| # RFC-822 message manipulation class. |
| # |
| # XXX This is only a very rough sketch of a full RFC-822 parser; |
| # additional methods are needed to parse addresses and dates, and to |
| # tokenize lines according to various other syntax 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 init() method of Message: |
| # m = Message().init(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. |
| # |
| # See the class definition for lower level access methods. |
| # |
| # There are also some utility functions here. |
| |
| |
| import regex |
| import string |
| |
| |
| 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 |
| # |
| return self |
| |
| |
| # 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): |
| # 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 accept lines |
| # ending in '\r\n', to strip trailing whitespace, or to |
| # recognise MH template separators ('--------'). |
| |
| def islast(self, line): |
| return line == '\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 string.lower(line[:n]) == name: |
| hit = 1 |
| elif line[:1] not in string.whitespace: |
| if hit: |
| break |
| 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) |
| |
| |
| # XXX The next step would be to define self.getaddr(name) |
| # and self.getaddrlist(name) which would parse a header |
| # consisting of a single mail address and a number of mail |
| # addresses, respectively. Lower level functions would be |
| # parseaddr(string) and parseaddrlist(string). |
| |
| # XXX Similar, there would be a function self.getdate(name) to |
| # return a date in canonical form (perhaps a number compatible |
| # to time.time()) and a function parsedate(string). |
| |
| # XXX The inverses of the parse functions may also be useful. |
| |
| |
| |
| |
| # Utility functions |
| # ----------------- |
| |
| |
| # Remove quotes from a string. |
| # XXX Should fix this to be really conformant. |
| |
| 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 |