1:mod:`!email.errors`: Exception and Defect classes 2-------------------------------------------------- 3 4.. module:: email.errors 5 :synopsis: The exception classes used by the email package. 6 7**Source code:** :source:`Lib/email/errors.py` 8 9-------------- 10 11The following exception classes are defined in the :mod:`email.errors` module: 12 13 14.. exception:: MessageError() 15 16 This is the base class for all exceptions that the :mod:`email` package can 17 raise. It is derived from the standard :exc:`Exception` class and defines no 18 additional methods. 19 20 21.. exception:: MessageParseError() 22 23 This is the base class for exceptions raised by the 24 :class:`~email.parser.Parser` class. It is derived from 25 :exc:`MessageError`. This class is also used internally by the parser used 26 by :mod:`~email.headerregistry`. 27 28 29.. exception:: HeaderParseError() 30 31 Raised under some error conditions when parsing the :rfc:`5322` headers of a 32 message, this class is derived from :exc:`MessageParseError`. The 33 :meth:`~email.message.EmailMessage.set_boundary` method will raise this 34 error if the content type is unknown when the method is called. 35 :class:`~email.header.Header` may raise this error for certain base64 36 decoding errors, and when an attempt is made to create a header that appears 37 to contain an embedded header (that is, there is what is supposed to be a 38 continuation line that has no leading whitespace and looks like a header). 39 40 41.. exception:: BoundaryError() 42 43 Deprecated and no longer used. 44 45 46.. exception:: MultipartConversionError() 47 48 Raised when a payload is added to a :class:`~email.message.Message` object 49 using :meth:`add_payload`, but the payload is already a scalar and the 50 message's :mailheader:`Content-Type` main type is not either 51 :mimetype:`multipart` or missing. :exc:`MultipartConversionError` multiply 52 inherits from :exc:`MessageError` and the built-in :exc:`TypeError`. 53 54 Since :meth:`Message.add_payload` is deprecated, this exception is rarely 55 raised in practice. However the exception may also be raised if the 56 :meth:`~email.message.Message.attach` 57 method is called on an instance of a class derived from 58 :class:`~email.mime.nonmultipart.MIMENonMultipart` (e.g. 59 :class:`~email.mime.image.MIMEImage`). 60 61 62.. exception:: HeaderWriteError() 63 64 Raised when an error occurs when the :mod:`~email.generator` outputs 65 headers. 66 67 68.. exception:: MessageDefect() 69 70 This is the base class for all defects found when parsing email messages. 71 It is derived from :exc:`ValueError`. 72 73.. exception:: HeaderDefect() 74 75 This is the base class for all defects found when parsing email headers. 76 It is derived from :exc:`MessageDefect`. 77 78Here is the list of the defects that the :class:`~email.parser.FeedParser` 79can find while parsing messages. Note that the defects are added to the message 80where the problem was found, so for example, if a message nested inside a 81:mimetype:`multipart/alternative` had a malformed header, that nested message 82object would have a defect, but the containing messages would not. 83 84All defect classes are subclassed from :class:`email.errors.MessageDefect`. 85 86* :class:`NoBoundaryInMultipartDefect` -- A message claimed to be a multipart, 87 but had no :mimetype:`boundary` parameter. 88 89* :class:`StartBoundaryNotFoundDefect` -- The start boundary claimed in the 90 :mailheader:`Content-Type` header was never found. 91 92* :class:`CloseBoundaryNotFoundDefect` -- A start boundary was found, but 93 no corresponding close boundary was ever found. 94 95 .. versionadded:: 3.3 96 97* :class:`FirstHeaderLineIsContinuationDefect` -- The message had a continuation 98 line as its first header line. 99 100* :class:`MisplacedEnvelopeHeaderDefect` - A "Unix From" header was found in the 101 middle of a header block. 102 103* :class:`MissingHeaderBodySeparatorDefect` - A line was found while parsing 104 headers that had no leading white space but contained no ':'. Parsing 105 continues assuming that the line represents the first line of the body. 106 107 .. versionadded:: 3.3 108 109* :class:`MalformedHeaderDefect` -- A header was found that was missing a colon, 110 or was otherwise malformed. 111 112 .. deprecated:: 3.3 113 This defect has not been used for several Python versions. 114 115* :class:`MultipartInvariantViolationDefect` -- A message claimed to be a 116 :mimetype:`multipart`, but no subparts were found. Note that when a message 117 has this defect, its :meth:`~email.message.Message.is_multipart` method may 118 return ``False`` even though its content type claims to be :mimetype:`multipart`. 119 120* :class:`InvalidBase64PaddingDefect` -- When decoding a block of base64 121 encoded bytes, the padding was not correct. Enough padding is added to 122 perform the decode, but the resulting decoded bytes may be invalid. 123 124* :class:`InvalidBase64CharactersDefect` -- When decoding a block of base64 125 encoded bytes, characters outside the base64 alphabet were encountered. 126 The characters are ignored, but the resulting decoded bytes may be invalid. 127 128* :class:`InvalidBase64LengthDefect` -- When decoding a block of base64 encoded 129 bytes, the number of non-padding base64 characters was invalid (1 more than 130 a multiple of 4). The encoded block was kept as-is. 131 132* :class:`InvalidDateDefect` -- When decoding an invalid or unparsable date field. 133 The original value is kept as-is. 134