"""Various tools used by MIME-reading or MIME-writing programs."""
import os
import rfc822
import tempfile
__all__ = ["Message","choose_boundary","encode","decode","copyliteral",
"copybinary"]
class Message(rfc822.Message):
"""A derived class of rfc822.Message that knows about MIME headers and
contains some hooks for decoding encoded and multipart messages."""
def __init__(self, fp, seekable = 1):
rfc822.Message.__init__(self, fp, seekable)
self.encodingheader = \
self.getheader('content-transfer-encoding')
self.typeheader = \
self.getheader('content-type')
self.parsetype()
self.parseplist()
def parsetype(self):
str = self.typeheader
if str is None:
str = 'text/plain'
if ';' in str:
i = str.index(';')
self.plisttext = str[i:]
str = str[:i]
else:
self.plisttext = ''
fields = str.split('/')
for i in range(len(fields)):
fields[i] = fields[i].strip().lower()
self.type = '/'.join(fields)
self.maintype = fields[0]
self.subtype = '/'.join(fields[1:])
def parseplist(self):
str = self.plisttext
self.plist = []
while str[:1] == ';':
str = str[1:]
if ';' in str:
# XXX Should parse quotes!
end = str.index(';')
else:
end = len(str)
f = str[:end]
if '=' in f:
i = f.index('=')
f = f[:i].strip().lower() + \
'=' + f[i+1:].strip()
self.plist.append(f.strip())
str = str[end:]
def getplist(self):
return self.plist
def getparam(self, name):
name = name.lower() + '='
n = len(name)
for p in self.plist:
if p[:n] == name:
return rfc822.unquote(p[n:])
return None
def getparamnames(self):
result = []
for p in self.plist:
i = p.find('=')
if i >= 0:
result.append(p[:i].lower())
return result
def getencoding(self):
if self.encodingheader is None:
return '7bit'
return self.encodingheader.lower()
def gettype(self):
return self.type
def getmaintype(self):
return self.maintype
def getsubtype(self):
return self.subtype
# Utility functions
# -----------------
_prefix = None
def choose_boundary():
"""Return a random string usable as a multipart boundary.
The method used is so that it is *very* unlikely that the same
string of characters will every occur again in the Universe,
so the caller needn't check the data it is packing for the
occurrence of the boundary.
The boundary contains dots so you have to quote it in the header."""
global _prefix
import time
import random
if _prefix is None:
import socket
import os
hostid = socket.gethostbyname(socket.gethostname())
try:
uid = `os.getuid()`
except:
uid = '1'
try:
pid = `os.getpid()`
except:
pid = '1'
_prefix = hostid + '.' + uid + '.' + pid
timestamp = '%.3f' % time.time()
seed = `random.randint(0, 32767)`
return _prefix + '.' + timestamp + '.' + seed
# Subroutines for decoding some common content-transfer-types
def decode(input, output, encoding):
"""Decode common content-transfer-encodings (base64, quopri, uuencode)."""
if encoding == 'base64':
import base64
return base64.decode(input, output)
if encoding == 'quoted-printable':
import quopri
return quopri.decode(input, output)
if encoding in ('uuencode', 'x-uuencode', 'uue', 'x-uue'):
import uu
return uu.decode(input, output)
if encoding in ('7bit', '8bit'):
return output.write(input.read())
if decodetab.has_key(encoding):
pipethrough(input, decodetab[encoding], output)
else:
raise ValueError, \
'unknown Content-Transfer-Encoding: %s' % encoding
def encode(input, output, encoding):
"""Encode common content-transfer-encodings (base64, quopri, uuencode)."""
if encoding == 'base64':
import base64
return base64.encode(input, output)
if encoding == 'quoted-printable':
import quopri
return quopri.encode(input, output, 0)
if encoding in ('uuencode', 'x-uuencode', 'uue', 'x-uue'):
import uu
return uu.encode(input, output)
if encoding in ('7bit', '8bit'):
return output.write(input.read())
if encodetab.has_key(encoding):
pipethrough(input, encodetab[encoding], output)
else:
raise ValueError, \
'unknown Content-Transfer-Encoding: %s' % encoding
# The following is no longer used for standard encodings
# XXX This requires that uudecode and mmencode are in $PATH
uudecode_pipe = '''(
TEMP=/tmp/@uu.$$
sed "s%^begin [0-7][0-7]* .*%begin 600 $TEMP%" | uudecode
cat $TEMP
rm $TEMP
)'''
decodetab = {
'uuencode': uudecode_pipe,
'x-uuencode': uudecode_pipe,
'uue': uudecode_pipe,
'x-uue': uudecode_pipe,
'quoted-printable': 'mmencode -u -q',
'base64': 'mmencode -u -b',
}
encodetab = {
'x-uuencode': 'uuencode tempfile',
'uuencode': 'uuencode tempfile',
'x-uue': 'uuencode tempfile',
'uue': 'uuencode tempfile',
'quoted-printable': 'mmencode -q',
'base64': 'mmencode -b',
}
def pipeto(input, command):
pipe = os.popen(command, 'w')
copyliteral(input, pipe)
pipe.close()
def pipethrough(input, command, output):
tempname = tempfile.mktemp()
temp = open(tempname, 'w')
copyliteral(input, temp)
temp.close()
pipe = os.popen(command + ' <' + tempname, 'r')
copybinary(pipe, output)
pipe.close()
os.unlink(tempname)
def copyliteral(input, output):
while 1:
line = input.readline()
if not line: break
output.write(line)
def copybinary(input, output):
BUFSIZE = 8192
while 1:
line = input.read(BUFSIZE)
if not line: break
output.write(line)
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