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Diffstat (limited to 'lib/python2.7/email/feedparser.py')
| -rw-r--r-- | lib/python2.7/email/feedparser.py | 484 |
1 files changed, 484 insertions, 0 deletions
diff --git a/lib/python2.7/email/feedparser.py b/lib/python2.7/email/feedparser.py new file mode 100644 index 0000000..15db26d --- /dev/null +++ b/lib/python2.7/email/feedparser.py @@ -0,0 +1,484 @@ +# 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 raise 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)\Z') +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() + #GAN 29Mar09 bugs 1555570, 1721862 Confusion at 8K boundary ending with \r: + # is there a \n to follow later? + if not self._partial and parts and parts[-1].endswith('\r'): + self._partial = parts.pop(-2)+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 raise 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') |