diff options
Diffstat (limited to 'Doc/library/email.generator.rst')
| -rw-r--r-- | Doc/library/email.generator.rst | 65 |
1 files changed, 42 insertions, 23 deletions
diff --git a/Doc/library/email.generator.rst b/Doc/library/email.generator.rst index 88c62a2..c172acb 100644 --- a/Doc/library/email.generator.rst +++ b/Doc/library/email.generator.rst @@ -32,7 +32,7 @@ Here are the public methods of the :class:`Generator` class, imported from the :mod:`email.generator` module: -.. class:: Generator(outfp, mangle_from_=True, maxheaderlen=78) +.. class:: Generator(outfp, mangle_from_=True, maxheaderlen=78, *, policy=None) The constructor for the :class:`Generator` class takes a :term:`file-like object` called *outfp* for an argument. *outfp* must support the :meth:`write` method @@ -53,10 +53,17 @@ Here are the public methods of the :class:`Generator` class, imported from the :class:`~email.header.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 :mod:`~email.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 :attr:`flatten` + is used. + + .. versionchanged:: 3.3 Added the *policy* keyword. + The other public :class:`Generator` methods are: - .. method:: flatten(msg, unixfrom=False, linesep='\\n') + .. method:: 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 :class:`Generator` instance @@ -72,19 +79,20 @@ Here are the public methods of the :class:`Generator` class, imported from the Note that for subparts, no envelope header is ever printed. Optional *linesep* specifies the line separator character used to - terminate lines in the output. It defaults to ``\n`` because that is - the most useful value for Python application code (other library packages - expect ``\n`` separated lines). ``linesep=\r\n`` can be used to - generate output with RFC-compliant line separators. + terminate lines in the output. If specified it overrides the value + specified by the *msg*\'s or ``Generator``\'s ``policy``. - Messages parsed with a Bytes parser that have a - :mailheader:`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`. + Because strings cannot represent non-ASCII bytes, if the policy that + applies when ``flatten`` is run has :attr:`~email.policy.Policy.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 :mailheader:`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``. .. versionchanged:: 3.2 - Added support for re-encoding 8bit message bodies, and the *linesep* - argument. + Added support for re-encoding ``8bit`` message bodies, and the + *linesep* argument. .. method:: clone(fp) @@ -103,7 +111,8 @@ As a convenience, see the :class:`~email.message.Message` methods formatted string representation of a message object. For more detail, see :mod:`email.message`. -.. class:: BytesGenerator(outfp, mangle_from_=True, maxheaderlen=78) +.. class:: BytesGenerator(outfp, mangle_from_=True, maxheaderlen=78, *, \ + policy=policy.default) The constructor for the :class:`BytesGenerator` class takes a binary :term:`file-like object` called *outfp* for an argument. *outfp* must @@ -125,19 +134,31 @@ formatted string representation of a message object. For more detail, see wrapping. The default is 78, as recommended (but not required) by :rfc:`2822`. + The *policy* keyword specifies a :mod:`~email.policy` object that controls a + number of aspects of the generator's operation. The default policy + maintains backward compatibility. + + .. versionchanged:: 3.3 Added the *policy* keyword. + The other public :class:`BytesGenerator` methods are: - .. method:: flatten(msg, unixfrom=False, linesep='\n') + .. method:: 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 :class:`BytesGenerator` instance was created. Subparts are visited depth-first and the resulting - text will be properly MIME encoded. If the input that created the *msg* - contained bytes with the high bit set and those bytes have not been - modified, they will be copied faithfully to the output, even if doing so - is not strictly RFC compliant. (To produce strictly RFC compliant - output, use the :class:`Generator` class.) + text will be properly MIME encoded. If the :mod:`~email.policy` option + :attr:`~email.policy.Policy.cte_type` is ``8bit`` (the default), + then any bytes with the high bit set in the original parsed message that + have not been modified will be copied faithfully to the output. If + ``cte_type`` is ``7bit``, the bytes will be converted as needed + using an ASCII-compatible Content-Transfer-Encoding. In particular, + RFC-invalid non-ASCII bytes in headers will be encoded using the MIME + ``unknown-8bit`` character set, thus rendering them RFC-compliant. + + .. XXX: There should be a complementary option that just does the RFC + compliance transformation but leaves CTE 8bit parts alone. Messages parsed with a Bytes parser that have a :mailheader:`Content-Transfer-Encoding` of 8bit will be reconstructed @@ -152,10 +173,8 @@ formatted string representation of a message object. For more detail, see Note that for subparts, no envelope header is ever printed. Optional *linesep* specifies the line separator character used to - terminate lines in the output. It defaults to ``\n`` because that is - the most useful value for Python application code (other library packages - expect ``\n`` separated lines). ``linesep=\r\n`` can be used to - generate output with RFC-compliant line separators. + terminate lines in the output. If specified it overrides the value + specified by the ``Generator``\ 's ``policy``. .. method:: clone(fp) |