django.core.mail.SMTPConnection.open() method performs an unnecessary call to socket.getfqdn()

[George Murdocca <gmurdocca@…>]

Summary

This is an optimization fix as opposed to a bug. The django.core.mail.SMTPConnection.open() method performs an extraneous call to socket.getfqdn() which affects performance. The mail.py module has a class defined called CachedDnsName() whos get_fqdn() method addresses this issue by calling socket.getfqdn(), and caches the result, thus removing the need to call it again later. The fix is extremely trivial to implement. Here are the details:

Detailed Description

On line 122 of the mail.py module, an smtplib.SMTP() object is instantiated:

self.connection = smtplib.SMTP(self.host, self.port)

The constructor of smtplib.SMTP() accepts three arguments, namely host='', port=0, local_hostname=None. However, local_hostname is omitted in mail.py. When omitted, socket.getfqdn() is called, and its value is assigned to the missing argument. This call is extraneous and slow, because:

• socket.getfqdn() is slow to evaluate (as mentioned in the comment at line 28 of mail.py)
• The result of socket.getfqdn() already done once and cached by django.core.mail.CachedDnsName.get_fqdn(), and shoul dbe used instead.

The Fix

Change line 122 of mail.py to:

self.connection = smtplib.SMTP(self.host, self.port, local_hostname=DNS_NAME.get_fqdn())

The Diff

--- mail.py     2008-03-02 12:45:20.000000000 +1100
+++ mailjrj.py  2008-03-20 14:04:07.000000000 +1100
@@ -119,7 +119,7 @@
             # Nothing to do if the connection is already open.
             return False
         try:
-            self.connection = smtplib.SMTP(self.host, self.port)
+            self.connection = smtplib.SMTP(self.host, self.port, local_hostname=DNS_NAME.get_fqdn())
             if self.use_tls:
                 self.connection.ehlo()
                 self.connection.starttls()

Cheers,
George Murdocca & Phil Wright.

[Philippe Raoult]

proper patch against SVN

[Philippe Raoult]

applies to SVN, and successfully tested on my app.

[Gary Wilson]

(In [7348]) Fixed #6835 -- Use cached FQDN when creating smtplib.SMTP() connection to avoid a lengthy
socket.getfqdn() call, thanks George Murdocca and PhiR.