# `email.errors`: Exception and Defect classes

ソースコード: Lib/email/errors.py

`email.errors` モジュールでは、以下の例外クラスが定義されています:

exception email.errors.MessageError

  これは `email` パッケージが送出しうるすべての例外の基底クラスです。これは標準の `Exception` クラスから派生しており、追加のメソッドは定義されていません。

exception email.errors.MessageParseError

  This is the base class for exceptions raised by the `Parser` class. It is derived from `MessageError`. This class is also used internally by the parser used by `headerregistry`.

exception email.errors.HeaderParseError

  Raised under some error conditions when parsing the RFC 5322 headers of a message, this class is derived from `MessageParseError`. The `set_boundary()` method will raise this error if the content type is unknown when the method is called. `Header` may raise this error for certain base64 decoding errors, and when an attempt is made to create a header that appears to contain an embedded header (that is, there is what is supposed to be a continuation line that has no leading whitespace and looks like a header).

exception email.errors.BoundaryError

  Deprecated and no longer used.

exception email.errors.MultipartConversionError

  Raised when a payload is added to a `Message` object using `add_payload()`, but the payload is already a scalar and the message's Content-Type main type is not either multipart or missing. `MultipartConversionError` multiply inherits from `MessageError` and the built-in `TypeError`.

  Since `Message.add_payload()` is deprecated, this exception is rarely raised in practice. However the exception may also be raised if the `attach()` method is called on an instance of a class derived from `MIMENonMultipart` (e.g. `MIMEImage`).

exception email.errors.HeaderWriteError

  Raised when an error occurs when the `generator` outputs headers.

exception email.errors.MessageDefect

  This is the base class for all defects found when parsing email messages. It is derived from `ValueError`.

exception email.errors.HeaderDefect

  This is the base class for all defects found when parsing email headers. It is derived from `MessageDefect`.

以下は `FeedParser` がメッセージの解析中に検出する障害 (defect) の一覧です。これらの障害は、問題が見つかったメッセージに追加されるため、たとえば multipart/alternative 内にあるネストしたメッセージが異常なヘッダをもっていた場合には、そのネストしたメッセージが障害を持っているが、その親メッセージには障害はないとみなされることに注意してください。

すべての障害クラスは `email.errors.MessageDefect` のサブクラスです。

- `NoBoundaryInMultipartDefect` -- A message claimed to be a multipart, but had no boundary parameter.

- `StartBoundaryNotFoundDefect` -- The start boundary claimed in the Content-Type header was never found.

- `CloseBoundaryNotFoundDefect` -- A start boundary was found, but no corresponding close boundary was ever found.

  バージョン 3.3 で追加.

- `FirstHeaderLineIsContinuationDefect` -- The message had a continuation line as its first header line.

- `MisplacedEnvelopeHeaderDefect` - A "Unix From" header was found in the middle of a header block.

- `MissingHeaderBodySeparatorDefect` - A line was found while parsing headers that had no leading white space but contained no ':'. Parsing continues assuming that the line represents the first line of the body.

  バージョン 3.3 で追加.

- `MalformedHeaderDefect` -- A header was found that was missing a colon, or was otherwise malformed.

  バージョン 3.3 で非推奨: この欠陥が使われていないPythonバージョンがいくつかあります。

- `MultipartInvariantViolationDefect` -- A message claimed to be a multipart, but no subparts were found. Note that when a message has this defect, its `is_multipart()` method may return `False` even though its content type claims to be multipart.

- `InvalidBase64PaddingDefect` -- When decoding a block of base64 encoded bytes, the padding was not correct. Enough padding is added to perform the decode, but the resulting decoded bytes may be invalid.

- `InvalidBase64CharactersDefect` -- When decoding a block of base64 encoded bytes, characters outside the base64 alphabet were encountered. The characters are ignored, but the resulting decoded bytes may be invalid.

- `InvalidBase64LengthDefect` -- When decoding a block of base64 encoded bytes, the number of non-padding base64 characters was invalid (1 more than a multiple of 4). The encoded block was kept as-is.

- `InvalidDateDefect` -- When decoding an invalid or unparsable date field. The original value is kept as-is.