528 lines
13 KiB
Python
528 lines
13 KiB
Python
# RFC-822 message manipulation class.
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#
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# XXX This is only a very rough sketch of a full RFC-822 parser;
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# in particular the tokenizing of addresses does not adhere to all the
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# quoting rules.
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#
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# Directions for use:
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#
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# To create a Message object: first open a file, e.g.:
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# fp = open(file, 'r')
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# (or use any other legal way of getting an open file object, e.g. use
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# sys.stdin or call os.popen()).
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# Then pass the open file object to the Message() constructor:
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# m = Message(fp)
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#
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# To get the text of a particular header there are several methods:
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# str = m.getheader(name)
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# str = m.getrawheader(name)
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# where name is the name of the header, e.g. 'Subject'.
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# The difference is that getheader() strips the leading and trailing
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# whitespace, while getrawheader() doesn't. Both functions retain
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# embedded whitespace (including newlines) exactly as they are
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# specified in the header, and leave the case of the text unchanged.
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#
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# For addresses and address lists there are functions
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# realname, mailaddress = m.getaddr(name) and
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# list = m.getaddrlist(name)
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# where the latter returns a list of (realname, mailaddr) tuples.
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#
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# There is also a method
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# time = m.getdate(name)
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# which parses a Date-like field and returns a time-compatible tuple,
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# i.e. a tuple such as returned by time.localtime() or accepted by
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# time.mktime().
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#
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# See the class definition for lower level access methods.
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#
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# There are also some utility functions here.
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import regex
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import string
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import time
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_blanklines = ('\r\n', '\n') # Optimization for islast()
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class Message:
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# Initialize the class instance and read the headers.
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def __init__(self, fp, seekable = 1):
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self.fp = fp
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self.seekable = seekable
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self.startofheaders = None
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self.startofbody = None
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#
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if self.seekable:
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try:
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self.startofheaders = self.fp.tell()
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except IOError:
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self.seekable = 0
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#
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self.readheaders()
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#
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if self.seekable:
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try:
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self.startofbody = self.fp.tell()
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except IOError:
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self.seekable = 0
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# Rewind the file to the start of the body (if seekable).
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def rewindbody(self):
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if not self.seekable:
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raise IOError, "unseekable file"
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self.fp.seek(self.startofbody)
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# Read header lines up to the entirely blank line that
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# terminates them. The (normally blank) line that ends the
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# headers is skipped, but not included in the returned list.
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# If a non-header line ends the headers, (which is an error),
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# an attempt is made to backspace over it; it is never
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# included in the returned list.
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#
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# The variable self.status is set to the empty string if all
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# went well, otherwise it is an error message.
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# The variable self.headers is a completely uninterpreted list
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# of lines contained in the header (so printing them will
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# reproduce the header exactly as it appears in the file).
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def readheaders(self):
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self.dict = {}
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self.unixfrom = ''
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self.headers = list = []
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self.status = ''
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headerseen = ""
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firstline = 1
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while 1:
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line = self.fp.readline()
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if not line:
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self.status = 'EOF in headers'
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break
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# Skip unix From name time lines
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if firstline and line[:5] == 'From ':
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self.unixfrom = self.unixfrom + line
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continue
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firstline = 0
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if self.islast(line):
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break
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elif headerseen and line[0] in ' \t':
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# It's a continuation line.
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list.append(line)
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x = (self.dict[headerseen] + "\n " +
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string.strip(line))
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self.dict[headerseen] = string.strip(x)
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elif ':' in line:
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# It's a header line.
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list.append(line)
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i = string.find(line, ':')
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headerseen = string.lower(line[:i])
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self.dict[headerseen] = string.strip(
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line[i+1:])
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else:
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# It's not a header line; stop here.
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if not headerseen:
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self.status = 'No headers'
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else:
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self.status = 'Bad header'
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# Try to undo the read.
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if self.seekable:
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self.fp.seek(-len(line), 1)
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else:
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self.status = \
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self.status + '; bad seek'
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break
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# Method to determine whether a line is a legal end of
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# RFC-822 headers. You may override this method if your
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# application wants to bend the rules, e.g. to strip trailing
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# whitespace, or to recognise MH template separators
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# ('--------'). For convenience (e.g. for code reading from
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# sockets) a line consisting of \r\n also matches.
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def islast(self, line):
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return line in _blanklines
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# Look through the list of headers and find all lines matching
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# a given header name (and their continuation lines).
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# A list of the lines is returned, without interpretation.
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# If the header does not occur, an empty list is returned.
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# If the header occurs multiple times, all occurrences are
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# returned. Case is not important in the header name.
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def getallmatchingheaders(self, name):
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name = string.lower(name) + ':'
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n = len(name)
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list = []
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hit = 0
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for line in self.headers:
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if string.lower(line[:n]) == name:
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hit = 1
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elif line[:1] not in string.whitespace:
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hit = 0
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if hit:
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list.append(line)
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return list
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# Similar, but return only the first matching header (and its
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# continuation lines).
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def getfirstmatchingheader(self, name):
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name = string.lower(name) + ':'
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n = len(name)
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list = []
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hit = 0
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for line in self.headers:
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if hit:
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if line[:1] not in string.whitespace:
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break
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elif string.lower(line[:n]) == name:
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hit = 1
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if hit:
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list.append(line)
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return list
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# A higher-level interface to getfirstmatchingheader().
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# Return a string containing the literal text of the header
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# but with the keyword stripped. All leading, trailing and
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# embedded whitespace is kept in the string, however.
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# Return None if the header does not occur.
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def getrawheader(self, name):
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list = self.getfirstmatchingheader(name)
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if not list:
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return None
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list[0] = list[0][len(name) + 1:]
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return string.joinfields(list, '')
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# The normal interface: return a stripped version of the
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# header value with a name, or None if it doesn't exist. This
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# uses the dictionary version which finds the *last* such
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# header.
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def getheader(self, name):
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try:
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return self.dict[string.lower(name)]
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except KeyError:
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return None
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# Retrieve a single address from a header as a tuple, e.g.
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# ('Guido van Rossum', 'guido@cwi.nl').
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def getaddr(self, name):
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try:
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data = self[name]
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except KeyError:
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return None, None
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return parseaddr(data)
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# Retrieve a list of addresses from a header, where each
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# address is a tuple as returned by getaddr().
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def getaddrlist(self, name):
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# XXX This function is not really correct. The split
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# on ',' might fail in the case of commas within
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# quoted strings.
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try:
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data = self[name]
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except KeyError:
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return []
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data = string.splitfields(data, ',')
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for i in range(len(data)):
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data[i] = parseaddr(data[i])
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return data
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# Retrieve a date field from a header as a tuple compatible
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# with time.mktime().
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def getdate(self, name):
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try:
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data = self[name]
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except KeyError:
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return None
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return parsedate(data)
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# Retrieve a date field from a header as a 10-tuple.
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# The first 9 elements make up a tuple compatible
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# with time.mktime(), and the 10th is the offset
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# of the poster's time zone from GMT/UTC.
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def getdate_tz(self, name):
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try:
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data = self[name]
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except KeyError:
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return None
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return parsedate_tz(data)
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# Access as a dictionary (only finds *last* header of each type):
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def __len__(self):
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return len(self.dict)
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def __getitem__(self, name):
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return self.dict[string.lower(name)]
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def has_key(self, name):
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return self.dict.has_key(string.lower(name))
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def keys(self):
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return self.dict.keys()
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def values(self):
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return self.dict.values()
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def items(self):
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return self.dict.items()
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# Utility functions
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# -----------------
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# XXX Should fix these to be really conformant.
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# XXX The inverses of the parse functions may also be useful.
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# Remove quotes from a string.
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def unquote(str):
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if len(str) > 1:
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if str[0] == '"' and str[-1:] == '"':
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return str[1:-1]
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if str[0] == '<' and str[-1:] == '>':
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return str[1:-1]
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return str
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# Parse an address into (name, address) tuple
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def parseaddr(address):
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import string
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str = ''
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email = ''
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comment = ''
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backslash = 0
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dquote = 0
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space = 0
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paren = 0
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bracket = 0
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seen_bracket = 0
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for c in address:
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if backslash:
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str = str + c
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backslash = 0
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continue
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if c == '\\':
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backslash = 1
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continue
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if dquote:
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if c == '"':
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dquote = 0
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else:
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str = str + c
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continue
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if c == '"':
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dquote = 1
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continue
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if c in string.whitespace:
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space = 1
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continue
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if space:
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str = str + ' '
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space = 0
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if paren:
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if c == '(':
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paren = paren + 1
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str = str + c
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continue
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if c == ')':
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paren = paren - 1
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if paren == 0:
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comment = comment + str
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str = ''
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continue
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if c == '(':
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paren = paren + 1
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if bracket:
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email = email + str
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str = ''
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elif not seen_bracket:
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email = email + str
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str = ''
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continue
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if bracket:
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if c == '>':
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bracket = 0
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email = email + str
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str = ''
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continue
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if c == '<':
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bracket = 1
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seen_bracket = 1
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comment = comment + str
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str = ''
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email = ''
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continue
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if c == '#' and not bracket and not paren:
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# rest is comment
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break
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str = str + c
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if str:
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if seen_bracket:
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if bracket:
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email = str
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else:
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comment = comment + str
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else:
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if paren:
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comment = comment + str
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else:
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email = email + str
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return string.strip(comment), string.strip(email)
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# Parse a date field
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_monthnames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul',
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'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
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_daynames = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
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# The timezone table does not include the military time zones defined
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# in RFC822, other than Z. According to RFC1123, the description in
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# RFC822 gets the signs wrong, so we can't rely on any such time
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# zones. RFC1123 recommends that numeric timezone indicators be used
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# instead of timezone names.
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_timezones = {'UT':0, 'UTC':0, 'GMT':0, 'Z':0,
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'AST': -400, 'ADT': -300, # Atlantic standard
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'EST': -500, 'EDT': -400, # Eastern
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'CST': -600, 'CDT':-500, # Centreal
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'MST':-700, 'MDT':-600, # Mountain
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'PST':-800, 'PDT':-700 # Pacific
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}
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def parsedate_tz(data):
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data = string.split(data)
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if data[0][-1] == ',' or data[0] in _daynames:
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# There's a dayname here. Skip it
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del data[0]
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if len(data) == 3: # RFC 850 date, deprecated
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stuff = string.split(data[0], '-')
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if len(stuff) == 3:
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data = stuff + data[1:]
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if len(data) == 4:
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s = data[3]
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i = string.find(s, '+')
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if i > 0:
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data[3:] = [s[:i], s[i+1:]]
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else:
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data.append('') # Dummy tz
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if len(data) < 5:
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return None
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data = data[:5]
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[dd, mm, yy, tm, tz] = data
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if not mm in _monthnames:
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dd, mm, yy, tm, tz = mm, dd, tm, yy, tz
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if not mm in _monthnames:
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return None
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mm = _monthnames.index(mm)+1
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tm = string.splitfields(tm, ':')
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if len(tm) == 2:
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[thh, tmm] = tm
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tss = '0'
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else:
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[thh, tmm, tss] = tm
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try:
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yy = string.atoi(yy)
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dd = string.atoi(dd)
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thh = string.atoi(thh)
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tmm = string.atoi(tmm)
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tss = string.atoi(tss)
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except string.atoi_error:
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return None
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tzoffset=0
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tz=string.upper(tz)
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if _timezones.has_key(tz):
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tzoffset=_timezones[tz]
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else:
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try:
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tzoffset=string.atoi(tz)
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except string.atoi_error:
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pass
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# Convert a timezone offset into seconds ; -0500 -> -18000
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if tzoffset<0: tzsign=-1
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else: tzsign=1
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tzoffset=tzoffset*tzsign
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tzoffset = tzsign * ( (tzoffset/100)*3600 + (tzoffset % 100)*60)
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tuple = (yy, mm, dd, thh, tmm, tss, 0, 0, 0, tzoffset)
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return tuple
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def parsedate(data):
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t=parsedate_tz(data)
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if type(t)==type( () ):
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return t[:9]
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else: return t
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def mktime_tz(data):
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"""Turn a 10-tuple as returned by parsedate_tz() into a UTC timestamp.
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Minor glitch: this first interprets the first 8 elements as a
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local time and then compensates for the timezone difference;
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this may yield a slight error around daylight savings time
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switch dates. Not enough to worry about for common use.
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"""
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t = time.mktime(data[:8] + (0,))
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return t + data[9] - time.timezone
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# When used as script, run a small test program.
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# The first command line argument must be a filename containing one
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# message in RFC-822 format.
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if __name__ == '__main__':
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import sys, os
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file = os.path.join(os.environ['HOME'], 'Mail/inbox/1')
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if sys.argv[1:]: file = sys.argv[1]
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f = open(file, 'r')
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m = Message(f)
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print 'From:', m.getaddr('from')
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print 'To:', m.getaddrlist('to')
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print 'Subject:', m.getheader('subject')
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print 'Date:', m.getheader('date')
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date = m.getdate_tz('date')
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if date:
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print 'ParsedDate:', time.asctime(date[:-1]),
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hhmmss = date[-1]
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hhmm, ss = divmod(hhmmss, 60)
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hh, mm = divmod(hhmm, 60)
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print "%+03d%02d" % (hh, mm),
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if ss: print ".%02d" % ss,
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print
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else:
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print 'ParsedDate:', None
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m.rewindbody()
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n = 0
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while f.readline():
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n = n + 1
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print 'Lines:', n
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print '-'*70
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print 'len =', len(m)
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if m.has_key('Date'): print 'Date =', m['Date']
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if m.has_key('X-Nonsense'): pass
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print 'keys =', m.keys()
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print 'values =', m.values()
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print 'items =', m.items()
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