |
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necessary. The default encoding is Base64. |
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Any additional keyword arguments are passed to the base class |
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constructor, which turns them into parameters on the Content-Type |
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header. |
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""" |
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_subtype = _what(_imagedata) if _subtype is None else _subtype |
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if _subtype is None: |
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raise TypeError('Could not guess image MIME subtype') |
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MIMENonMultipart.__init__(self, 'image', _subtype, policy=policy, |
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**_params) |
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self.set_payload(_imagedata) |
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_encoder(self) |
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_rules = [] |
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def _what(data): |
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for rule in _rules: |
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if res := rule(data): |
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return res |
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else: |
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return None |
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def rule(rulefunc): |
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_rules.append(rulefunc) |
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return rulefunc |
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@rule |
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def _jpeg(h): |
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"""JPEG data with JFIF or Exif markers; and raw JPEG""" |
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if h[6:10] in (b'JFIF', b'Exif'): |
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return 'jpeg' |
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elif h[:4] == b'\xff\xd8\xff\xdb': |
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return 'jpeg' |
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@rule |
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def _png(h): |
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if h.startswith(b'\211PNG\r\n\032\n'): |
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return 'png' |
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@rule |
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def _gif(h): |
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"""GIF ('87 and '89 variants)""" |
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if h[:6] in (b'GIF87a', b'GIF89a'): |
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return 'gif' |
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@rule |
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def _tiff(h): |
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"""TIFF (can be in Motorola or Intel byte order)""" |
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if h[:2] in (b'MM', b'II'): |
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return 'tiff' |
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@rule |
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def _rgb(h): |
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"""SGI image library""" |
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if h.startswith(b'\001\332'): |
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return 'rgb' |
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@rule |
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def _pbm(h): |
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"""PBM (portable bitmap)""" |
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if len(h) >= 3 and \ |
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h[0] == ord(b'P') and h[1] in b'14' and h[2] in b' \t\n\r': |
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return 'pbm' |
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@rule |
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def _pgm(h): |
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"""PGM (portable graymap)""" |
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if len(h) >= 3 and \ |
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h[0] == ord(b'P') and h[1] in b'25' and h[2] in b' \t\n\r': |
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return 'pgm' |
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@rule |
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def _ppm(h): |
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"""PPM (portable pixmap)""" |
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if len(h) >= 3 and \ |
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h[0] == ord(b'P') and h[1] in b'36' and h[2] in b' \t\n\r': |
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return 'ppm' |
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@rule |
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def _rast(h): |
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"""Sun raster file""" |
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if h.startswith(b'\x59\xA6\x6A\x95'): |
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return 'rast' |
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@rule |
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def _xbm(h): |
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"""X bitmap (X10 or X11)""" |
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if h.startswith(b'#define '): |
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return 'xbm' |
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@rule |
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def _bmp(h): |
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if h.startswith(b'BM'): |
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return 'bmp' |
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@rule |
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def _webp(h): |
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if h.startswith(b'RIFF') and h[8:12] == b'WEBP': |
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return 'webp' |
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@rule |
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def _exr(h): |
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if h.startswith(b'\x76\x2f\x31\x01'): |
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return 'exr' |
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