\declaremodule{standard}{email.generator}\modulesynopsis{Generate flat text email messages from a message structure.} One of the most common tasks is to generate the flat text of the emailmessage represented by a message object structure.  You will need to dothis if you want to send your message via the \refmodule{smtplib}module or the \refmodule{nntplib} module, or print the message on theconsole.  Taking a message object structure and producing a flat textdocument is the job of the \class{Generator} class. Again, as with the \refmodule{email.parser} module, you aren't limitedto the functionality of the bundled generator; you could write onefrom scratch yourself.  However the bundled generator knows how togenerate most email in a standards-compliant way, should handle MIMEand non-MIME email messages just fine, and is designed so that thetransformation from flat text, to a message structure via the\class{Parser} class, and back to flat text, is idempotent (the inputis identical to the output). Here are the public methods of the \class{Generator} class, imported from the\module{email.generator} module: \begin{classdesc}{Generator}{outfp\optional{, mangle_from_\optional{,    maxheaderlen}}}The constructor for the \class{Generator} class takes a file-likeobject called \var{outfp} for an argument.  \var{outfp} must supportthe \method{write()} method and be usable as the output file in aPython extended print statement. Optional \var{mangle_from_} is a flag that, when \code{True}, puts a\samp{>} character in front of any line in the body that starts exactly as\samp{From }, i.e. \code{From} followed by a space at the beginning of theline.  This is the only guaranteed portable way to avoid having suchlines be mistaken for a \UNIX{} mailbox format envelope header separator (see\ulink{WHY THE CONTENT-LENGTH FORMAT IS BAD}{http://www.jwz.org/doc/content-length.html}for details).  \var{mangle_from_} defaults to \code{True}, but youmight want to set this to \code{False} if you are not writing \UNIX{}mailbox format files. Optional \var{maxheaderlen} specifies the longest length for anon-continued header.  When a header line is longer than\var{maxheaderlen} (in characters, with tabs expanded to 8 spaces),the header will be split as defined in the \module{email.header.Header}class.  Set to zero to disable header wrapping.  The default is 78, asrecommended (but not required) by \rfc{2822}.\end{classdesc} The other public \class{Generator} methods are: \begin{methoddesc}[Generator]{flatten}{msg\optional{, unixfrom}}Print the textual representation of the message object structure rooted at\var{msg} to the output file specified when the \class{Generator}instance was created.  Subparts are visited depth-first and theresulting text will be properly MIME encoded. Optional \var{unixfrom} is a flag that forces the printing of theenvelope header delimiter before the first \rfc{2822} header of theroot message object.  If the root object has no envelope header, astandard one is crafted.  By default, this is set to \code{False} toinhibit the printing of the envelope delimiter. Note that for subparts, no envelope header is ever printed. \versionadded{2.2.2}\end{methoddesc} \begin{methoddesc}[Generator]{clone}{fp}Return an independent clone of this \class{Generator} instance withthe exact same options. \versionadded{2.2.2}\end{methoddesc} \begin{methoddesc}[Generator]{write}{s}Write the string \var{s} to the underlying file object,i.e. \var{outfp} passed to \class{Generator}'s constructor.  Thisprovides just enough file-like API for \class{Generator} instances tobe used in extended print statements.\end{methoddesc} As a convenience, see the methods \method{Message.as_string()} and\code{str(aMessage)}, a.k.a. \method{Message.__str__()}, whichsimplify the generation of a formatted string representation of amessage object.  For more detail, see \refmodule{email.message}. The \module{email.generator} module also provides a derived class,called \class{DecodedGenerator} which is like the \class{Generator}base class, except that non-\mimetype{text} parts are substituted witha format string representing the part. \begin{classdesc}{DecodedGenerator}{outfp\optional{, mangle_from_\optional{,    maxheaderlen\optional{, fmt}}}} This class, derived from \class{Generator} walks through all thesubparts of a message.  If the subpart is of main type\mimetype{text}, then it prints the decoded payload of the subpart.Optional \var{_mangle_from_} and \var{maxheaderlen} are as with the\class{Generator} base class. If the subpart is not of main type \mimetype{text}, optional \var{fmt}is a format string that is used instead of the message payload.\var{fmt} is expanded with the following keywords, \samp{\%(keyword)s}format: \begin{itemize}\item \code{type} -- Full MIME type of the non-\mimetype{text} part \item \code{maintype} -- Main MIME type of the non-\mimetype{text} part \item \code{subtype} -- Sub-MIME type of the non-\mimetype{text} part \item \code{filename} -- Filename of the non-\mimetype{text} part \item \code{description} -- Description associated with the      non-\mimetype{text} part \item \code{encoding} -- Content transfer encoding of the      non-\mimetype{text} part \end{itemize} The default value for \var{fmt} is \code{None}, meaning \begin{verbatim}[Non-text (%(type)s) part of message omitted, filename %(filename)s]\end{verbatim} \versionadded{2.2.2}\end{classdesc} \versionchanged[The previously deprecated method \method{__call__()} wasremoved]{2.5}