ported MailSender class to use twisted non-blocking IO

--HG--
extra : convert_revision : svn%3Ab85faa78-f9eb-468e-a121-7cced6da292c%40708

scrapy/trunk/docs/ref/email.rst

@@ -7,13 +7,14 @@ Sending email
 .. module:: scrapy.mail
    :synopsis: Helpers to easily send e-mail.
 
-Although Python makes sending e-mail relatively easy via the `smtplib library`_,
-Scrapy provides a couple of light wrappers over it, to make sending e-mail
-extra quick.
+Although Python makes sending e-mail relatively easy via the `smtplib`_
+library, Scrapy provides its own class for sending emails which is very easy to
+use and it's implemented using `Twisted non-blocking IO`_, to avoid affecting
+the crawling performance.
 
-The code lives in a single module: ``scrapy.mail``.
+.. _smtplib: http://docs.python.org/library/smtplib.html
 
-.. _smtplib library: http://docs.python.org/library/smtplib.html
+It also has built-in support for sending attachments.
 
 Quick example
 =============
@@ -25,14 +26,11 @@ Here's a quick example of how to send an email (without attachments)::
     mailer = MailSender()
     mailer.send(to=["someone@example.com"], "Some subject", "Some body", cc=["another@example.com"])
 
-MailSender class
-================
+MailSender class reference
+==========================
 
-MailSender is the class used to send emails from Scrapy. It's
-currently only a wrapper over the (IO blocking) `smtplib`_
-library but it's gonna be ported to Twisted soon.
-
-.. _smtplib: http://docs.python.org/library/smtplib.html
+MailSender is the preferred class to use for sending emails from Scrapy, as it
+uses `Twisted non-blocking IO`_, like the rest of the framework. 
 
 .. class:: scrapy.mail.MailSender(smtphost, mailfrom)
 
@@ -42,7 +40,7 @@ library but it's gonna be ported to Twisted soon.
     ``mailfrom`` is a string with the email address to use for sending messages
     (in the ``From:`` header). If omitted, :setting:`MAIL_FROM` will be used.
 
-.. method:: send(to, subject, body, cc=None, attachs=None)
+.. method:: send(to, subject, body, cc=None, attachs=())
 
     Send mail to the given recipients
         
@@ -59,3 +57,5 @@ library but it's gonna be ported to Twisted soon.
         ``mimetype`` is the mimetype of the attachment
         ``file_object`` is a readable file object
 
+
+.. _Twisted non-blocking IO: http://twistedmatrix.com/projects/core/documentation/howto/async.html

scrapy/trunk/scrapy/mail/__init__.py

@@ -3,14 +3,17 @@ Mail sending helpers
 
 See documentation in docs/ref/email.rst
 """
-import smtplib
-
+from cStringIO import StringIO
 from email.MIMEMultipart import MIMEMultipart
+from email.MIMENonMultipart import MIMENonMultipart
 from email.MIMEBase import MIMEBase
 from email.MIMEText import MIMEText
 from email.Utils import COMMASPACE, formatdate
 from email import Encoders
 
+from twisted.internet import defer, reactor
+from twisted.mail.smtp import SMTPSenderFactory
+
 from scrapy import log
 from scrapy.core.exceptions import NotConfigured
 from scrapy.conf import settings
@@ -24,8 +27,11 @@ class MailSender(object):
         if not self.smtphost or not self.mailfrom:
             raise NotConfigured("MAIL_HOST and MAIL_FROM settings are required")
 
-    def send(self, to, subject, body, cc=None, attachs=None):
-        msg = MIMEMultipart()
+    def send(self, to, subject, body, cc=None, attachs=()):
+        if attachs:
+            msg = MIMEMultipart()
+        else:
+            msg = MIMENonMultipart('text', 'plain')
         msg['From'] = self.mailfrom
         msg['To'] = COMMASPACE.join(to)
         msg['Date'] = formatdate(localtime=True)
@@ -35,17 +41,36 @@ class MailSender(object):
             rcpts.extend(cc)
             msg['Cc'] = COMMASPACE.join(cc)
 
-        msg.attach(MIMEText(body))
+        if attachs:
+            msg.attach(MIMEText(body))
+            for attach_name, mimetype, f in attachs:
+                part = MIMEBase(*mimetype.split('/'))
+                part.set_payload(f.read())
+                Encoders.encode_base64(part)
+                part.add_header('Content-Disposition', 'attachment; filename="%s"' % attach_name)
+                msg.attach(part)
+        else:
+            msg.set_payload(body)
 
-        for attach_name, mimetype, f in (attachs or []):
-            part = MIMEBase(*mimetype.split('/'))
-            part.set_payload(f.read())
-            Encoders.encode_base64(part)
-            part.add_header('Content-Disposition', 'attachment; filename="%s"' % attach_name)
-            msg.attach(part)
+        dfd = self._sendmail(self.smtphost, self.mailfrom, rcpts, msg.as_string())
+        dfd.addCallbacks(self._sent_ok, self._sent_failed,
+            callbackArgs=[to, cc, subject, len(attachs)],
+            errbackArgs=[to, cc, subject, len(attachs)])
 
-        smtp = smtplib.SMTP(self.smtphost)
-        smtp.sendmail(self.mailfrom, rcpts, msg.as_string())
-        log.msg('Mail sent: To=%s Cc=%s Subject="%s"' % (to, cc, subject))
-        smtp.close()
+    def _sent_ok(self, result, to, cc, subject, nattachs):
+        log.msg('Mail sent OK: To=%s Cc=%s Subject="%s" Attachs=%d' % (to, cc, subject, nattachs))
+
+    def _sent_failed(self, failure, to, cc, subject, nattachs):
+        errstr = str(failure.value)
+        log.msg('Unable to send mail: To=%s Cc=%s Subject="%s" Attachs=%d - %s' % (to, cc, subject, nattachs, errstr), level=log.ERROR)
+
+    def _sendmail(self, smtphost, from_addr, to_addrs, msg, port=25):
+        """ This is based on twisted.mail.smtp.sendmail except that it
+        instantiates a quiet (noisy=False) SMTPSenderFactory """
+        msg = StringIO(msg)
+        d = defer.Deferred()
+        factory = SMTPSenderFactory(from_addr, to_addrs, msg, d)
+        factory.noisy = False
+        reactor.connectTCP(smtphost, port, factory)
+        return d