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diff --git a/Doc/lib/emailparser.tex b/Doc/lib/emailparser.tex deleted file mode 100644 index 609fa40..0000000 --- a/Doc/lib/emailparser.tex +++ /dev/null @@ -1,208 +0,0 @@ -\declaremodule{standard}{email.parser} -\modulesynopsis{Parse flat text email messages to produce a message - object structure.} - -Message object structures can be created in one of two ways: they can be -created from whole cloth by instantiating \class{Message} objects and -stringing them together via \method{attach()} and -\method{set_payload()} calls, or they can be created by parsing a flat text -representation of the email message. - -The \module{email} package provides a standard parser that understands -most email document structures, including MIME documents. You can -pass the parser a string or a file object, and the parser will return -to you the root \class{Message} instance of the object structure. For -simple, non-MIME messages the payload of this root object will likely -be a string containing the text of the message. For MIME -messages, the root object will return \code{True} from its -\method{is_multipart()} method, and the subparts can be accessed via -the \method{get_payload()} and \method{walk()} methods. - -There are actually two parser interfaces available for use, the classic -\class{Parser} API and the incremental \class{FeedParser} API. The classic -\class{Parser} API is fine if you have the entire text of the message in -memory as a string, or if the entire message lives in a file on the file -system. \class{FeedParser} is more appropriate for when you're reading the -message from a stream which might block waiting for more input (e.g. reading -an email message from a socket). The \class{FeedParser} can consume and parse -the message incrementally, and only returns the root object when you close the -parser\footnote{As of email package version 3.0, introduced in -Python 2.4, the classic \class{Parser} was re-implemented in terms of the -\class{FeedParser}, so the semantics and results are identical between the two -parsers.}. - -Note that the parser can be extended in limited ways, and of course -you can implement your own parser completely from scratch. There is -no magical connection between the \module{email} package's bundled -parser and the \class{Message} class, so your custom parser can create -message object trees any way it finds necessary. - -\subsubsection{FeedParser API} - -\versionadded{2.4} - -The \class{FeedParser}, imported from the \module{email.feedparser} module, -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 -\class{FeedParser} can of course be used to parse an email message fully -contained in a string or a file, but the classic \class{Parser} API may be -more convenient for such use cases. The semantics and results of the two -parser APIs are identical. - -The \class{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 \class{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 \var{defects} -attribute with a list of any problems it found in a message. See the -\refmodule{email.errors} module for the list of defects that it can find. - -Here is the API for the \class{FeedParser}: - -\begin{classdesc}{FeedParser}{\optional{_factory}} -Create a \class{FeedParser} instance. Optional \var{_factory} is a -no-argument callable that will be called whenever a new message object is -needed. It defaults to the \class{email.message.Message} class. -\end{classdesc} - -\begin{methoddesc}[FeedParser]{feed}{data} -Feed the \class{FeedParser} some more data. \var{data} should be a -string containing one or more lines. The lines can be partial and the -\class{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). -\end{methoddesc} - -\begin{methoddesc}[FeedParser]{close}{} -Closing a \class{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 \class{FeedParser}. -\end{methoddesc} - -\subsubsection{Parser class API} - -The \class{Parser} class, imported from the \module{email.parser} module, -provides an API that can be used to parse a message when the complete contents -of the message are available in a string or file. The -\module{email.parser} module also provides a second class, called -\class{HeaderParser} which can be used if you're only interested in -the headers of the message. \class{HeaderParser} can be much faster in -these situations, since it does not attempt to parse the message body, -instead setting the payload to the raw body as a string. -\class{HeaderParser} has the same API as the \class{Parser} class. - -\begin{classdesc}{Parser}{\optional{_class}} -The constructor for the \class{Parser} class takes an optional -argument \var{_class}. This must be a callable factory (such as a -function or a class), and it is used whenever a sub-message object -needs to be created. It defaults to \class{Message} (see -\refmodule{email.message}). The factory will be called without -arguments. - -The optional \var{strict} flag is ignored. \deprecated{2.4}{Because the -\class{Parser} class is a backward compatible API wrapper around the -new-in-Python 2.4 \class{FeedParser}, \emph{all} parsing is effectively -non-strict. You should simply stop passing a \var{strict} flag to the -\class{Parser} constructor.} - -\versionchanged[The \var{strict} flag was added]{2.2.2} -\versionchanged[The \var{strict} flag was deprecated]{2.4} -\end{classdesc} - -The other public \class{Parser} methods are: - -\begin{methoddesc}[Parser]{parse}{fp\optional{, headersonly}} -Read all the data from the file-like object \var{fp}, parse the -resulting text, and return the root message object. \var{fp} must -support both the \method{readline()} and the \method{read()} methods -on file-like objects. - -The text contained in \var{fp} must be formatted as a block of \rfc{2822} -style headers and header continuation lines, optionally preceded by a -envelope header. The header block is terminated either by the -end of the data or by a blank line. Following the header block is the -body of the message (which may contain MIME-encoded subparts). - -Optional \var{headersonly} is as with the \method{parse()} method. - -\versionchanged[The \var{headersonly} flag was added]{2.2.2} -\end{methoddesc} - -\begin{methoddesc}[Parser]{parsestr}{text\optional{, headersonly}} -Similar to the \method{parse()} method, except it takes a string -object instead of a file-like object. Calling this method on a string -is exactly equivalent to wrapping \var{text} in a \class{StringIO} -instance first and calling \method{parse()}. - -Optional \var{headersonly} is a flag specifying whether to stop -parsing after reading the headers or not. The default is \code{False}, -meaning it parses the entire contents of the file. - -\versionchanged[The \var{headersonly} flag was added]{2.2.2} -\end{methoddesc} - -Since creating a message object structure from a string or a file -object is such a common task, two functions are provided as a -convenience. They are available in the top-level \module{email} -package namespace. - -\begin{funcdesc}{message_from_string}{s\optional{, _class\optional{, strict}}} -Return a message object structure from a string. This is exactly -equivalent to \code{Parser().parsestr(s)}. Optional \var{_class} and -\var{strict} are interpreted as with the \class{Parser} class constructor. - -\versionchanged[The \var{strict} flag was added]{2.2.2} -\end{funcdesc} - -\begin{funcdesc}{message_from_file}{fp\optional{, _class\optional{, strict}}} -Return a message object structure tree from an open file object. This -is exactly equivalent to \code{Parser().parse(fp)}. Optional -\var{_class} and \var{strict} are interpreted as with the -\class{Parser} class constructor. - -\versionchanged[The \var{strict} flag was added]{2.2.2} -\end{funcdesc} - -Here's an example of how you might use this at an interactive Python -prompt: - -\begin{verbatim} ->>> import email ->>> msg = email.message_from_string(myString) -\end{verbatim} - -\subsubsection{Additional notes} - -Here are some notes on the parsing semantics: - -\begin{itemize} -\item Most non-\mimetype{multipart} type messages are parsed as a single - message object with a string payload. These objects will return - \code{False} for \method{is_multipart()}. Their - \method{get_payload()} method will return a string object. - -\item All \mimetype{multipart} type messages will be parsed as a - container message object with a list of sub-message objects for - their payload. The outer container message will return - \code{True} for \method{is_multipart()} and their - \method{get_payload()} method will return the list of - \class{Message} subparts. - -\item Most messages with a content type of \mimetype{message/*} - (e.g. \mimetype{message/delivery-status} and - \mimetype{message/rfc822}) will also be parsed as container - object containing a list payload of length 1. Their - \method{is_multipart()} method will return \code{True}. The - single element in the list payload will be a sub-message object. - -\item Some non-standards compliant messages may not be internally consistent - about their \mimetype{multipart}-edness. Such messages may have a - \mailheader{Content-Type} header of type \mimetype{multipart}, but their - \method{is_multipart()} method may return \code{False}. If such - messages were parsed with the \class{FeedParser}, they will have an - instance of the \class{MultipartInvariantViolationDefect} class in their - \var{defects} attribute list. See \refmodule{email.errors} for - details. -\end{itemize} |