cpython/Lib/rfc822.py

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# 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')
# (or 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)
#
# 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.
import regex
import string
import time
class Message:
# Initialize the class instance and read the headers.
def __init__(self, fp):
self.fp = fp
#
try:
self.startofheaders = self.fp.tell()
except IOError:
self.startofheaders = None
#
self.readheaders()
#
try:
self.startofbody = self.fp.tell()
except IOError:
self.startofbody = None
# Rewind the file to the start of the body (if seekable).
def rewindbody(self):
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 file).
def readheaders(self):
self.headers = list = []
self.status = ''
headerseen = 0
while 1:
line = self.fp.readline()
if not line:
self.status = 'EOF in headers'
break
if self.islast(line):
break
elif headerseen and line[0] in ' \t':
# It's a continuation line.
list.append(line)
elif regex.match('^[!-9;-~]+:', line) >= 0:
# It's a header line.
list.append(line)
headerseen = 1
else:
# It's not a header line; stop here.
if not headerseen:
self.status = 'No headers'
else:
self.status = 'Bad header'
# Try to undo the read.
try:
self.fp.seek(-len(line), 1)
except IOError:
self.status = \
self.status + '; bad seek'
break
# Method to 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 recognise MH template separators
# ('--------'). For convenience (e.g. for code reading from
# sockets) a line consisting of \r\n also matches.
def islast(self, line):
return line == '\n' or line == '\r\n'
# 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.
def getallmatchingheaders(self, name):
name = string.lower(name) + ':'
n = len(name)
list = []
hit = 0
for line in self.headers:
if string.lower(line[:n]) == name:
hit = 1
elif line[:1] not in string.whitespace:
hit = 0
if hit:
list.append(line)
return list
# Similar, but return only the first matching header (and its
# continuation lines).
def getfirstmatchingheader(self, name):
name = string.lower(name) + ':'
n = len(name)
list = []
hit = 0
for line in self.headers:
if hit:
if line[:1] not in string.whitespace:
break
elif string.lower(line[:n]) == name:
hit = 1
if hit:
list.append(line)
return list
# 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.
def getrawheader(self, name):
list = self.getfirstmatchingheader(name)
if not list:
return None
list[0] = list[0][len(name) + 1:]
return string.joinfields(list, '')
# Going one step further: also strip leading and trailing
# whitespace.
def getheader(self, name):
text = self.getrawheader(name)
if text == None:
return None
return string.strip(text)
# Retrieve a single address from a header as a tuple, e.g.
# ('Guido van Rossum', 'guido@cwi.nl').
def getaddr(self, name):
data = self.getheader(name)
if not data:
return None, None
return parseaddr(data)
# Retrieve a list of addresses from a header, where each
# address is a tuple as returned by getaddr().
def getaddrlist(self, name):
# XXX This function is not really correct. The split
# on ',' might fail in the case of commas within
# quoted strings.
data = self.getheader(name)
if not data:
return []
data = string.splitfields(data, ',')
for i in range(len(data)):
data[i] = parseaddr(data[i])
return data
# Retrieve a date field from a header as a tuple compatible
# with time.mktime().
def getdate(self, name):
data = self.getheader(name)
if not data:
return None
return parsedate(data)
# Access as a dictionary (only finds first header of each type):
def __len__(self):
types = {}
for line in self.headers:
if line[0] in string.whitespace: continue
i = string.find(line, ':')
if i > 0:
name = string.lower(line[:i])
types[name] = None
return len(types)
def __getitem__(self, name):
value = self.getheader(name)
if value is None: raise KeyError, name
return value
def has_key(self, name):
value = self.getheader(name)
return value is not None
def keys(self):
types = {}
for line in self.headers:
if line[0] in string.whitespace: continue
i = string.find(line, ':')
if i > 0:
name = line[:i]
key = string.lower(name)
types[key] = name
return types.values()
def values(self):
values = []
for name in self.keys():
values.append(self[name])
return values
def items(self):
items = []
for name in self.keys():
items.append(name, self[name])
return items
# Utility functions
# -----------------
# XXX Should fix these to be really conformant.
# XXX The inverses of the parse functions may also be useful.
# Remove quotes from a string.
def unquote(str):
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
# Parse an address into (name, address) tuple
def parseaddr(address):
# This is probably not perfect
address = string.strip(address)
# Case 1: part of the address is in <xx@xx> form.
pos = regex.search('<.*>', address)
if pos >= 0:
name = address[:pos]
address = address[pos:]
length = regex.match('<.*>', address)
name = name + address[length:]
address = address[:length]
else:
# Case 2: part of the address is in (comment) form
pos = regex.search('(.*)', address)
if pos >= 0:
name = address[pos:]
address = address[:pos]
length = regex.match('(.*)', name)
address = address + name[length:]
name = name[:length]
else:
# Case 3: neither. Only an address
name = ''
name = string.strip(name)
address = string.strip(address)
if address and address[0] == '<' and address[-1] == '>':
address = address[1:-1]
if name and name[0] == '(' and name[-1] == ')':
name = name[1:-1]
return name, address
# Parse a date field
_monthnames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul',
'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
def parsedate(data):
# XXX This still mostly ignores timezone matters at the moment...
data = string.split(data)
if data[0][-1] == ',':
# There's a dayname here. Skip it
del data[0]
if len(data) == 4:
s = data[3]
i = string.find(s, '+')
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
if not mm in _monthnames:
return None
mm = _monthnames.index(mm)+1
tm = string.splitfields(tm, ':')
if len(tm) == 2:
[thh, tmm] = tm
tss = '0'
else:
[thh, tmm, tss] = tm
try:
yy = string.atoi(yy)
dd = string.atoi(dd)
thh = string.atoi(thh)
tmm = string.atoi(tmm)
tss = string.atoi(tss)
except string.atoi_error:
return None
tuple = (yy, mm, dd, thh, tmm, tss, 0, 0, 0)
return tuple
# 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
file = '/ufs/guido/Mail/drafts/,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('date')
if date:
print 'ParsedDate:', time.asctime(date)
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()