2.2.1 FeedParser API

New in version 2.4.

The FeedParser provides an API that is conducive to incremental parsing of email messages, such as would be necessary when reading the text of an email message from a source that can block (e.g. a socket). The FeedParser can of course be used to parse an email message fully contained in a string or a file, but the classic Parser API may be more convenient for such use cases. The semantics and results of the two parser APIs are identical.

The FeedParser's API is simple; you create an instance, feed it a bunch of text until there's no more to feed it, then close the parser to retrieve the root message object. The FeedParser is extremely accurate when parsing standards-compliant messages, and it does a very good job of parsing non-compliant messages, providing information about how a message was deemed broken. It will populate a message object's defects attribute with a list of any problems it found in a message. See the email.Errors module for the list of defects that it can find.

Here is the API for the FeedParser:

class FeedParser( [_factory]): Create a FeedParser instance. Optional _factory is a no-argument callable that will be called whenever a new message object is needed. It defaults to the email.Message.Message class.

feed( data): Feed the FeedParser some more data. data should be a string containing one or more lines. The lines can be partial and the FeedParser will stitch such partial lines together properly. The lines in the string can have any of the common three line endings, carriage return, newline, or carriage return and newline (they can even be mixed).

close( ): Closing a FeedParser completes the parsing of all previously fed data, and returns the root message object. It is undefined what happens if you feed more data to a closed FeedParser.