# Copyright (C) 2001,2002 Python Software Foundation # Author: barry@zope.com (Barry Warsaw) """Basic message object for the email package object model. """ import re import warnings from cStringIO import StringIO from types import ListType, TupleType, StringType # Intrapackage imports from email import Errors from email import Utils from email import Charset SEMISPACE = '; ' try: True, False except NameError: True = 1 False = 0 # Regular expression used to split header parameters. BAW: this may be too # simple. It isn't strictly RFC 2045 (section 5.1) compliant, but it catches # most headers found in the wild. We may eventually need a full fledged # parser eventually. paramre = re.compile(r'\s*;\s*') # Regular expression that matches `special' characters in parameters, the # existance of which force quoting of the parameter value. tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]') # Helper functions def _formatparam(param, value=None, quote=True): """Convenience function to format and return a key=value pair. This will quote the value if needed or if quote is true. """ if value is not None and len(value) > 0: # TupleType is used for RFC 2231 encoded parameter values where items # are (charset, language, value). charset is a string, not a Charset # instance. if isinstance(value, TupleType): # Encode as per RFC 2231 param += '*' value = Utils.encode_rfc2231(value[2], value[0], value[1]) # BAW: Please check this. I think that if quote is set it should # force quoting even if not necessary. if quote or tspecials.search(value): return '%s="%s"' % (param, Utils.quote(value)) else: return '%s=%s' % (param, value) else: return param def _unquotevalue(value): if isinstance(value, TupleType): return value[0], value[1], Utils.unquote(value[2]) else: return Utils.unquote(value) class Message: """Basic message object for use inside the object tree. A message object is defined as something that has a bunch of RFC 2822 headers and a payload. If the body of the message is a multipart, then the payload is a list of Messages, otherwise it is a string. These objects implement part of the `mapping' interface, which assumes there is exactly one occurrance of the header per message. Some headers do in fact appear multiple times (e.g. Received) and for those headers, you must use the explicit API to set or get all the headers. Not all of the mapping methods are implemented. """ def __init__(self): self._headers = [] self._unixfrom = None self._payload = None self._charset = None # Defaults for multipart messages self.preamble = self.epilogue = None # Default content type self._default_type = 'text/plain' def __str__(self): """Return the entire formatted message as a string. This includes the headers, body, and `unixfrom' line. """ return self.as_string(unixfrom=True) def as_string(self, unixfrom=False): """Return the entire formatted message as a string. Optional `unixfrom' when True, means include the Unix From_ envelope header. """ from email.Generator import Generator fp = StringIO() g = Generator(fp) g.flatten(self, unixfrom=unixfrom) return fp.getvalue() def is_multipart(self): """Return True if the message consists of multiple parts.""" if type(self._payload) is ListType: return True return False # # Unix From_ line # def set_unixfrom(self, unixfrom): self._unixfrom = unixfrom def get_unixfrom(self): return self._unixfrom # # Payload manipulation. # def add_payload(self, payload): """Add the given payload to the current payload. If the current payload is empty, then the current payload will be made a scalar, set to the given value. """ warnings.warn('add_payload() is deprecated, use attach() instead.', DeprecationWarning, 2) if self._payload is None: self._payload = payload elif isinstance(self._payload, ListType): self._payload.append(payload) elif self.get_main_type() not in (None, 'multipart'): raise Errors.MultipartConversionError( 'Message main content type must be "multipart" or missing') else: self._payload = [self._payload, payload] def attach(self, payload): """Add the given payload to the current payload. The current payload will always be a list of objects after this method is called. If you want to set the payload to a scalar object (e.g. because you're attaching a message/rfc822 subpart), use set_payload() instead. """ if self._payload is None: self._payload = [payload] else: self._payload.append(payload) def get_payload(self, i=None, decode=False): """Return a reference to the payload. The payload is typically either a list object or a string. If you mutate the list object, you modify the message's payload in place. Optional i returns that index into the payload. Optional decode is a flag indicating whether the payload should be decoded or not, according to the Content-Transfer-Encoding header. When True and the message is not a multipart, the payload will be decoded if this header's value is `quoted-printable' or `base64'. If some other encoding is used, or the header is missing, the payload is returned as-is (undecoded). If the message is a multipart and the decode flag is True, then None is returned. """ if i is None: payload = self._payload elif not isinstance(self._payload, ListType): raise TypeError, i else: payload = self._payload[i] if decode: if self.is_multipart(): return None cte = self.get('content-transfer-encoding', '') if cte.lower() == 'quoted-printable': return Utils._qdecode(payload) elif cte.lower() == 'base64': return Utils._bdecode(payload) # Everything else, including encodings with 8bit or 7bit are returned # unchanged. return payload def set_payload(self, payload, charset=None): """Set the payload to the given value. Optionally set the charset, which must be a Charset instance.""" self._payload = payload if charset is not None: self.set_charset(charset) def set_charset(self, charset): """Set the charset of the payload to a given character set. charset can be a string or a Charset object. If it is a string, it will be converted to a Charset object by calling Charset's constructor. If charset is None, the charset parameter will be removed from the Content-Type field. Anything else will generate a TypeError. The message will be assumed to be a text message encoded with charset.input_charset. It will be converted to charset.output_charset and encoded properly, if needed, when generating the plain text representation of the message. MIME headers (MIME-Version, Content-Type, Content-Transfer-Encoding) will be added as needed. """ if charset is None: self.del_param('charset') self._charset = None return if isinstance(charset, StringType): charset = Charset.Charset(charset) if not isinstance(charset, Charset.Charset): raise TypeError, charset # BAW: should we accept strings that can serve as arguments to the # Charset constructor? self._charset = charset if not self.has_key('MIME-Version'): self.add_header('MIME-Version', '1.0') if not self.has_key('Content-Type'): self.add_header('Content-Type', 'text/plain', charset=charset.get_output_charset()) else: self.set_param('charset', charset.get_output_charset()) if not self.has_key('Content-Transfer-Encoding'): cte = charset.get_body_encoding() if callable(cte): cte(self) else: self.add_header('Content-Transfer-Encoding', cte) def get_charset(self): """Return the Charset object associated with the message's payload.""" return self._charset # # MAPPING INTERFACE (partial) # def __len__(self): """Return the total number of headers, including duplicates.""" return len(self._headers) def __getitem__(self, name): """Get a header value. Return None if the header is missing instead of raising an exception. Note that if the header appeared multiple times, exactly which occurrance gets returned is undefined. Use getall() to get all the values matching a header field name. """ return self.get(name) def __setitem__(self, name, val): """Set the value of a header. Note: this does not overwrite an existing header with the same field name. Use __delitem__() first to delete any existing headers. """ self._headers.append((name, val)) def __delitem__(self, name): """Delete all occurrences of a header, if present. Does not raise an exception if the header is missing. """ name = name.lower() newheaders = [] for k, v in self._headers: if k.lower() <> name: newheaders.append((k, v)) self._headers = newheaders def __contains__(self, key): return key.lower() in [k.lower() for k, v in self._headers] def has_key(self, name): """Return true if the message contains the header.""" missing = [] return self.get(name, missing) is not missing def keys(self): """Return a list of all the message's header field names. These will be sorted in the order they appeared in the original message, and may contain duplicates. Any fields deleted and re-inserted are always appended to the header list. """ return [k for k, v in self._headers] def values(self): """Return a list of all the message's header values. These will be sorted in the order they appeared in the original message, and may contain duplicates. Any fields deleted and re-inserted are always appended to the header list. """ return [v for k, v in self._headers] def items(self): """Get all the message's header fields and values. These will be sorted in the order they appeared in the original message, and may contain duplicates. Any fields deleted and re-inserted are always appended to the header list. """ return self._headers[:] def get(self, name, failobj=None): """Get a header value. Like __getitem__() but return failobj instead of None when the field is missing. """ name = name.lower() for k, v in self._headers: if k.lower() == name: return v return failobj # # Additional useful stuff # def get_all(self, name, failobj=None): """Return a list of all the values for the named field. These will be sorted in the order they appeared in the original message, and may contain duplicates. Any fields deleted and re-inserted are always appended to the header list. If no such fields exist, failobj is returned (defaults to None). """ values = [] name = name.lower() for k, v in self._headers: if k.lower() == name: values.append(v) if not values: return failobj return values def add_header(self, _name, _value, **_params): """Extended header setting. name is the header field to add. keyword arguments can be used to set additional parameters for the header field, with underscores converted to dashes. Normally the parameter will be added as key="value" unless value is None, in which case only the key will be added. Example: msg.add_header('content-disposition', 'attachment', filename='bud.gif') """ parts = [] for k, v in _params.items(): if v is None: parts.append(k.replace('_', '-')) else: parts.append(_formatparam(k.replace('_', '-'), v)) if _value is not None: parts.insert(0, _value) self._headers.append((_name, SEMISPACE.join(parts))) def replace_header(self, _name, _value): """Replace a header. Replace the first matching header found in the message, retaining header order and case. If no matching header was found, a KeyError is raised. """ _name = _name.lower() for i, (k, v) in zip(range(len(self._headers)), self._headers): if k.lower() == _name: self._headers[i] = (k, _value) break else: raise KeyError, _name # # These methods are silently deprecated in favor of get_content_type() and # friends (see below). They will be noisily deprecated in email 3.0. # def get_type(self, failobj=None): """Returns the message's content type. The returned string is coerced to lowercase and returned as a single string of the form `maintype/subtype'. If there was no Content-Type header in the message, failobj is returned (defaults to None). """ missing = [] value = self.get('content-type', missing) if value is missing: return failobj return paramre.split(value)[0].lower().strip() def get_main_type(self, failobj=None): """Return the message's main content type if present.""" missing = [] ctype = self.get_type(missing) if ctype is missing: return failobj if ctype.count('/') <> 1: return failobj return ctype.split('/')[0] def get_subtype(self, failobj=None): """Return the message's content subtype if present.""" missing = [] ctype = self.get_type(missing) if ctype is missing: return failobj if ctype.count('/') <> 1: return failobj return ctype.split('/')[1] # # Use these three methods instead of the three above. # def get_content_type(self): """Returns the message's content type. The returned string is coerced to lowercase and returned as a ingle string of the form `maintype/subtype'. If there was no Content-Type header in the message, the default type as give by get_default_type() will be returned. Since messages always have a default type this will always return a value. The current state of RFC standards define a message's default type to be text/plain unless it appears inside a multipart/digest container, in which case it would be message/rfc822. """ missing = [] value = self.get('content-type', missing) if value is missing: # This should have no parameters return self.get_default_type() ctype = paramre.split(value)[0].lower().strip() # RFC 2045, section 5.2 says if its invalid, use text/plain if ctype.count('/') <> 1: return 'text/plain' return ctype def get_content_maintype(self): """Returns the message's main content type. This is the `maintype' part of the string returned by get_content_type(). If no slash is found in the full content type, a ValueError is raised. """ ctype = self.get_content_type() return ctype.split('/')[0] def get_content_subtype(self): """Returns the message's sub content type. This is the `subtype' part of the string returned by get_content_type(). If no slash is found in the full content type, a ValueError is raised. """ ctype = self.get_content_type() return ctype.split('/')[1] def get_default_type(self): """Return the `default' content type. Most messages have a default content type of text/plain, except for messages that are subparts of multipart/digest containers. Such subparts then have a default content type of message/rfc822. """ return self._default_type def set_default_type(self, ctype): """Set the `default' content type. ctype should be either "text/plain" or "message/rfc822", although this is not enforced. The default content type is not stored in the Content-Type header. """ self._default_type = ctype def _get_params_preserve(self, failobj, header): # Like get_params() but preserves the quoting of values. BAW: # should this be part of the public interface? missing = [] value = self.get(header, missing) if value is missing: return failobj params = [] for p in paramre.split(value): try: name, val = p.split('=', 1) name = name.strip() val = val.strip() except ValueError: # Must have been a bare attribute name = p.strip() val = '' params.append((name, val)) params = Utils.decode_params(params) return params def get_params(self, failobj=None, header='content-type', unquote=True): """Return the message's Content-Type parameters, as a list. The elements of the returned list are 2-tuples of key/value pairs, as split on the `=' sign. The left hand side of the `=' is the key, while the right hand side is the value. If there is no `=' sign in the parameter the value is the empty string. The value is as described in the get_param() method. Optional failobj is the object to return if there is no Content-Type header. Optional header is the header to search instead of Content-Type. If unquote is True, the value is unquoted. """ missing = [] params = self._get_params_preserve(missing, header) if params is missing: return failobj if unquote: return [(k, _unquotevalue(v)) for k, v in params] else: return params def get_param(self, param, failobj=None, header='content-type', unquote=True): """Return the parameter value if found in the Content-Type header. Optional failobj is the object to return if there is no Content-Type header, or the Content-Type header has no such parameter. Optional header is the header to search instead of Content-Type. Parameter keys are always compared case insensitively. The return value can either be a string, or a 3-tuple if the parameter was RFC 2231 encoded. When it's a 3-tuple, the elements of the value are of the form (CHARSET, LANGUAGE, VALUE), where LANGUAGE may be the empty string. Your application should be prepared to deal with these, and can convert the parameter to a Unicode string like so: param = msg.get_param('foo') if isinstance(param, tuple): param = unicode(param[2], param[0]) In any case, the parameter value (either the returned string, or the VALUE item in the 3-tuple) is always unquoted, unless unquote is set to False. """ if not self.has_key(header): return failobj for k, v in self._get_params_preserve(failobj, header): if k.lower() == param.lower(): if unquote: return _unquotevalue(v) else: return v return failobj def set_param(self, param, value, header='Content-Type', requote=True, charset=None, language=''): """Set a parameter in the Content-Type header. If the parameter already exists in the header, its value will be replaced with the new value. If header is Content-Type and has not yet been defined in this message, it will be set to "text/plain" and the new parameter and value will be appended, as per RFC 2045. An alternate header can specified in the header argument, and all parameters will be quoted as appropriate unless requote is False. If charset is specified the parameter will be encoded according to RFC 2231. In this case language is optional. """ if not isinstance(value, TupleType) and charset: value = (charset, language, value) if not self.has_key(header) and header.lower() == 'content-type': ctype = 'text/plain' else: ctype = self.get(header) if not self.get_param(param, header=header): if not ctype: ctype = _formatparam(param, value, requote) else: ctype = SEMISPACE.join( [ctype, _formatparam(param, value, requote)]) else: ctype = '' for old_param, old_value in self.get_params(header=header, unquote=requote): append_param = '' if old_param.lower() == param.lower(): append_param = _formatparam(param, value, requote) else: append_param = _formatparam(old_param, old_value, requote) if not ctype: ctype = append_param else: ctype = SEMISPACE.join([ctype, append_param]) if ctype <> self.get(header): del self[header] self[header] = ctype def del_param(self, param, header='content-type', requote=True): """Remove the given parameter completely from the Content-Type header. The header will be re-written in place without param or its value. All values will be quoted as appropriate unless requote is False. """ if not self.has_key(header): return new_ctype = '' for p, v in self.get_params(header, unquote=requote): if p.lower() <> param.lower(): if not new_ctype: new_ctype = _formatparam(p, v, requote) else: new_ctype = SEMISPACE.join([new_ctype, _formatparam(p, v, requote)]) if new_ctype <> self.get(header): del self[header] self[header] = new_ctype def set_type(self, type, header='Content-Type', requote=True): """Set the main type and subtype for the Content-Type header. type must be a string in the form "maintype/subtype", otherwise a ValueError is raised. This method replaces the Content-Type header, keeping all the parameters in place. If requote is False, this leaves the existing header's quoting as is. Otherwise, the parameters will be quoted (the default). An alternate header can be specified in the header argument. When the Content-Type header is set, we'll always also add a MIME-Version header. """ # BAW: should we be strict? if not type.count('/') == 1: raise ValueError # Set the Content-Type, you get a MIME-Version if header.lower() == 'content-type': del self['mime-version'] self['MIME-Version'] = '1.0' if not self.has_key(header): self[header] = type return params = self.get_params(header, unquote=requote) del self[header] self[header] = type # Skip the first param; it's the old type. for p, v in params[1:]: self.set_param(p, v, header, requote) def get_filename(self, failobj=None): """Return the filename associated with the payload if present. The filename is extracted from the Content-Disposition header's `filename' parameter, and it is unquoted. """ missing = [] filename = self.get_param('filename', missing, 'content-disposition') if filename is missing: return failobj if isinstance(filename, TupleType): # It's an RFC 2231 encoded parameter newvalue = _unquotevalue(filename) return unicode(newvalue[2], newvalue[0]) else: newvalue = _unquotevalue(filename.strip()) return newvalue def get_boundary(self, failobj=None): """Return the boundary associated with the payload if present. The boundary is extracted from the Content-Type header's `boundary' parameter, and it is unquoted. """ missing = [] boundary = self.get_param('boundary', missing) if boundary is missing: return failobj if isinstance(boundary, TupleType): # RFC 2231 encoded, so decode. It better end up as ascii return unicode(boundary[2], boundary[0]).encode('us-ascii') return _unquotevalue(boundary.strip()) def set_boundary(self, boundary): """Set the boundary parameter in Content-Type to 'boundary'. This is subtly different than deleting the Content-Type header and adding a new one with a new boundary parameter via add_header(). The main difference is that using the set_boundary() method preserves the order of the Content-Type header in the original message. HeaderParseError is raised if the message has no Content-Type header. """ missing = [] params = self._get_params_preserve(missing, 'content-type') if params is missing: # There was no Content-Type header, and we don't know what type # to set it to, so raise an exception. raise Errors.HeaderParseError, 'No Content-Type header found' newparams = [] foundp = False for pk, pv in params: if pk.lower() == 'boundary': newparams.append(('boundary', '"%s"' % boundary)) foundp = True else: newparams.append((pk, pv)) if not foundp: # The original Content-Type header had no boundary attribute. # Tack one one the end. BAW: should we raise an exception # instead??? newparams.append(('boundary', '"%s"' % boundary)) # Replace the existing Content-Type header with the new value newheaders = [] for h, v in self._headers: if h.lower() == 'content-type': parts = [] for k, v in newparams: if v == '': parts.append(k) else: parts.append('%s=%s' % (k, v)) newheaders.append((h, SEMISPACE.join(parts))) else: newheaders.append((h, v)) self._headers = newheaders try: from email._compat22 import walk except SyntaxError: # Must be using Python 2.1 from email._compat21 import walk def get_content_charset(self, failobj=None): """Return the charset parameter of the Content-Type header. If there is no Content-Type header, or if that header has no charset parameter, failobj is returned. """ missing = [] charset = self.get_param('charset', missing) if charset is missing: return failobj if isinstance(charset, TupleType): # RFC 2231 encoded, so decode it, and it better end up as ascii. return unicode(charset[2], charset[0]).encode('us-ascii') return charset def get_charsets(self, failobj=None): """Return a list containing the charset(s) used in this message. The returned list of items describes the Content-Type headers' charset parameter for this message and all the subparts in its payload. Each item will either be a string (the value of the charset parameter in the Content-Type header of that part) or the value of the 'failobj' parameter (defaults to None), if the part does not have a main MIME type of "text", or the charset is not defined. The list will contain one string for each part of the message, plus one for the container message (i.e. self), so that a non-multipart message will still return a list of length 1. """ return [part.get_content_charset(failobj) for part in self.walk()]