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c27e52265b
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.
508 lines
21 KiB
Python
508 lines
21 KiB
Python
# Copyright (C) 2004-2006 Python Software Foundation
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# Authors: Baxter, Wouters and Warsaw
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# Contact: email-sig@python.org
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"""FeedParser - An email feed parser.
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The feed parser implements an interface for incrementally parsing an email
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message, line by line. This has advantages for certain applications, such as
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those reading email messages off a socket.
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FeedParser.feed() is the primary interface for pushing new data into the
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parser. It returns when there's nothing more it can do with the available
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data. When you have no more data to push into the parser, call .close().
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This completes the parsing and returns the root message object.
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The other advantage of this parser is that it will never throw a parsing
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exception. Instead, when it finds something unexpected, it adds a 'defect' to
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the current message. Defects are just instances that live on the message
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object's .defects attribute.
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"""
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__all__ = ['FeedParser', 'BytesFeedParser']
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import re
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from email import errors
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from email import message
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from email._policybase import compat32
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NLCRE = re.compile('\r\n|\r|\n')
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NLCRE_bol = re.compile('(\r\n|\r|\n)')
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NLCRE_eol = re.compile('(\r\n|\r|\n)\Z')
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NLCRE_crack = re.compile('(\r\n|\r|\n)')
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# RFC 2822 $3.6.8 Optional fields. ftext is %d33-57 / %d59-126, Any character
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# except controls, SP, and ":".
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headerRE = re.compile(r'^(From |[\041-\071\073-\176]{1,}:|[\t ])')
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EMPTYSTRING = ''
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NL = '\n'
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NeedMoreData = object()
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class BufferedSubFile(object):
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"""A file-ish object that can have new data loaded into it.
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You can also push and pop line-matching predicates onto a stack. When the
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current predicate matches the current line, a false EOF response
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(i.e. empty string) is returned instead. This lets the parser adhere to a
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simple abstraction -- it parses until EOF closes the current message.
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"""
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def __init__(self):
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# The last partial line pushed into this object.
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self._partial = ''
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# The list of full, pushed lines, in reverse order
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self._lines = []
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# The stack of false-EOF checking predicates.
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self._eofstack = []
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# A flag indicating whether the file has been closed or not.
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self._closed = False
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def push_eof_matcher(self, pred):
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self._eofstack.append(pred)
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def pop_eof_matcher(self):
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return self._eofstack.pop()
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def close(self):
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# Don't forget any trailing partial line.
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self._lines.append(self._partial)
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self._partial = ''
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self._closed = True
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def readline(self):
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if not self._lines:
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if self._closed:
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return ''
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return NeedMoreData
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# Pop the line off the stack and see if it matches the current
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# false-EOF predicate.
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line = self._lines.pop()
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# RFC 2046, section 5.1.2 requires us to recognize outer level
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# boundaries at any level of inner nesting. Do this, but be sure it's
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# in the order of most to least nested.
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for ateof in self._eofstack[::-1]:
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if ateof(line):
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# We're at the false EOF. But push the last line back first.
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self._lines.append(line)
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return ''
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return line
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def unreadline(self, line):
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# Let the consumer push a line back into the buffer.
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assert line is not NeedMoreData
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self._lines.append(line)
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def push(self, data):
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"""Push some new data into this object."""
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# Handle any previous leftovers
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data, self._partial = self._partial + data, ''
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# Crack into lines, but preserve the newlines on the end of each
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parts = NLCRE_crack.split(data)
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# The *ahem* interesting behaviour of re.split when supplied grouping
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# parentheses is that the last element of the resulting list is the
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# data after the final RE. In the case of a NL/CR terminated string,
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# this is the empty string.
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self._partial = parts.pop()
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#GAN 29Mar09 bugs 1555570, 1721862 Confusion at 8K boundary ending with \r:
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# is there a \n to follow later?
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if not self._partial and parts and parts[-1].endswith('\r'):
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self._partial = parts.pop(-2)+parts.pop()
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# parts is a list of strings, alternating between the line contents
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# and the eol character(s). Gather up a list of lines after
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# re-attaching the newlines.
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lines = []
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for i in range(len(parts) // 2):
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lines.append(parts[i*2] + parts[i*2+1])
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self.pushlines(lines)
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def pushlines(self, lines):
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# Reverse and insert at the front of the lines.
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self._lines[:0] = lines[::-1]
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def __iter__(self):
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return self
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def __next__(self):
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line = self.readline()
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if line == '':
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raise StopIteration
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return line
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class FeedParser:
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"""A feed-style parser of email."""
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def __init__(self, _factory=message.Message, *, policy=compat32):
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"""_factory is called with no arguments to create a new message obj
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The policy keyword specifies a policy object that controls a number of
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aspects of the parser's operation. The default policy maintains
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backward compatibility.
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"""
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self._factory = _factory
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self.policy = policy
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try:
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_factory(policy=self.policy)
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self._factory_kwds = lambda: {'policy': self.policy}
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except TypeError:
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# Assume this is an old-style factory
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self._factory_kwds = lambda: {}
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self._input = BufferedSubFile()
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self._msgstack = []
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self._parse = self._parsegen().__next__
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self._cur = None
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self._last = None
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self._headersonly = False
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# Non-public interface for supporting Parser's headersonly flag
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def _set_headersonly(self):
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self._headersonly = True
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def feed(self, data):
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"""Push more data into the parser."""
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self._input.push(data)
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self._call_parse()
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def _call_parse(self):
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try:
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self._parse()
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except StopIteration:
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pass
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def close(self):
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"""Parse all remaining data and return the root message object."""
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self._input.close()
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self._call_parse()
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root = self._pop_message()
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assert not self._msgstack
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# Look for final set of defects
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if root.get_content_maintype() == 'multipart' \
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and not root.is_multipart():
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defect = errors.MultipartInvariantViolationDefect()
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self.policy.handle_defect(root, defect)
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return root
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def _new_message(self):
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msg = self._factory(**self._factory_kwds())
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if self._cur and self._cur.get_content_type() == 'multipart/digest':
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msg.set_default_type('message/rfc822')
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if self._msgstack:
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self._msgstack[-1].attach(msg)
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self._msgstack.append(msg)
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self._cur = msg
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self._last = msg
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def _pop_message(self):
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retval = self._msgstack.pop()
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if self._msgstack:
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self._cur = self._msgstack[-1]
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else:
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self._cur = None
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return retval
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def _parsegen(self):
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# Create a new message and start by parsing headers.
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self._new_message()
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headers = []
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# Collect the headers, searching for a line that doesn't match the RFC
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# 2822 header or continuation pattern (including an empty line).
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for line in self._input:
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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if not headerRE.match(line):
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# If we saw the RFC defined header/body separator
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# (i.e. newline), just throw it away. Otherwise the line is
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# part of the body so push it back.
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if not NLCRE.match(line):
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self._input.unreadline(line)
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break
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headers.append(line)
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# Done with the headers, so parse them and figure out what we're
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# supposed to see in the body of the message.
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self._parse_headers(headers)
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# Headers-only parsing is a backwards compatibility hack, which was
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# necessary in the older parser, which could throw errors. All
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# remaining lines in the input are thrown into the message body.
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if self._headersonly:
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lines = []
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while True:
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line = self._input.readline()
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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if line == '':
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break
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lines.append(line)
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self._cur.set_payload(EMPTYSTRING.join(lines))
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return
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if self._cur.get_content_type() == 'message/delivery-status':
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# message/delivery-status contains blocks of headers separated by
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# a blank line. We'll represent each header block as a separate
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# nested message object, but the processing is a bit different
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# than standard message/* types because there is no body for the
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# nested messages. A blank line separates the subparts.
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while True:
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self._input.push_eof_matcher(NLCRE.match)
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for retval in self._parsegen():
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if retval is NeedMoreData:
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yield NeedMoreData
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continue
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break
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msg = self._pop_message()
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# We need to pop the EOF matcher in order to tell if we're at
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# the end of the current file, not the end of the last block
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# of message headers.
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self._input.pop_eof_matcher()
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# The input stream must be sitting at the newline or at the
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# EOF. We want to see if we're at the end of this subpart, so
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# first consume the blank line, then test the next line to see
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# if we're at this subpart's EOF.
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while True:
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line = self._input.readline()
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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break
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while True:
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line = self._input.readline()
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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break
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if line == '':
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break
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# Not at EOF so this is a line we're going to need.
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self._input.unreadline(line)
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return
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if self._cur.get_content_maintype() == 'message':
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# The message claims to be a message/* type, then what follows is
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# another RFC 2822 message.
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for retval in self._parsegen():
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if retval is NeedMoreData:
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yield NeedMoreData
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continue
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break
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self._pop_message()
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return
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if self._cur.get_content_maintype() == 'multipart':
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boundary = self._cur.get_boundary()
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if boundary is None:
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# The message /claims/ to be a multipart but it has not
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# defined a boundary. That's a problem which we'll handle by
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# reading everything until the EOF and marking the message as
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# defective.
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defect = errors.NoBoundaryInMultipartDefect()
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self.policy.handle_defect(self._cur, defect)
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lines = []
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for line in self._input:
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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lines.append(line)
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self._cur.set_payload(EMPTYSTRING.join(lines))
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return
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# Make sure a valid content type was specified per RFC 2045:6.4.
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if (self._cur.get('content-transfer-encoding', '8bit').lower()
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not in ('7bit', '8bit', 'binary')):
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defect = errors.InvalidMultipartContentTransferEncodingDefect()
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self.policy.handle_defect(self._cur, defect)
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# Create a line match predicate which matches the inter-part
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# boundary as well as the end-of-multipart boundary. Don't push
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# this onto the input stream until we've scanned past the
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# preamble.
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separator = '--' + boundary
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boundaryre = re.compile(
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'(?P<sep>' + re.escape(separator) +
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r')(?P<end>--)?(?P<ws>[ \t]*)(?P<linesep>\r\n|\r|\n)?$')
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capturing_preamble = True
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preamble = []
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linesep = False
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while True:
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line = self._input.readline()
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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if line == '':
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break
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mo = boundaryre.match(line)
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if mo:
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# If we're looking at the end boundary, we're done with
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# this multipart. If there was a newline at the end of
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# the closing boundary, then we need to initialize the
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# epilogue with the empty string (see below).
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if mo.group('end'):
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linesep = mo.group('linesep')
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break
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# We saw an inter-part boundary. Were we in the preamble?
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if capturing_preamble:
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if preamble:
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# According to RFC 2046, the last newline belongs
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# to the boundary.
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lastline = preamble[-1]
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eolmo = NLCRE_eol.search(lastline)
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if eolmo:
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preamble[-1] = lastline[:-len(eolmo.group(0))]
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self._cur.preamble = EMPTYSTRING.join(preamble)
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capturing_preamble = False
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self._input.unreadline(line)
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continue
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# We saw a boundary separating two parts. Consume any
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# multiple boundary lines that may be following. Our
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# interpretation of RFC 2046 BNF grammar does not produce
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# body parts within such double boundaries.
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while True:
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line = self._input.readline()
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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mo = boundaryre.match(line)
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if not mo:
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self._input.unreadline(line)
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break
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# Recurse to parse this subpart; the input stream points
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# at the subpart's first line.
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self._input.push_eof_matcher(boundaryre.match)
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for retval in self._parsegen():
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if retval is NeedMoreData:
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yield NeedMoreData
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continue
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break
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# Because of RFC 2046, the newline preceding the boundary
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# separator actually belongs to the boundary, not the
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# previous subpart's payload (or epilogue if the previous
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# part is a multipart).
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if self._last.get_content_maintype() == 'multipart':
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epilogue = self._last.epilogue
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if epilogue == '':
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self._last.epilogue = None
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elif epilogue is not None:
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mo = NLCRE_eol.search(epilogue)
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if mo:
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end = len(mo.group(0))
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self._last.epilogue = epilogue[:-end]
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else:
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payload = self._last._payload
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if isinstance(payload, str):
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mo = NLCRE_eol.search(payload)
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if mo:
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payload = payload[:-len(mo.group(0))]
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self._last._payload = payload
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self._input.pop_eof_matcher()
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self._pop_message()
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# Set the multipart up for newline cleansing, which will
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# happen if we're in a nested multipart.
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self._last = self._cur
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else:
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# I think we must be in the preamble
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assert capturing_preamble
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preamble.append(line)
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# We've seen either the EOF or the end boundary. If we're still
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# capturing the preamble, we never saw the start boundary. Note
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# that as a defect and store the captured text as the payload.
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# Everything from here to the EOF is epilogue.
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if capturing_preamble:
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defect = errors.StartBoundaryNotFoundDefect()
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self.policy.handle_defect(self._cur, defect)
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self._cur.set_payload(EMPTYSTRING.join(preamble))
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epilogue = []
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for line in self._input:
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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self._cur.epilogue = EMPTYSTRING.join(epilogue)
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return
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# If the end boundary ended in a newline, we'll need to make sure
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# the epilogue isn't None
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if linesep:
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epilogue = ['']
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else:
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epilogue = []
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for line in self._input:
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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epilogue.append(line)
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# Any CRLF at the front of the epilogue is not technically part of
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# the epilogue. Also, watch out for an empty string epilogue,
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# which means a single newline.
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if epilogue:
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firstline = epilogue[0]
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bolmo = NLCRE_bol.match(firstline)
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if bolmo:
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epilogue[0] = firstline[len(bolmo.group(0)):]
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self._cur.epilogue = EMPTYSTRING.join(epilogue)
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return
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# Otherwise, it's some non-multipart type, so the entire rest of the
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# file contents becomes the payload.
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lines = []
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for line in self._input:
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if line is NeedMoreData:
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yield NeedMoreData
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continue
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lines.append(line)
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self._cur.set_payload(EMPTYSTRING.join(lines))
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def _parse_headers(self, lines):
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# Passed a list of lines that make up the headers for the current msg
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lastheader = ''
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lastvalue = []
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for lineno, line in enumerate(lines):
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# Check for continuation
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if line[0] in ' \t':
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if not lastheader:
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# The first line of the headers was a continuation. This
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# is illegal, so let's note the defect, store the illegal
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# line, and ignore it for purposes of headers.
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defect = errors.FirstHeaderLineIsContinuationDefect(line)
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self.policy.handle_defect(self._cur, defect)
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continue
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lastvalue.append(line)
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continue
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if lastheader:
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self._cur.set_raw(*self.policy.header_source_parse(lastvalue))
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lastheader, lastvalue = '', []
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# Check for envelope header, i.e. unix-from
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if line.startswith('From '):
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if lineno == 0:
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# Strip off the trailing newline
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mo = NLCRE_eol.search(line)
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if mo:
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line = line[:-len(mo.group(0))]
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self._cur.set_unixfrom(line)
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continue
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elif lineno == len(lines) - 1:
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# Something looking like a unix-from at the end - it's
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# probably the first line of the body, so push back the
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# line and stop.
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self._input.unreadline(line)
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return
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else:
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# Weirdly placed unix-from line. Note this as a defect
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# and ignore it.
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defect = errors.MisplacedEnvelopeHeaderDefect(line)
|
||
self._cur.defects.append(defect)
|
||
continue
|
||
# Split the line on the colon separating field name from value.
|
||
i = line.find(':')
|
||
if i < 0:
|
||
defect = errors.MalformedHeaderDefect(line)
|
||
# XXX: fixme (defect not going through policy)
|
||
self._cur.defects.append(defect)
|
||
continue
|
||
lastheader = line[:i]
|
||
lastvalue = [line]
|
||
# Done with all the lines, so handle the last header.
|
||
if lastheader:
|
||
self._cur.set_raw(*self.policy.header_source_parse(lastvalue))
|
||
|
||
|
||
class BytesFeedParser(FeedParser):
|
||
"""Like FeedParser, but feed accepts bytes."""
|
||
|
||
def feed(self, data):
|
||
super().feed(data.decode('ascii', 'surrogateescape'))
|