#14731: refactor email policy framework.
This patch primarily does two things: (1) it adds some internal-interface
methods to Policy that allow for Policy to control the parsing and folding of
headers in such a way that we can construct a backward compatibility policy
that is 100% compatible with the 3.2 API, while allowing a new policy to
implement the email6 API. (2) it adds that backward compatibility policy and
refactors the test suite so that the only differences between the 3.2
test_email.py file and the 3.3 test_email.py file is some small changes in
test framework and the addition of tests for bugs fixed that apply to the 3.2
API.
There are some additional teaks, such as moving just the code needed for the
compatibility policy into _policybase, so that the library code can import
only _policybase. That way the new code that will be added for email6
will only get imported when a non-compatibility policy is imported.
diff --git a/Lib/email/generator.py b/Lib/email/generator.py
index dcfea4c..bfa288b 100644
--- a/Lib/email/generator.py
+++ b/Lib/email/generator.py
@@ -13,9 +13,9 @@
import warnings
from io import StringIO, BytesIO
-from email import policy
+from email._policybase import compat32
from email.header import Header
-from email.message import _has_surrogates
+from email.utils import _has_surrogates
import email.charset as _charset
UNDERSCORE = '_'
@@ -36,7 +36,7 @@
#
def __init__(self, outfp, mangle_from_=True, maxheaderlen=None, *,
- policy=policy.default):
+ policy=None):
"""Create the generator for message flattening.
outfp is the output file-like object for writing the message to. It
@@ -60,8 +60,7 @@
"""
self._fp = outfp
self._mangle_from_ = mangle_from_
- self._maxheaderlen = (maxheaderlen if maxheaderlen is not None else
- policy.max_line_length)
+ self.maxheaderlen = maxheaderlen
self.policy = policy
def write(self, s):
@@ -87,20 +86,33 @@
# from the msg, and _encoded_XXX constants for operating on data that
# has already been converted (to bytes in the BytesGenerator) and
# inserted into a temporary buffer.
- self._NL = linesep if linesep is not None else self.policy.linesep
+ policy = msg.policy if self.policy is None else self.policy
+ if linesep is not None:
+ policy = policy.clone(linesep=linesep)
+ if self.maxheaderlen is not None:
+ policy = policy.clone(max_line_length=self.maxheaderlen)
+ self._NL = policy.linesep
self._encoded_NL = self._encode(self._NL)
self._EMPTY = ''
self._encoded_EMTPY = self._encode('')
- if unixfrom:
- ufrom = msg.get_unixfrom()
- if not ufrom:
- ufrom = 'From nobody ' + time.ctime(time.time())
- self.write(ufrom + self._NL)
- self._write(msg)
+ p = self.policy
+ try:
+ self.policy = policy
+ if unixfrom:
+ ufrom = msg.get_unixfrom()
+ if not ufrom:
+ ufrom = 'From nobody ' + time.ctime(time.time())
+ self.write(ufrom + self._NL)
+ self._write(msg)
+ finally:
+ self.policy = p
def clone(self, fp):
"""Clone this generator with the exact same options."""
- return self.__class__(fp, self._mangle_from_, self._maxheaderlen)
+ return self.__class__(fp,
+ self._mangle_from_,
+ None, # Use policy setting, which we've adjusted
+ policy=self.policy)
#
# Protected interface - undocumented ;/
@@ -175,16 +187,8 @@
#
def _write_headers(self, msg):
- for h, v in msg.items():
- self.write('%s: ' % h)
- if isinstance(v, Header):
- self.write(v.encode(
- maxlinelen=self._maxheaderlen, linesep=self._NL)+self._NL)
- else:
- # Header's got lots of smarts, so use it.
- header = Header(v, maxlinelen=self._maxheaderlen,
- header_name=h)
- self.write(header.encode(linesep=self._NL)+self._NL)
+ for h, v in msg.raw_items():
+ self.write(self.policy.fold(h, v))
# A blank line always separates headers from body
self.write(self._NL)
@@ -265,12 +269,12 @@
# The contents of signed parts has to stay unmodified in order to keep
# the signature intact per RFC1847 2.1, so we disable header wrapping.
# RDM: This isn't enough to completely preserve the part, but it helps.
- old_maxheaderlen = self._maxheaderlen
+ p = self.policy
+ self.policy = p.clone(max_line_length=0)
try:
- self._maxheaderlen = 0
self._handle_multipart(msg)
finally:
- self._maxheaderlen = old_maxheaderlen
+ self.policy = p
def _handle_message_delivery_status(self, msg):
# We can't just write the headers directly to self's file object
@@ -347,9 +351,9 @@
Functionally identical to the base Generator except that the output is
bytes and not string. When surrogates were used in the input to encode
bytes, these are decoded back to bytes for output. If the policy has
- must_be_7bit set true, then the message is transformed such that the
- non-ASCII bytes are properly content transfer encoded, using the
- charset unknown-8bit.
+ cte_type set to 7bit, then the message is transformed such that the
+ non-ASCII bytes are properly content transfer encoded, using the charset
+ unknown-8bit.
The outfp object must accept bytes in its write method.
"""
@@ -370,27 +374,8 @@
def _write_headers(self, msg):
# This is almost the same as the string version, except for handling
# strings with 8bit bytes.
- for h, v in msg._headers:
- self.write('%s: ' % h)
- if isinstance(v, str):
- if _has_surrogates(v):
- if not self.policy.must_be_7bit:
- # If we have raw 8bit data in a byte string, we have no idea
- # what the encoding is. There is no safe way to split this
- # string. If it's ascii-subset, then we could do a normal
- # ascii split, but if it's multibyte then we could break the
- # string. There's no way to know so the least harm seems to
- # be to not split the string and risk it being too long.
- self.write(v+NL)
- continue
- h = Header(v, charset=_charset.UNKNOWN8BIT, header_name=h)
- else:
- h = Header(v, header_name=h)
- else:
- # Assume it is a Header-like object.
- h = v
- self.write(h.encode(linesep=self._NL,
- maxlinelen=self._maxheaderlen)+self._NL)
+ for h, v in msg.raw_items():
+ self._fp.write(self.policy.fold_binary(h, v))
# A blank line always separates headers from body
self.write(self._NL)
@@ -399,7 +384,7 @@
# just write it back out.
if msg._payload is None:
return
- if _has_surrogates(msg._payload) and not self.policy.must_be_7bit:
+ if _has_surrogates(msg._payload) and not self.policy.cte_type=='7bit':
self.write(msg._payload)
else:
super(BytesGenerator,self)._handle_text(msg)