email.generator.Generator

class email.generator.Generator(outfp, mangle_from_=True, maxheaderlen=78, *, policy=None)

The constructor for the Generator class takes a file-like object called outfp for an argument. outfp must support the write() method and be usable as the output file for the print() function.

Optional mangle_from_ is a flag that, when True, puts a > character in front of any line in the body that starts exactly as From, i.e. From followed by a space at the beginning of the line. This is the only guaranteed portable way to avoid having such lines be mistaken for a Unix mailbox format envelope header separator (see WHY THE CONTENT-LENGTH FORMAT IS BAD for details). mangle_from_ defaults to True, but you might want to set this to False if you are not writing Unix mailbox format files.

Optional maxheaderlen specifies the longest length for a non-continued header. When a header line is longer than maxheaderlen (in characters, with tabs expanded to 8 spaces), the header will be split as defined in the Header class. Set to zero to disable header wrapping. The default is 78, as recommended (but not required) by RFC 2822.

The policy keyword specifies a policy object that controls a number of aspects of the generator’s operation. If no policy is specified, then the policy attached to the message object passed to flatten is used.

The other public Generator methods are:

flatten(msg, unixfrom=False, linesep=None)

Print the textual representation of the message object structure rooted at msg to the output file specified when the Generator instance was created. Subparts are visited depth-first and the resulting text will be properly MIME encoded.

Optional unixfrom is a flag that forces the printing of the envelope header delimiter before the first RFC 2822 header of the root message object. If the root object has no envelope header, a standard one is crafted. By default, this is set to False to inhibit the printing of the envelope delimiter.

Note that for subparts, no envelope header is ever printed.

Optional linesep specifies the line separator character used to terminate lines in the output. If specified it overrides the value specified by the msg‘s or Generator‘s policy.

Because strings cannot represent non-ASCII bytes, if the policy that applies when flatten is run has cte_type set to 8bit, Generator will operate as if it were set to 7bit. This means that messages parsed with a Bytes parser that have a Content-Transfer-Encoding of 8bit will be converted to a use a 7bit Content-Transfer-Encoding. Non-ASCII bytes in the headers will be RFC 2047 encoded with a charset of unknown-8bit.

Changed in version 3.2: Added support for re-encoding 8bit message bodies, and the linesep argument.

clone(fp)

Return an independent clone of this Generator instance with the exact same options.

write(s)

Write the string s to the underlying file object, i.e. outfp passed to Generator‘s constructor. This provides just enough file-like API for Generator instances to be used in the print() function.