"""RFC 2822 message manipulation.
Note: 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.
Note: RFC 2822 is a long awaited update to RFC 822. This module should
conform to RFC 2822, and is thus mis-named (it's not worth renaming it). Some
effort at RFC 2822 updates have been made, but a thorough audit has not been
performed. Consider any RFC 2822 non-conformance to be a bug.
RFC 2822: http://www.faqs.org/rfcs/rfc2822.html
RFC 822 : http://www.faqs.org/rfcs/rfc822.html (obsolete)
To create a Message object: first open a file, e.g.:
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()
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 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.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
For addresses and address lists there are functions
realname, mailaddress = m.getaddr(name)
list = m.getaddrlist(name)
where the latter returns a list of (realname, mailaddr) tuples.
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
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>
from warnings import warnpy3k
warnpy3k("in 3.x, rfc822 has been removed in favor of the email package",
__all__ = ["Message","AddressList","parsedate","parsedate_tz","mktime_tz"]
_blanklines = ('\r\n', '\n') # Optimization for islast()
"""Represents a single RFC 2822-compliant message."""
def __init__(self, fp, seekable = 1):
"""Initialize the class instance and read the headers."""
# Exercise tell() to make sure it works
# (and then assume seek() works, too)
except (AttributeError, IOError):
self.startofheaders = None
self.startofheaders = self.fp.tell()
self.startofbody = self.fp.tell()
"""Rewind the file to the start of the body (if seekable)."""
raise IOError, "unseekable file"
self.fp.seek(self.startofbody)
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
startofline = unread = tell = None
if hasattr(self.fp, 'unread'):
startofline = tell = None
line = self.fp.readline()
self.status = 'EOF in headers'
# Skip unix From name time lines
if firstline and line.startswith('From '):
self.unixfrom = self.unixfrom + line
if headerseen and line[0] in ' \t':
# It's a continuation line.
x = (self.dict[headerseen] + "\n " + line.strip())
self.dict[headerseen] = x.strip()
elif self.iscomment(line):
# It's a comment. Ignore it.
# Note! No pushback here! The delimiter line gets eaten.
headerseen = self.isheader(line)
# It's a legal header line, save it.
self.dict[headerseen] = line[len(headerseen)+1:].strip()
elif headerseen is not None:
# An empty header name. These aren't allowed in HTTP, but it's
# probably a benign mistake. Don't add the header, just keep
# It's not a header line; throw it back and stop here.
self.status = 'No headers'
self.status = 'Non-header line where header expected'
self.fp.seek(startofline)
self.status = self.status + '; bad seek'
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 RFC 2822-like formats with special header formats.
"""Determine whether a line is a legal end of RFC 2822 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 RFC 2822-like formats that support embedded comments or
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() + ':'
for line in self.headers:
if line[:n].lower() == name:
elif not line[:1].isspace():
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() + ':'
for line in self.headers:
if not line[:1].isspace():
elif line[:n].lower() == name:
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
lst = self.getfirstmatchingheader(name)
lst[0] = lst[0][len(name) + 1:]
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.
return self.dict.get(name.lower(), default)
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.
for s in self.getallmatchingheaders(name):
current = "%s\n %s" % (current, s.strip())
current = s[s.find(":") + 1:].strip()
"""Get a single address from a header, as a tuple.
('Guido van Rossum', 'guido@cwi.nl')
alist = self.getaddrlist(name)
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.
for h in self.getallmatchingheaders(name):
a = AddressList(alladdrs)
"""Retrieve a date field from a header.
Retrieves a date field from the named header, returning a tuple
compatible with time.mktime().
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.
return parsedate_tz(data)
# Access as a dictionary (only finds *last* header of each type):
"""Get the number of headers in a message."""
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
for line in text.split("\n"):
self.headers.append(line + "\n")
def __delitem__(self, name):
"""Delete all occurrences of a specific header, if it is present."""
if not name in self.dict:
for i in range(len(self.headers)):
if line[:n].lower() == name:
elif not line[:1].isspace():
def setdefault(self, name, default=""):
if lowername in self.dict:
return self.dict[lowername]
text = name + ": " + default
for line in text.split("\n"):
self.headers.append(line + "\n")
self.dict[lowername] = default
"""Determine whether a message contains the named header."""
return name.lower() in self.dict
def __contains__(self, name):
"""Determine whether a message contains the named header."""
return name.lower() in self.dict
"""Get all of a message's header field names."""
"""Get all of a message's header field values."""
return self.dict.values()
"""Get all of a message's headers.
Returns a list of name, value tuples.
return ''.join(self.headers)
# XXX Should fix unquote() and quote() to be really conformant.
# XXX The inverses of the parse functions may also be useful.
"""Remove quotes from a string."""
if s.startswith('"') and s.endswith('"'):
return s[1:-1].replace('\\\\', '\\').replace('\\"', '"')
if s.startswith('<') and s.endswith('>'):
"""Add quotes around a string."""
return s.replace('\\', '\\\\').replace('"', '\\"')
"""Parse an address into a (realname, mailaddr) tuple."""
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
