Add option to strip images from emails

README.md

@@ -87,7 +87,7 @@ The following configuration options are optional in each quarantine section:
   * **{EMAIL_QUARANTINE_ID}**  
     Quarantine-ID of the original e-mail if available, empty otherwise.
   * **{EMAIL_HTML_TEXT}**  
-    Sanitized version of the e-mail text part of the original e-mail. Only harmless HTML tags and attributes are included. Images are replaced with the image set by notification_email_replacement_img option.
+    Sanitized version of the e-mail text part of the original e-mail. Only harmless HTML tags and attributes are included. Images are optionally stripped or replaced with the image set by notification_email_replacement_img option.
 
   Some template variables are only available if the regex of the matching quarantine contains subgroups or named subgroups (python syntax). This is useful to include information (e.g. virus names, spam points, ...) of the matching header within the notification.  
   The following dynamic template variables are available:
@@ -105,12 +105,17 @@ The following configuration options are optional in each quarantine section:
     Notification e-mail subject. All e-mail template variable described above is usable.
   * **notification_email_template**  
     Path to the notification e-mail template. It is hold in memory during runtime.
-  * **notification_email_replacement_img**  
-    Path to the image to replace images in e-mails. It is hold in memory during runtime. Leave it empty to disable.
   * **notification_email_embedded_imgs**  
     Comma-separated list of images to embed into the notification e-mail. The Content-ID of each image will be set to the filename, so you can reference it from the e-mail template. All images are hold in memory during runtime.  
     Leave empty to disable.
 
+The following configuration options are optional for this notification type:
+  * **notification_email_strip_images**  
+    Enable to strip images from e-mails. This option superseeds notification_email_replacement_img.
+  * **notification_email_replacement_img**  
+    Path to an image to replace images in e-mails. It is hold in memory during runtime.
+
+
 ### Actions
 Every quarantine responds with a milter-action if an e-mail header matches the configured regular expression. Please think carefully what you set here or your MTA will do something you do not want.  
 The following actions are available:

docs/pyquarantine.conf.example

@@ -117,10 +117,15 @@ notification_email_subject = Spam Quarantine Notification
 #
 notification_email_template = templates/notification.template
 
+# Option: notification_email_strip_images
+# Notes:  Optionally enable this option to strip img tags from emails.
+# Values: [ TRUE|ON|YES|FALSE|OFF|NO ]
+#
+notification_email_strip_images = False
+
 # Option: notification_email_replacement_img
-# Notes:  Set the path to the replacement image for img tags within emails.
+# Notes:  Optionally set the path to a replacement image for img tags within emails.
 #         A relative path to this config file can be used.
-#         This option is needed by notification type 'email'.
 # Values: [ IMAGE_PATH ]
 #
 notification_email_replacement_img = templates/removed.png

pyquarantine/notifications.py

@@ -119,7 +119,6 @@ class EMailNotification(BaseNotification):
             "notification_email_from",
             "notification_email_subject",
             "notification_email_template",
-            "notification_email_replacement_img",
                 "notification_email_embedded_imgs"]:
             if option not in self.config.keys() and option in self.global_config.keys():
                 self.config[option] = self.global_config[option]
@@ -128,6 +127,18 @@ class EMailNotification(BaseNotification):
                     "mandatory option '{}' not present in config section '{}' or 'global'".format(
                         option, self.quarantine_name))
 
+        # check if optional config options are present in config
+        defaults = {
+            "notification_email_replacement_img": "",
+            "notification_email_strip_images": "false"
+        }
+        for option in defaults.keys():
+            if option not in config.keys() and \
+                    option in global_config.keys():
+                config[option] = global_config[option]
+            if option not in config.keys():
+                config[option] = defaults[option]
+
         self.smtp_host = self.config["smtp_host"]
         self.smtp_port = self.config["smtp_port"]
         self.mailfrom = self.config["notification_email_envelope_from"]
@@ -160,13 +171,20 @@ class EMailNotification(BaseNotification):
         except ValueError as e:
             raise RuntimeError("error parsing template: {}".format(e))
 
+        strip_images = self.config["notification_email_strip_images"].strip().upper()
+        if strip_images in ["TRUE", "ON", "YES"]:
+            self.strip_images = True
+        elif strip_images in ["FALSE", "OFF", "NO"]:
+            self.strip_images = False
+        else:
+            raise RuntimeError("error parsing notification_email_strip_images: unknown value")
+
         # read email replacement image if specified
-        replacement_img_path = self.config["notification_email_replacement_img"].strip(
+        replacement_img = self.config["notification_email_replacement_img"].strip()
-        )
+        if not strip_images and replacement_img:
-        if replacement_img_path:
             try:
                 self.replacement_img = MIMEImage(
-                    open(replacement_img_path, "rb").read())
+                    open(replacement_img, "rb").read())
             except IOError as e:
                 raise RuntimeError(
                     "error reading replacement image: {}".format(e))
@@ -307,7 +325,14 @@ class EMailNotification(BaseNotification):
 
         # replace picture sources
         image_replaced = False
-        if self.replacement_img:
+        if self.strip_images:
+            for element in soup("img"):
+                if "src" in element.attrs.keys():
+                    self.logger.debug(
+                        "{}: removing image: {}".format(
+                            queueid, element["src"]))
+                element.extract()
+        elif self.replacement_img:
             for element in soup("img"):
                 if "src" in element.attrs.keys():
                     self.logger.debug(