Merge email package 4.0 from the sandbox, including documentation, test cases,

and NEWS updates.

1 files changed, 480 insertions, 0 deletions

diff --git a/Lib/email/feedparser.py b/Lib/email/feedparser.py
new file mode 100644
index 0000000..afb02b3
--- /dev/null
+++ b/Lib/email/feedparser.py
@@ -0,0 +1,480 @@
+# 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')