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authorThomas Wouters <thomas@python.org>2006-04-21 10:40:58 (GMT)
committerThomas Wouters <thomas@python.org>2006-04-21 10:40:58 (GMT)
commit49fd7fa4431da299196d74087df4a04f99f9c46f (patch)
tree35ace5fe78d3d52c7a9ab356ab9f6dbf8d4b71f4 /Lib/email/feedparser.py
parent9ada3d6e29d5165dadacbe6be07bcd35cfbef59d (diff)
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Merge p3yk branch with the trunk up to revision 45595. This breaks a fair
number of tests, all because of the codecs/_multibytecodecs issue described here (it's not a Py3K issue, just something Py3K discovers): http://mail.python.org/pipermail/python-dev/2006-April/064051.html Hye-Shik Chang promised to look for a fix, so no need to fix it here. The tests that are expected to break are: test_codecencodings_cn test_codecencodings_hk test_codecencodings_jp test_codecencodings_kr test_codecencodings_tw test_codecs test_multibytecodec This merge fixes an actual test failure (test_weakref) in this branch, though, so I believe merging is the right thing to do anyway.
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diff --git a/Lib/email/feedparser.py b/Lib/email/feedparser.py
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+# Copyright (C) 2004-2006 Python Software Foundation
+# Authors: Baxter, Wouters and Warsaw
+# Contact: email-sig@python.org
+
+"""FeedParser - An email feed parser.
+
+The feed parser implements an interface for incrementally parsing an email
+message, line by line. This has advantages for certain applications, such as
+those reading email messages off a socket.
+
+FeedParser.feed() is the primary interface for pushing new data into the
+parser. It returns when there's nothing more it can do with the available
+data. When you have no more data to push into the parser, call .close().
+This completes the parsing and returns the root message object.
+
+The other advantage of this parser is that it will never throw a parsing
+exception. Instead, when it finds something unexpected, it adds a 'defect' to
+the current message. Defects are just instances that live on the message
+object's .defects attribute.
+"""
+
+__all__ = ['FeedParser']
+
+import re
+
+from email import errors
+from email import message
+
+NLCRE = re.compile('\r\n|\r|\n')
+NLCRE_bol = re.compile('(\r\n|\r|\n)')
+NLCRE_eol = re.compile('(\r\n|\r|\n)$')
+NLCRE_crack = re.compile('(\r\n|\r|\n)')
+# RFC 2822 $3.6.8 Optional fields. ftext is %d33-57 / %d59-126, Any character
+# except controls, SP, and ":".
+headerRE = re.compile(r'^(From |[\041-\071\073-\176]{1,}:|[\t ])')
+EMPTYSTRING = ''
+NL = '\n'
+
+NeedMoreData = object()
+
+
+
+class BufferedSubFile(object):
+ """A file-ish object that can have new data loaded into it.
+
+ You can also push and pop line-matching predicates onto a stack. When the
+ current predicate matches the current line, a false EOF response
+ (i.e. empty string) is returned instead. This lets the parser adhere to a
+ simple abstraction -- it parses until EOF closes the current message.
+ """
+ def __init__(self):
+ # The last partial line pushed into this object.
+ self._partial = ''
+ # The list of full, pushed lines, in reverse order
+ self._lines = []
+ # The stack of false-EOF checking predicates.
+ self._eofstack = []
+ # A flag indicating whether the file has been closed or not.
+ self._closed = False
+
+ def push_eof_matcher(self, pred):
+ self._eofstack.append(pred)
+
+ def pop_eof_matcher(self):
+ return self._eofstack.pop()
+
+ def close(self):
+ # Don't forget any trailing partial line.
+ self._lines.append(self._partial)
+ self._partial = ''
+ self._closed = True
+
+ def readline(self):
+ if not self._lines:
+ if self._closed:
+ return ''
+ return NeedMoreData
+ # Pop the line off the stack and see if it matches the current
+ # false-EOF predicate.
+ line = self._lines.pop()
+ # RFC 2046, section 5.1.2 requires us to recognize outer level
+ # boundaries at any level of inner nesting. Do this, but be sure it's
+ # in the order of most to least nested.
+ for ateof in self._eofstack[::-1]:
+ if ateof(line):
+ # We're at the false EOF. But push the last line back first.
+ self._lines.append(line)
+ return ''
+ return line
+
+ def unreadline(self, line):
+ # Let the consumer push a line back into the buffer.
+ assert line is not NeedMoreData
+ self._lines.append(line)
+
+ def push(self, data):
+ """Push some new data into this object."""
+ # Handle any previous leftovers
+ data, self._partial = self._partial + data, ''
+ # Crack into lines, but preserve the newlines on the end of each
+ parts = NLCRE_crack.split(data)
+ # The *ahem* interesting behaviour of re.split when supplied grouping
+ # parentheses is that the last element of the resulting list is the
+ # data after the final RE. In the case of a NL/CR terminated string,
+ # this is the empty string.
+ self._partial = parts.pop()
+ # parts is a list of strings, alternating between the line contents
+ # and the eol character(s). Gather up a list of lines after
+ # re-attaching the newlines.
+ lines = []
+ for i in range(len(parts) // 2):
+ lines.append(parts[i*2] + parts[i*2+1])
+ self.pushlines(lines)
+
+ def pushlines(self, lines):
+ # Reverse and insert at the front of the lines.
+ self._lines[:0] = lines[::-1]
+
+ def is_closed(self):
+ return self._closed
+
+ def __iter__(self):
+ return self
+
+ def next(self):
+ line = self.readline()
+ if line == '':
+ raise StopIteration
+ return line
+
+
+
+class FeedParser:
+ """A feed-style parser of email."""
+
+ def __init__(self, _factory=message.Message):
+ """_factory is called with no arguments to create a new message obj"""
+ self._factory = _factory
+ self._input = BufferedSubFile()
+ self._msgstack = []
+ self._parse = self._parsegen().next
+ self._cur = None
+ self._last = None
+ self._headersonly = False
+
+ # Non-public interface for supporting Parser's headersonly flag
+ def _set_headersonly(self):
+ self._headersonly = True
+
+ def feed(self, data):
+ """Push more data into the parser."""
+ self._input.push(data)
+ self._call_parse()
+
+ def _call_parse(self):
+ try:
+ self._parse()
+ except StopIteration:
+ pass
+
+ def close(self):
+ """Parse all remaining data and return the root message object."""
+ self._input.close()
+ self._call_parse()
+ root = self._pop_message()
+ assert not self._msgstack
+ # Look for final set of defects
+ if root.get_content_maintype() == 'multipart' \
+ and not root.is_multipart():
+ root.defects.append(errors.MultipartInvariantViolationDefect())
+ return root
+
+ def _new_message(self):
+ msg = self._factory()
+ if self._cur and self._cur.get_content_type() == 'multipart/digest':
+ msg.set_default_type('message/rfc822')
+ if self._msgstack:
+ self._msgstack[-1].attach(msg)
+ self._msgstack.append(msg)
+ self._cur = msg
+ self._last = msg
+
+ def _pop_message(self):
+ retval = self._msgstack.pop()
+ if self._msgstack:
+ self._cur = self._msgstack[-1]
+ else:
+ self._cur = None
+ return retval
+
+ def _parsegen(self):
+ # Create a new message and start by parsing headers.
+ self._new_message()
+ headers = []
+ # Collect the headers, searching for a line that doesn't match the RFC
+ # 2822 header or continuation pattern (including an empty line).
+ for line in self._input:
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ if not headerRE.match(line):
+ # If we saw the RFC defined header/body separator
+ # (i.e. newline), just throw it away. Otherwise the line is
+ # part of the body so push it back.
+ if not NLCRE.match(line):
+ self._input.unreadline(line)
+ break
+ headers.append(line)
+ # Done with the headers, so parse them and figure out what we're
+ # supposed to see in the body of the message.
+ self._parse_headers(headers)
+ # Headers-only parsing is a backwards compatibility hack, which was
+ # necessary in the older parser, which could throw errors. All
+ # remaining lines in the input are thrown into the message body.
+ if self._headersonly:
+ lines = []
+ while True:
+ line = self._input.readline()
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ if line == '':
+ break
+ lines.append(line)
+ self._cur.set_payload(EMPTYSTRING.join(lines))
+ return
+ if self._cur.get_content_type() == 'message/delivery-status':
+ # message/delivery-status contains blocks of headers separated by
+ # a blank line. We'll represent each header block as a separate
+ # nested message object, but the processing is a bit different
+ # than standard message/* types because there is no body for the
+ # nested messages. A blank line separates the subparts.
+ while True:
+ self._input.push_eof_matcher(NLCRE.match)
+ for retval in self._parsegen():
+ if retval is NeedMoreData:
+ yield NeedMoreData
+ continue
+ break
+ msg = self._pop_message()
+ # We need to pop the EOF matcher in order to tell if we're at
+ # the end of the current file, not the end of the last block
+ # of message headers.
+ self._input.pop_eof_matcher()
+ # The input stream must be sitting at the newline or at the
+ # EOF. We want to see if we're at the end of this subpart, so
+ # first consume the blank line, then test the next line to see
+ # if we're at this subpart's EOF.
+ while True:
+ line = self._input.readline()
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ break
+ while True:
+ line = self._input.readline()
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ break
+ if line == '':
+ break
+ # Not at EOF so this is a line we're going to need.
+ self._input.unreadline(line)
+ return
+ if self._cur.get_content_maintype() == 'message':
+ # The message claims to be a message/* type, then what follows is
+ # another RFC 2822 message.
+ for retval in self._parsegen():
+ if retval is NeedMoreData:
+ yield NeedMoreData
+ continue
+ break
+ self._pop_message()
+ return
+ if self._cur.get_content_maintype() == 'multipart':
+ boundary = self._cur.get_boundary()
+ if boundary is None:
+ # The message /claims/ to be a multipart but it has not
+ # defined a boundary. That's a problem which we'll handle by
+ # reading everything until the EOF and marking the message as
+ # defective.
+ self._cur.defects.append(errors.NoBoundaryInMultipartDefect())
+ lines = []
+ for line in self._input:
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ lines.append(line)
+ self._cur.set_payload(EMPTYSTRING.join(lines))
+ return
+ # Create a line match predicate which matches the inter-part
+ # boundary as well as the end-of-multipart boundary. Don't push
+ # this onto the input stream until we've scanned past the
+ # preamble.
+ separator = '--' + boundary
+ boundaryre = re.compile(
+ '(?P<sep>' + re.escape(separator) +
+ r')(?P<end>--)?(?P<ws>[ \t]*)(?P<linesep>\r\n|\r|\n)?$')
+ capturing_preamble = True
+ preamble = []
+ linesep = False
+ while True:
+ line = self._input.readline()
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ if line == '':
+ break
+ mo = boundaryre.match(line)
+ if mo:
+ # If we're looking at the end boundary, we're done with
+ # this multipart. If there was a newline at the end of
+ # the closing boundary, then we need to initialize the
+ # epilogue with the empty string (see below).
+ if mo.group('end'):
+ linesep = mo.group('linesep')
+ break
+ # We saw an inter-part boundary. Were we in the preamble?
+ if capturing_preamble:
+ if preamble:
+ # According to RFC 2046, the last newline belongs
+ # to the boundary.
+ lastline = preamble[-1]
+ eolmo = NLCRE_eol.search(lastline)
+ if eolmo:
+ preamble[-1] = lastline[:-len(eolmo.group(0))]
+ self._cur.preamble = EMPTYSTRING.join(preamble)
+ capturing_preamble = False
+ self._input.unreadline(line)
+ continue
+ # We saw a boundary separating two parts. Consume any
+ # multiple boundary lines that may be following. Our
+ # interpretation of RFC 2046 BNF grammar does not produce
+ # body parts within such double boundaries.
+ while True:
+ line = self._input.readline()
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ mo = boundaryre.match(line)
+ if not mo:
+ self._input.unreadline(line)
+ break
+ # Recurse to parse this subpart; the input stream points
+ # at the subpart's first line.
+ self._input.push_eof_matcher(boundaryre.match)
+ for retval in self._parsegen():
+ if retval is NeedMoreData:
+ yield NeedMoreData
+ continue
+ break
+ # Because of RFC 2046, the newline preceding the boundary
+ # separator actually belongs to the boundary, not the
+ # previous subpart's payload (or epilogue if the previous
+ # part is a multipart).
+ if self._last.get_content_maintype() == 'multipart':
+ epilogue = self._last.epilogue
+ if epilogue == '':
+ self._last.epilogue = None
+ elif epilogue is not None:
+ mo = NLCRE_eol.search(epilogue)
+ if mo:
+ end = len(mo.group(0))
+ self._last.epilogue = epilogue[:-end]
+ else:
+ payload = self._last.get_payload()
+ if isinstance(payload, basestring):
+ mo = NLCRE_eol.search(payload)
+ if mo:
+ payload = payload[:-len(mo.group(0))]
+ self._last.set_payload(payload)
+ self._input.pop_eof_matcher()
+ self._pop_message()
+ # Set the multipart up for newline cleansing, which will
+ # happen if we're in a nested multipart.
+ self._last = self._cur
+ else:
+ # I think we must be in the preamble
+ assert capturing_preamble
+ preamble.append(line)
+ # We've seen either the EOF or the end boundary. If we're still
+ # capturing the preamble, we never saw the start boundary. Note
+ # that as a defect and store the captured text as the payload.
+ # Everything from here to the EOF is epilogue.
+ if capturing_preamble:
+ self._cur.defects.append(errors.StartBoundaryNotFoundDefect())
+ self._cur.set_payload(EMPTYSTRING.join(preamble))
+ epilogue = []
+ for line in self._input:
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ self._cur.epilogue = EMPTYSTRING.join(epilogue)
+ return
+ # If the end boundary ended in a newline, we'll need to make sure
+ # the epilogue isn't None
+ if linesep:
+ epilogue = ['']
+ else:
+ epilogue = []
+ for line in self._input:
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ epilogue.append(line)
+ # Any CRLF at the front of the epilogue is not technically part of
+ # the epilogue. Also, watch out for an empty string epilogue,
+ # which means a single newline.
+ if epilogue:
+ firstline = epilogue[0]
+ bolmo = NLCRE_bol.match(firstline)
+ if bolmo:
+ epilogue[0] = firstline[len(bolmo.group(0)):]
+ self._cur.epilogue = EMPTYSTRING.join(epilogue)
+ return
+ # Otherwise, it's some non-multipart type, so the entire rest of the
+ # file contents becomes the payload.
+ lines = []
+ for line in self._input:
+ if line is NeedMoreData:
+ yield NeedMoreData
+ continue
+ lines.append(line)
+ self._cur.set_payload(EMPTYSTRING.join(lines))
+
+ def _parse_headers(self, lines):
+ # Passed a list of lines that make up the headers for the current msg
+ lastheader = ''
+ lastvalue = []
+ for lineno, line in enumerate(lines):
+ # Check for continuation
+ if line[0] in ' \t':
+ if not lastheader:
+ # The first line of the headers was a continuation. This
+ # is illegal, so let's note the defect, store the illegal
+ # line, and ignore it for purposes of headers.
+ defect = errors.FirstHeaderLineIsContinuationDefect(line)
+ self._cur.defects.append(defect)
+ continue
+ lastvalue.append(line)
+ continue
+ if lastheader:
+ # XXX reconsider the joining of folded lines
+ lhdr = EMPTYSTRING.join(lastvalue)[:-1].rstrip('\r\n')
+ self._cur[lastheader] = lhdr
+ lastheader, lastvalue = '', []
+ # Check for envelope header, i.e. unix-from
+ if line.startswith('From '):
+ if lineno == 0:
+ # Strip off the trailing newline
+ mo = NLCRE_eol.search(line)
+ if mo:
+ line = line[:-len(mo.group(0))]
+ self._cur.set_unixfrom(line)
+ continue
+ elif lineno == len(lines) - 1:
+ # Something looking like a unix-from at the end - it's
+ # probably the first line of the body, so push back the
+ # line and stop.
+ self._input.unreadline(line)
+ return
+ else:
+ # Weirdly placed unix-from line. Note this as a defect
+ # and ignore it.
+ 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)
+ self._cur.defects.append(defect)
+ continue
+ lastheader = line[:i]
+ lastvalue = [line[i+1:].lstrip()]
+ # Done with all the lines, so handle the last header.
+ if lastheader:
+ # XXX reconsider the joining of folded lines
+ self._cur[lastheader] = EMPTYSTRING.join(lastvalue).rstrip('\r\n')