18.13.1 SMTP Objects
An SMTP instance has the following methods:
- Set the debug output level. A true value for level results in debug messages for connection and for all messages sent to and received from the server.
- Connect to a host on a given port. The defaults are to connect to the local host at the standard SMTP port (25). If the hostname ends with a colon (":") followed by a number, that suffix will be stripped off and the number interpreted as the port number to use. This method is automatically invoked by the constructor if a host is specified during instantiation.
-
Send a command cmd to the server. The optional argument
argstring is simply concatenated to the command, separated by a
space.
This returns a 2-tuple composed of a numeric response code and the actual response line (multiline responses are joined into one long line.)
In normal operation it should not be necessary to call this method explicitly. It is used to implement other methods and may be useful for testing private extensions.
If the connection to the server is lost while waiting for the reply, SMTPServerDisconnected will be raised.
-
Identify yourself to the SMTP server using "HELO". The hostname
argument defaults to the fully qualified domain name of the local
host.
In normal operation it should not be necessary to call this method explicitly. It will be implicitly called by the sendmail() when necessary.
-
Identify yourself to an ESMTP server using "EHLO". The hostname
argument defaults to the fully qualified domain name of the local
host. Examine the response for ESMTP option and store them for use by
has_extn().
Unless you wish to use has_extn() before sending mail, it should not be necessary to call this method explicitly. It will be implicitly called by sendmail() when necessary.
- Return True if name is in the set of SMTP service extensions returned by the server, False otherwise. Case is ignored.
-
Check the validity of an address on this server using SMTP "VRFY".
Returns a tuple consisting of code 250 and a full RFC 822 address
(including human name) if the user address is valid. Otherwise returns
an SMTP error code of 400 or greater and an error string.
Note: Many sites disable SMTP "VRFY" in order to foil spammers.
-
Log in on an SMTP server that requires authentication.
The arguments are the username and the password to authenticate with.
If there has been no previous "EHLO" or "HELO" command this
session, this method tries ESMTP "EHLO" first.
This method will return normally if the authentication was successful,
or may raise the following exceptions:
- The server didn't reply properly to the "HELO" greeting.
- The server didn't accept the username/password combination.
- No suitable authentication method was found.
-
Put the SMTP connection in TLS (Transport Layer Security) mode. All
SMTP commands that follow will be encrypted. You should then call
ehlo() again.
If keyfile and certfile are provided, these are passed to the socket module's ssl() function.
-
Send mail. The required arguments are an RFC 822 from-address
string, a list of RFC 822 to-address strings (a bare string will be
treated as a list with 1 address), and a message string. The caller
may pass a list of ESMTP options (such as "8bitmime") to be used
in "MAIL FROM" commands as mail_options. ESMTP options
(such as "DSN" commands) that should be used with all "RCPT"commands can be passed as rcpt_options. (If you need to use
different ESMTP options to different recipients you have to use the
low-level methods such as mail, rcpt and
data to send the message.)
Note: The from_addr and to_addrs parameters are used to construct the message envelope used by the transport agents. The SMTP does not modify the message headers in any way.
If there has been no previous "EHLO" or "HELO" command this session, this method tries ESMTP "EHLO" first. If the server does ESMTP, message size and each of the specified options will be passed to it (if the option is in the feature set the server advertises). If "EHLO" fails, "HELO" will be tried and ESMTP options suppressed.
This method will return normally if the mail is accepted for at least one recipient. Otherwise it will throw an exception. That is, if this method does not throw an exception, then someone should get your mail. If this method does not throw an exception, it returns a dictionary, with one entry for each recipient that was refused. Each entry contains a tuple of the SMTP error code and the accompanying error message sent by the server.
This method may raise the following exceptions:
- All recipients were refused. Nobody got the mail. The
recipients attribute of the exception object is a dictionary
with information about the refused recipients (like the one returned
when at least one recipient was accepted).
- The server didn't reply properly to the "HELO" greeting.
- The server didn't accept the from_addr.
- The server replied with an unexpected error code (other than a refusal of a recipient).
Unless otherwise noted, the connection will be open even after an exception is raised.
- All recipients were refused. Nobody got the mail. The
recipients attribute of the exception object is a dictionary
with information about the refused recipients (like the one returned
when at least one recipient was accepted).
- Terminate the SMTP session and close the connection.
Low-level methods corresponding to the standard SMTP/ESMTP commands "HELP", "RSET", "NOOP", "MAIL", "RCPT", and "DATA" are also supported. Normally these do not need to be called directly, so they are not documented here. For details, consult the module code.
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