Application: gvSIG desktop

"""RFC-822 message manipulation class.

XXX This is only a very rough sketch of a full RFC-822 parser;

in particular the tokenizing of addresses does not adhere to all the

quoting rules.

Directions for use:

To create a Message object: first open a file, e.g.:

  fp = open(file, 'r')

You can use any other legal way of getting an open file object, e.g. use

sys.stdin or call os.popen().

Then pass the open file object to the Message() constructor:

  m = Message(fp)

This class can work with any input object that supports a readline

method.  If the input object has seek and tell capability, the

rewindbody method will work; also illegal lines will be pushed back

onto the input stream.  If the input object lacks seek but has an

`unread' method that can push back a line of input, Message will use

that to push back illegal lines.  Thus this class can be used to parse

messages coming from a buffered stream.

The optional `seekable' argument is provided as a workaround for

certain stdio libraries in which tell() discards buffered data before

discovering that the lseek() system call doesn't work.  For maximum

portability, you should set the seekable argument to zero to prevent

that initial \code{tell} when passing in an unseekable object such as

a a file object created from a socket object.  If it is 1 on entry --

which it is by default -- the tell() method of the open file object is

called once; if this raises an exception, seekable is reset to 0.  For

other nonzero values of seekable, this test is not made.

To get the text of a particular header there are several methods:

  str = m.getheader(name)

  str = m.getrawheader(name)

where name is the name of the header, e.g. 'Subject'.

The difference is that getheader() strips the leading and trailing

whitespace, while getrawheader() doesn't.  Both functions retain

embedded whitespace (including newlines) exactly as they are

specified in the header, and leave the case of the text unchanged.

For addresses and address lists there are functions

  realname, mailaddress = m.getaddr(name) and

  list = m.getaddrlist(name)

where the latter returns a list of (realname, mailaddr) tuples.

There is also a method

  time = m.getdate(name)

which parses a Date-like field and returns a time-compatible tuple,

i.e. a tuple such as returned by time.localtime() or accepted by

time.mktime().

See the class definition for lower level access methods.

There are also some utility functions here.

"""

# Cleanup and extensions by Eric S. Raymond <esr@thyrsus.com>

import time

__all__ = ["Message","AddressList","parsedate","parsedate_tz","mktime_tz"]

_blanklines = ('\r\n', '\n')            # Optimization for islast()

class Message:

    """Represents a single RFC-822-compliant message."""

    def __init__(self, fp, seekable = 1):

        """Initialize the class instance and read the headers."""

        if seekable == 1:

            # Exercise tell() to make sure it works

            # (and then assume seek() works, too)

            try:

                fp.tell()

            except:

                seekable = 0

            else:

                seekable = 1

        self.fp = fp

        self.seekable = seekable

        self.startofheaders = None

        self.startofbody = None

        #

        if self.seekable:

            try:

                self.startofheaders = self.fp.tell()

            except IOError:

                self.seekable = 0

        #

        self.readheaders()

        #

        if self.seekable:

            try:

                self.startofbody = self.fp.tell()

            except IOError:

                self.seekable = 0

    def rewindbody(self):

        """Rewind the file to the start of the body (if seekable)."""

        if not self.seekable:

            raise IOError, "unseekable file"

        self.fp.seek(self.startofbody)

    def readheaders(self):

        """Read header lines.

        Read header lines up to the entirely blank line that

        terminates them.  The (normally blank) line that ends the

        headers is skipped, but not included in the returned list.

        If a non-header line ends the headers, (which is an error),

        an attempt is made to backspace over it; it is never

        included in the returned list.

        The variable self.status is set to the empty string if all

        went well, otherwise it is an error message.

        The variable self.headers is a completely uninterpreted list

        of lines contained in the header (so printing them will

        reproduce the header exactly as it appears in the file).

        """

        self.dict = {}

        self.unixfrom = ''

        self.headers = list = []

        self.status = ''

        headerseen = ""

        firstline = 1

        startofline = unread = tell = None

        if hasattr(self.fp, 'unread'):

            unread = self.fp.unread

        elif self.seekable:

            tell = self.fp.tell

        while 1:

            if tell:

                try:

                    startofline = tell()

                except IOError:

                    startofline = tell = None

                    self.seekable = 0

            line = self.fp.readline()

            if not line:

                self.status = 'EOF in headers'

                break

            # Skip unix From name time lines

            if firstline and line.startswith('From '):

                self.unixfrom = self.unixfrom + line

                continue

            firstline = 0

            if headerseen and line[0] in ' \t':

                # It's a continuation line.

                list.append(line)

                x = (self.dict[headerseen] + "\n " + line.strip())

                self.dict[headerseen] = x.strip()

                continue

            elif self.iscomment(line):

                # It's a comment.  Ignore it.

                continue

            elif self.islast(line):

                # Note! No pushback here!  The delimiter line gets eaten.

                break

            headerseen = self.isheader(line)

            if headerseen:

                # It's a legal header line, save it.

                list.append(line)

                self.dict[headerseen] = line[len(headerseen)+1:].strip()

                continue

            else:

                # It's not a header line; throw it back and stop here.

                if not self.dict:

                    self.status = 'No headers'

                else:

                    self.status = 'Non-header line where header expected'

                # Try to undo the read.

                if unread:

                    unread(line)

                elif tell:

                    self.fp.seek(startofline)

                else:

                    self.status = self.status + '; bad seek'

                break

    def isheader(self, line):

        """Determine whether a given line is a legal header.

        This method should return the header name, suitably canonicalized.

        You may override this method in order to use Message parsing

        on tagged data in RFC822-like formats with special header formats.

        """

        i = line.find(':')

        if i > 0:

            return line[:i].lower()

        else:

            return None

    def islast(self, line):

        """Determine whether a line is a legal end of RFC-822 headers.

        You may override this method if your application wants

        to bend the rules, e.g. to strip trailing whitespace,

        or to recognize MH template separators ('--------').

        For convenience (e.g. for code reading from sockets) a

        line consisting of \r\n also matches.

        """

        return line in _blanklines

    def iscomment(self, line):

        """Determine whether a line should be skipped entirely.

        You may override this method in order to use Message parsing

        on tagged data in RFC822-like formats that support embedded

        comments or free-text data.

        """

        return None

    def getallmatchingheaders(self, name):

        """Find all header lines matching a given header name.

        Look through the list of headers and find all lines

        matching a given header name (and their continuation

        lines).  A list of the lines is returned, without

        interpretation.  If the header does not occur, an

        empty list is returned.  If the header occurs multiple

        times, all occurrences are returned.  Case is not

        important in the header name.

        """

        name = name.lower() + ':'

        n = len(name)

        list = []

        hit = 0

        for line in self.headers:

            if line[:n].lower() == name:

                hit = 1

            elif not line[:1].isspace():

                hit = 0

            if hit:

                list.append(line)

        return list

    def getfirstmatchingheader(self, name):

        """Get the first header line matching name.

        This is similar to getallmatchingheaders, but it returns

        only the first matching header (and its continuation

        lines).

        """

        name = name.lower() + ':'

        n = len(name)

        list = []

        hit = 0

        for line in self.headers:

            if hit:

                if not line[:1].isspace():

                    break

            elif line[:n].lower() == name:

                hit = 1

            if hit:

                list.append(line)

        return list

    def getrawheader(self, name):

        """A higher-level interface to getfirstmatchingheader().

        Return a string containing the literal text of the

        header but with the keyword stripped.  All leading,

        trailing and embedded whitespace is kept in the

        string, however.

        Return None if the header does not occur.

        """

        list = self.getfirstmatchingheader(name)

        if not list:

            return None

        list[0] = list[0][len(name) + 1:]

        return ''.join(list)

    def getheader(self, name, default=None):

        """Get the header value for a name.

        This is the normal interface: it returns a stripped

        version of the header value for a given header name,

        or None if it doesn't exist.  This uses the dictionary

        version which finds the *last* such header.

        """

        try:

            return self.dict[name.lower()]

        except KeyError:

            return default

    get = getheader

    def getheaders(self, name):

        """Get all values for a header.

        This returns a list of values for headers given more than once;

        each value in the result list is stripped in the same way as the

        result of getheader().  If the header is not given, return an

        empty list.

        """

        result = []

        current = ''

        have_header = 0

        for s in self.getallmatchingheaders(name):

            if s[0].isspace():

                if current:

                    current = "%s\n %s" % (current, s.strip())

                else:

                    current = s.strip()

            else:

                if have_header:

                    result.append(current)

                current = s[s.find(":") + 1:].strip()

                have_header = 1

        if have_header:

            result.append(current)

        return result

    def getaddr(self, name):

        """Get a single address from a header, as a tuple.

        An example return value:

        ('Guido van Rossum', 'guido@cwi.nl')

        """

        # New, by Ben Escoto

        alist = self.getaddrlist(name)

        if alist:

            return alist[0]

        else:

            return (None, None)

    def getaddrlist(self, name):

        """Get a list of addresses from a header.

        Retrieves a list of addresses from a header, where each address is a

        tuple as returned by getaddr().  Scans all named headers, so it works

        properly with multiple To: or Cc: headers for example.

        """

        raw = []

        for h in self.getallmatchingheaders(name):

            if h[0] in ' \t':

                raw.append(h)

            else:

                if raw:

                    raw.append(', ')

                i = h.find(':')

                if i > 0:

                    addr = h[i+1:]

                raw.append(addr)

        alladdrs = ''.join(raw)

        a = AddrlistClass(alladdrs)

        return a.getaddrlist()

    def getdate(self, name):

        """Retrieve a date field from a header.

        Retrieves a date field from the named header, returning

        a tuple compatible with time.mktime().

        """

        try:

            data = self[name]

        except KeyError:

            return None

        return parsedate(data)

    def getdate_tz(self, name):

        """Retrieve a date field from a header as a 10-tuple.

        The first 9 elements make up a tuple compatible with

        time.mktime(), and the 10th is the offset of the poster's

        time zone from GMT/UTC.

        """

        try:

            data = self[name]

        except KeyError:

            return None

        return parsedate_tz(data)

    # Access as a dictionary (only finds *last* header of each type):

    def __len__(self):

        """Get the number of headers in a message."""

        return len(self.dict)

    def __getitem__(self, name):

        """Get a specific header, as from a dictionary."""

        return self.dict[name.lower()]

    def __setitem__(self, name, value):

        """Set the value of a header.

        Note: This is not a perfect inversion of __getitem__, because

        any changed headers get stuck at the end of the raw-headers list

        rather than where the altered header was.

        """

        del self[name] # Won't fail if it doesn't exist

        self.dict[name.lower()] = value

        text = name + ": " + value

        lines = text.split("\n")

        for line in lines:

            self.headers.append(line + "\n")

    def __delitem__(self, name):

        """Delete all occurrences of a specific header, if it is present."""

        name = name.lower()

        if not self.dict.has_key(name):

            return

        del self.dict[name]

        name = name + ':'

        n = len(name)

        list = []

        hit = 0

        for i in range(len(self.headers)):

            line = self.headers[i]

            if line[:n].lower() == name:

                hit = 1

            elif not line[:1].isspace():

                hit = 0

            if hit:

                list.append(i)

        list.reverse()

        for i in list:

            del self.headers[i]

    def has_key(self, name):

        """Determine whether a message contains the named header."""

        return self.dict.has_key(name.lower())

    def keys(self):

        """Get all of a message's header field names."""

        return self.dict.keys()

    def values(self):

        """Get all of a message's header field values."""

        return self.dict.values()

    def items(self):

        """Get all of a message's headers.

        Returns a list of name, value tuples.

        """

        return self.dict.items()

    def __str__(self):

        str = ''

        for hdr in self.headers:

            str = str + hdr

        return str

# Utility functions

# -----------------

# XXX Should fix unquote() and quote() to be really conformant.

# XXX The inverses of the parse functions may also be useful.

def unquote(str):

    """Remove quotes from a string."""

    if len(str) > 1:

        if str[0] == '"' and str[-1:] == '"':

            return str[1:-1]

        if str[0] == '<' and str[-1:] == '>':

            return str[1:-1]

    return str

def quote(str):

    """Add quotes around a string."""

    return str.replace('\\', '\\\\').replace('"', '\\"')

def parseaddr(address):

    """Parse an address into a (realname, mailaddr) tuple."""

    a = AddrlistClass(address)

    list = a.getaddrlist()

    if not list:

        return (None, None)

    else:

        return list[0]

class AddrlistClass:

    """Address parser class by Ben Escoto.

    To understand what this class does, it helps to have a copy of

    RFC-822 in front of you.

    Note: this class interface is deprecated and may be removed in the future.

    Use rfc822.AddressList instead.

    """

    def __init__(self, field):

        """Initialize a new instance.

        `field' is an unparsed address header field, containing

        one or more addresses.

        """

        self.specials = '()<>@,:;.\"[]'

        self.pos = 0

        self.LWS = ' \t'

        self.CR = '\r\n'

        self.atomends = self.specials + self.LWS + self.CR

        self.field = field

        self.commentlist = []

    def gotonext(self):

        """Parse up to the start of the next address."""

        while self.pos < len(self.field):

            if self.field[self.pos] in self.LWS + '\n\r':

                self.pos = self.pos + 1

            elif self.field[self.pos] == '(':

                self.commentlist.append(self.getcomment())

            else: break

    def getaddrlist(self):

        """Parse all addresses.

        Returns a list containing all of the addresses.

        """

        ad = self.getaddress()

        if ad:

            return ad + self.getaddrlist()

        else: return []

    def getaddress(self):

        """Parse the next address."""

        self.commentlist = []

        self.gotonext()

        oldpos = self.pos

        oldcl = self.commentlist

        plist = self.getphraselist()

        self.gotonext()

        returnlist = []

        if self.pos >= len(self.field):

            # Bad email address technically, no domain.

            if plist:

                returnlist = [(' '.join(self.commentlist), plist[0])]

        elif self.field[self.pos] in '.@':

            # email address is just an addrspec

            # this isn't very efficient since we start over

            self.pos = oldpos

            self.commentlist = oldcl

            addrspec = self.getaddrspec()

            returnlist = [(' '.join(self.commentlist), addrspec)]

        elif self.field[self.pos] == ':':

            # address is a group

            returnlist = []

            fieldlen = len(self.field)

            self.pos = self.pos + 1

            while self.pos < len(self.field):

                self.gotonext()

                if self.pos < fieldlen and self.field[self.pos] == ';':

                    self.pos = self.pos + 1

                    break

                returnlist = returnlist + self.getaddress()

        elif self.field[self.pos] == '<':

            # Address is a phrase then a route addr

            routeaddr = self.getrouteaddr()

            if self.commentlist:

                returnlist = [(' '.join(plist) + ' (' + \

                         ' '.join(self.commentlist) + ')', routeaddr)]

            else: returnlist = [(' '.join(plist), routeaddr)]

        else:

            if plist:

                returnlist = [(' '.join(self.commentlist), plist[0])]

            elif self.field[self.pos] in self.specials:

                self.pos = self.pos + 1

        self.gotonext()

        if self.pos < len(self.field) and self.field[self.pos] == ',':

            self.pos = self.pos + 1

        return returnlist

    def getrouteaddr(self):

        """Parse a route address (Return-path value).

        This method just skips all the route stuff and returns the addrspec.

        """

        if self.field[self.pos] != '<':

            return

        expectroute = 0

        self.pos = self.pos + 1

        self.gotonext()

        adlist = None

        while self.pos < len(self.field):

            if expectroute:

                self.getdomain()

                expectroute = 0

            elif self.field[self.pos] == '>':

                self.pos = self.pos + 1

                break

            elif self.field[self.pos] == '@':

                self.pos = self.pos + 1

                expectroute = 1

            elif self.field[self.pos] == ':':

                self.pos = self.pos + 1

                expectaddrspec = 1

            else:

                adlist = self.getaddrspec()

                self.pos = self.pos + 1

                break

            self.gotonext()

        return adlist

    def getaddrspec(self):

        """Parse an RFC-822 addr-spec."""

        aslist = []

        self.gotonext()

        while self.pos < len(self.field):

            if self.field[self.pos] == '.':

                aslist.append('.')

                self.pos = self.pos + 1

            elif self.field[self.pos] == '"':

                aslist.append('"%s"' % self.getquote())

            elif self.field[self.pos] in self.atomends:

                break

            else: aslist.append(self.getatom())

            self.gotonext()

        if self.pos >= len(self.field) or self.field[self.pos] != '@':

            return ''.join(aslist)

        aslist.append('@')

        self.pos = self.pos + 1

        self.gotonext()

        return ''.join(aslist) + self.getdomain()

    def getdomain(self):

        """Get the complete domain name from an address."""

        sdlist = []

        while self.pos < len(self.field):

            if self.field[self.pos] in self.LWS:

                self.pos = self.pos + 1

            elif self.field[self.pos] == '(':

                self.commentlist.append(self.getcomment())

            elif self.field[self.pos] == '[':

                sdlist.append(self.getdomainliteral())

            elif self.field[self.pos] == '.':

                self.pos = self.pos + 1

                sdlist.append('.')

            elif self.field[self.pos] in self.atomends:

                break

            else: sdlist.append(self.getatom())

        return ''.join(sdlist)

    def getdelimited(self, beginchar, endchars, allowcomments = 1):

        """Parse a header fragment delimited by special characters.

        `beginchar' is the start character for the fragment.

        If self is not looking at an instance of `beginchar' then

        getdelimited returns the empty string.

        `endchars' is a sequence of allowable end-delimiting characters.

        Parsing stops when one of these is encountered.

        If `allowcomments' is non-zero, embedded RFC-822 comments

        are allowed within the parsed fragment.

        """

        if self.field[self.pos] != beginchar:

            return ''

        slist = ['']

        quote = 0

        self.pos = self.pos + 1

        while self.pos < len(self.field):

            if quote == 1:

                slist.append(self.field[self.pos])

                quote = 0

            elif self.field[self.pos] in endchars:

                self.pos = self.pos + 1

                break

            elif allowcomments and self.field[self.pos] == '(':

                slist.append(self.getcomment())

            elif self.field[self.pos] == '\\':

                quote = 1

            else:

                slist.append(self.field[self.pos])

            self.pos = self.pos + 1

        return ''.join(slist)

    def getquote(self):

        """Get a quote-delimited fragment from self's field."""

        return self.getdelimited('"', '"\r', 0)

    def getcomment(self):

        """Get a parenthesis-delimited fragment from self's field."""

        return self.getdelimited('(', ')\r', 1)

    def getdomainliteral(self):

        """Parse an RFC-822 domain-literal."""

        return '[%s]' % self.getdelimited('[', ']\r', 0)

    def getatom(self):

        """Parse an RFC-822 atom."""

        atomlist = ['']

        while self.pos < len(self.field):

            if self.field[self.pos] in self.atomends:

                break

            else: atomlist.append(self.field[self.pos])

            self.pos = self.pos + 1

        return ''.join(atomlist)

    def getphraselist(self):

        """Parse a sequence of RFC-822 phrases.

        A phrase is a sequence of words, which are in turn either

        RFC-822 atoms or quoted-strings.  Phrases are canonicalized

        by squeezing all runs of continuous whitespace into one space.

        """

        plist = []

        while self.pos < len(self.field):

            if self.field[self.pos] in self.LWS:

                self.pos = self.pos + 1

            elif self.field[self.pos] == '"':

                plist.append(self.getquote())

            elif self.field[self.pos] == '(':

                self.commentlist.append(self.getcomment())

            elif self.field[self.pos] in self.atomends:

                break

            else: plist.append(self.getatom())

        return plist

class AddressList(AddrlistClass):

    """An AddressList encapsulates a list of parsed RFC822 addresses."""

    def __init__(self, field):

        AddrlistClass.__init__(self, field)

        if field:

            self.addresslist = self.getaddrlist()

        else:

            self.addresslist = []

    def __len__(self):

        return len(self.addresslist)

    def __str__(self):

        return ", ".join(map(dump_address_pair, self.addresslist))

    def __add__(self, other):

        # Set union

        newaddr = AddressList(None)

        newaddr.addresslist = self.addresslist[:]

        for x in other.addresslist:

            if not x in self.addresslist:

                newaddr.addresslist.append(x)

        return newaddr

    def __iadd__(self, other):

        # Set union, in-place

        for x in other.addresslist:

            if not x in self.addresslist:

                self.addresslist.append(x)

        return self

    def __sub__(self, other):

        # Set difference

        newaddr = AddressList(None)

        for x in self.addresslist:

            if not x in other.addresslist:

                newaddr.addresslist.append(x)

        return newaddr

    def __isub__(self, other):

        # Set difference, in-place

        for x in other.addresslist:

            if x in self.addresslist:

                self.addresslist.remove(x)

        return self

    def __getitem__(self, index):

        # Make indexing, slices, and 'in' work

        return self.addresslist[index]

def dump_address_pair(pair):

    """Dump a (name, address) pair in a canonicalized form."""

    if pair[0]:

        return '"' + pair[0] + '" <' + pair[1] + '>'

    else:

        return pair[1]

# Parse a date field

_monthnames = ['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul',

               'aug', 'sep', 'oct', 'nov', 'dec',

               'january', 'february', 'march', 'april', 'may', 'june', 'july',

               'august', 'september', 'october', 'november', 'december']

_daynames = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']

# The timezone table does not include the military time zones defined

# in RFC822, other than Z.  According to RFC1123, the description in

# RFC822 gets the signs wrong, so we can't rely on any such time

# zones.  RFC1123 recommends that numeric timezone indicators be used

# instead of timezone names.

_timezones = {'UT':0, 'UTC':0, 'GMT':0, 'Z':0,

              'AST': -400, 'ADT': -300,  # Atlantic (used in Canada)

              'EST': -500, 'EDT': -400,  # Eastern

              'CST': -600, 'CDT': -500,  # Central

              'MST': -700, 'MDT': -600,  # Mountain

              'PST': -800, 'PDT': -700   # Pacific

              }

def parsedate_tz(data):

    """Convert a date string to a time tuple.

    Accounts for military timezones.

    """

    data = data.split()

    if data[0][-1] in (',', '.') or data[0].lower() in _daynames:

        # There's a dayname here. Skip it

        del data[0]

    if len(data) == 3: # RFC 850 date, deprecated

        stuff = data[0].split('-')

        if len(stuff) == 3:

            data = stuff + data[1:]

    if len(data) == 4:

        s = data[3]

        i = s.find('+')

        if i > 0:

            data[3:] = [s[:i], s[i+1:]]

        else:

            data.append('') # Dummy tz

    if len(data) < 5:

        return None

    data = data[:5]

    [dd, mm, yy, tm, tz] = data

    mm = mm.lower()

    if not mm in _monthnames:

        dd, mm = mm, dd.lower()

        if not mm in _monthnames:

            return None

    mm = _monthnames.index(mm)+1

    if mm > 12: mm = mm - 12

    if dd[-1] == ',':

        dd = dd[:-1]

    i = yy.find(':')

    if i > 0:

        yy, tm = tm, yy

    if yy[-1] == ',':

        yy = yy[:-1]

    if not yy[0].isdigit():

        yy, tz = tz, yy

    if tm[-1] == ',':

        tm = tm[:-1]

    tm = tm.split(':')

    if len(tm) == 2:

        [thh, tmm] = tm

        tss = '0'

    elif len(tm) == 3:

        [thh, tmm, tss] = tm

    else:

        return None

    try:

        yy = int(yy)

        dd = int(dd)

        thh = int(thh)

        tmm = int(tmm)

        tss = int(tss)

    except ValueError:

        return None

    tzoffset = None

    tz = tz.upper()

    if _timezones.has_key(tz):

        tzoffset = _timezones[tz]

    else:

        try:

            tzoffset = int(tz)

        except ValueError:

            pass

    # Convert a timezone offset into seconds ; -0500 -> -18000

    if tzoffset:

        if tzoffset < 0:

            tzsign = -1

            tzoffset = -tzoffset

        else:

            tzsign = 1

        tzoffset = tzsign * ( (tzoffset/100)*3600 + (tzoffset % 100)*60)

    tuple = (yy, mm, dd, thh, tmm, tss, 0, 0, 0, tzoffset)

    return tuple

def parsedate(data):

    """Convert a time string to a time tuple."""

    t = parsedate_tz(data)

    if type(t) == type( () ):

        return t[:9]

    else: return t

def mktime_tz(data):

    """Turn a 10-tuple as returned by parsedate_tz() into a UTC timestamp."""

    if data[9] is None:

        # No zone info, so localtime is better assumption than GMT

        return time.mktime(data[:8] + (-1,))

    else:

        t = time.mktime(data[:8] + (0,))

        return t - data[9] - time.timezone

def formatdate(timeval=None):

    """Returns time format preferred for Internet standards.

    Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123

    """

    if timeval is None:

        timeval = time.time()

    return "%s" % time.strftime('%a, %d %b %Y %H:%M:%S GMT',

                                time.gmtime(timeval))

# When used as script, run a small test program.

# The first command line argument must be a filename containing one

# message in RFC-822 format.

if __name__ == '__main__':

    import sys, os

    file = os.path.join(os.environ['HOME'], 'Mail/inbox/1')

    if sys.argv[1:]: file = sys.argv[1]

    f = open(file, 'r')

    m = Message(f)

    print 'From:', m.getaddr('from')

    print 'To:', m.getaddrlist('to')

    print 'Subject:', m.getheader('subject')

    print 'Date:', m.getheader('date')

    date = m.getdate_tz('date')

    tz = date[-1]

    date = time.localtime(mktime_tz(date))

    if date:

        print 'ParsedDate:', time.asctime(date),

        hhmmss = tz

        hhmm, ss = divmod(hhmmss, 60)

        hh, mm = divmod(hhmm, 60)

        print "%+03d%02d" % (hh, mm),

        if ss: print ".%02d" % ss,

        print

    else:

        print 'ParsedDate:', None

    m.rewindbody()

    n = 0

    while f.readline():

        n = n + 1

    print 'Lines:', n

    print '-'*70

    print 'len =', len(m)

    if m.has_key('Date'): print 'Date =', m['Date']

    if m.has_key('X-Nonsense'): pass

    print 'keys =', m.keys()

    print 'values =', m.values()

    print 'items =', m.items()