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Editing: rfc822.py
"""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) 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 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) 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 from warnings import warnpy3k warnpy3k("in 3.x, rfc822 has been removed in favor of the email package", stacklevel=2) __all__ = ["Message","AddressList","parsedate","parsedate_tz","mktime_tz"] _blanklines = ('\r\n', '\n') # Optimization for islast() class Message: """Represents a single RFC 2822-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 (AttributeError, IOError): seekable = 0 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 = lst = [] 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. lst.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. lst.append(line) self.dict[headerseen] = line[len(headerseen)+1:].strip() continue 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 # going. 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 RFC 2822-like formats with special header formats. """ i = line.find(':') if i > -1: return line[:i].lower() return None def islast(self, line): """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 free-text data. """ return False 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) lst = [] hit = 0 for line in self.headers: if line[:n].lower() == name: hit = 1 elif not line[:1].isspace(): hit = 0 if hit: lst.append(line) return lst 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) lst = [] hit = 0 for line in self.headers: if hit: if not line[:1].isspace(): break elif line[:n].lower() == name: hit = 1 if hit: lst.append(line) return lst 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. """ lst = self.getfirstmatchingheader(name) if not lst: return None lst[0] = lst[0][len(name) + 1:] return ''.join(lst) 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) 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 = AddressList(alladdrs) return a.addresslist 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 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.""" name = name.lower() if not name in self.dict: return del self.dict[name] name = name + ':' n = len(name) lst = [] 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: lst.append(i) for i in reversed(lst): del self.headers[i] def setdefault(self, name, default=""): lowername = name.lower() if lowername in self.dict: return self.dict[lowername] else: text = name + ": " + default for line in text.split("\n"): self.headers.append(line + "\n") self.dict[lowername] = default return default def has_key(self, name): """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 def __iter__(self): return iter(self.dict) 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): return ''.join(self.headers) # 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(s): """Remove quotes from a string.""" if len(s) > 1: if s.startswith('"') and s.endswith('"'): return s[1:-1].replace('\\\\', '\\').replace('\\"', '"') if s.startswith('<') and s.endswith('>'): return s[1:-1] return s def quote(s): """Add quotes around a string.""" return s.replace('\\', '\\\\').replace('"', '\\"') def parseaddr(address): """Parse an address into a (realname, mailaddr) tuple.""" a = AddressList(address) lst = a.addresslist if not lst: return (None, None) return lst[0] class AddrlistClass: """Address parser class by Ben Escoto. To understand what this class does, it helps to have a copy of RFC 2822 in front of you. http://www.faqs.org/rfcs/rfc2822.html 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 # Note that RFC 2822 now specifies `.' as obs-phrase, meaning that it # is obsolete syntax. RFC 2822 requires that we recognize obsolete # syntax, so allow dots in phrases. self.phraseends = self.atomends.replace('.', '') 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. """ result = [] ad = self.getaddress() while ad: result += ad ad = self.getaddress() return result 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 += 1 while self.pos < len(self.field): self.gotonext() if self.pos < fieldlen and self.field[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 += 1 self.gotonext() if self.pos < len(self.field) and self.field[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 += 1 self.gotonext() adlist = "" while self.pos < len(self.field): if expectroute: self.getdomain() expectroute = 0 elif self.field[self.pos] == '>': self.pos += 1 break elif self.field[self.pos] == '@': self.pos += 1 expectroute = 1 elif self.field[self.pos] == ':': self.pos += 1 else: adlist = self.getaddrspec() self.pos += 1 break self.gotonext() return adlist def getaddrspec(self): """Parse an RFC 2822 addr-spec.""" aslist = [] self.gotonext() while self.pos < len(self.field): if self.field[self.pos] == '.': aslist.append('.') 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 += 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 += 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 += 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 2822 comments are allowed within the parsed fragment. """ if self.field[self.pos] != beginchar: return '' slist = [''] quote = 0 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 += 1 break elif allowcomments and self.field[self.pos] == '(': slist.append(self.getcomment()) continue # have already advanced pos from getcomment elif self.field[self.pos] == '\\': quote = 1 else: slist.append(self.field[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 2822 domain-literal.""" return '[%s]' % self.getdelimited('[', ']\r', 0) def getatom(self, atomends=None): """Parse an RFC 2822 atom. Optional atomends specifies a different set of end token delimiters (the default is to use self.atomends). This is used e.g. in getphraselist() since phrase endings must not include the `.' (which is legal in phrases).""" atomlist = [''] if atomends is None: atomends = self.atomends while self.pos < len(self.field): if self.field[self.pos] in atomends: break else: atomlist.append(self.field[self.pos]) self.pos += 1 return ''.join(atomlist) def getphraselist(self): """Parse a sequence of RFC 2822 phrases. A phrase is a sequence of words, which are in turn either RFC 2822 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 += 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.phraseends: break else: plist.append(self.getatom(self.phraseends)) return plist class AddressList(AddrlistClass): """An AddressList encapsulates a list of parsed RFC 2822 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. """ if not data: return None data = data.split() if data[0][-1] in (',', '.') or data[0].lower() in _daynames: # There's a dayname here. Skip it del data[0] else: # no space after the "weekday,"? i = data[0].rfind(',') if i >= 0: data[0] = data[0][i+1:] 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 tz in _timezones: 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) return (yy, mm, dd, thh, tmm, tss, 0, 1, 0, tzoffset) def parsedate(data): """Convert a time string to a time tuple.""" t = parsedate_tz(data) if t is None: return t return t[:9] 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 According to RFC 1123, day and month names must always be in English. If not for that, this code could use strftime(). It can't because strftime() honors the locale and could generate non-English names. """ if timeval is None: timeval = time.time() timeval = time.gmtime(timeval) return "%s, %02d %s %04d %02d:%02d:%02d GMT" % ( ("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun")[timeval[6]], timeval[2], ("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec")[timeval[1]-1], timeval[0], timeval[3], timeval[4], timeval[5]) # 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 += 1 print 'Lines:', n print '-'*70 print 'len =', len(m) if 'Date' in m: print 'Date =', m['Date'] if 'X-Nonsense' in m: pass print 'keys =', m.keys() print 'values =', m.values() print 'items =', m.items()
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