"""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 # ----------------- try: import thread except ImportError: import dummy_thread as thread _counter_lock = thread.allocate_lock() del thread _counter = 0 def _get_next_counter(): global _counter _counter_lock.acquire() _counter += 1 result = _counter _counter_lock.release() return result _prefix = None def choose_boundary(): """Return a string usable as a multipart boundary. The string chosen is unique within a single program run, and incorporates the user id (if available), process id (if available), and current time. So it's very unlikely the returned string appears in message text, but there's no guarantee. The boundary contains dots so you have to quote it in the header.""" global _prefix import time if _prefix is None: import socket try: hostid = socket.gethostbyname(socket.gethostname()) except socket.gaierror: hostid = '127.0.0.1' try: uid = repr(os.getuid()) except AttributeError: uid = '1' try: pid = repr(os.getpid()) except AttributeError: pid = '1' _prefix = hostid + '.' + uid + '.' + pid return "%s.%.3f.%d" % (_prefix, time.time(), _get_next_counter()) # 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 encoding in decodetab: 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 encoding in encodetab: 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): (fd, tempname) = tempfile.mkstemp() temp = os.fdopen(fd, '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)