Advanced Scripting (Professional and Enterprise Editions only)

Scripted filtering provides a flexible and extensible means of creating complex filters. The scripting language used is similar to Microsoft VBScript and includes an in-built function for validating criteria. The variable called FilterResult is used as the return value from the filter and can be set at any time in the script. A FilterResult value of 0 indicates that the filter criteria were not met while a value of 1 indicates that the filter criteria were met, and the associated actions for the filter will be executed. Criteria within scripts can be formed using literal values or tests. Literal values are tokens that are placed in the script and are substituted with their corresponding value. For example, a literal value of [ME_SIZE] can be placed directly in the script for comparison and will be substituted with the message size when the filter is executed. Tests are performed using the CriteriaMet function, and is used for non-numeric values, such as when string comparisons are being made.

Literal values

Token	Value
[ME_SPAM_PROBABILITY]	Contains a numeric value of the calculated Bayesian probability of a message being detected as spam.
[ME_SIZE]	The size of the message in bytes
[ME_SENDERAUTH]	Indicates whether the sender of the message authenticated in order to dispatch the message to MailEnable. The value is 1 if the sender authenticated, otherwise the value is 0.
[ME_HASVIRUS]	Indicates whether the message contained a virus. The value is 1 if the message contained a virus, otherwise the value is 0. When a virus is detected by filter criteria it is automatically removed from the message.
[ME_HASANATTACHMENT]	Indicates whether the message has an attachment. The value is 1 if the message has an attachment, otherwise the value is 0.

Literal enumeration example:

If ([ME_SENDERAUTH] = 0) Then
‘sender has not authenticated
End If

Extra literal values are also available for substitution. These are formatted differently because they are not evaluated as the filter is being executed, but read from the command file for the message being processed.

Token	Value
%IPADDRESS%	The TCP/IP address of the originating message
%POSTOFFICE%	The post office that can reasonably be assigned to the message.
%SENDER%	The sender of the message in Internal format of [CONNECTOR:Address]. E.g. [SMTP:xjz@mailenable.com]
%RECIPIENTS%	The recipient(s) of the message in internal format of [CONNECTOR:Address];[CONNECTOR:Address2]. E.g. [SMTP:xjz@mailenable.com];[SMTP:def@mailenable.com]
%SUBJECT%	The subject of the message.

Enumerations requiring the CriteriaMet syntax

Literal Enumeration example:
If (CriteriaMet([ME_SUBJECT], "Viagra")) Then
'Do Stuff
End If

In cases where literal values return 1 or 0, it is possible to also use literal values with the CriteriaMet function, although there is no real reason to do so:

Example: CriteriaMet([ME_SENDERAUTH], 0) is the same as
([ME_SENDERAUTH] = 0)
But this is not the case for string values:
CriteriaMet([ME_SUBJECT], "Viagra") is not the same as
([ME_SUBJECT] = "Viagra") because string tokens cannot be used in this manner.

Basic script example

An example script for an advanced filter is outlined below:

This example script will have its criteria met under the following circumstances. If it is after the 10th hour of the day and the size of the message is greater than 1KB Or the Body of the message contains the string 123.

Advanced script example

A more complicated example script for a filter is outlined below:

This script is similar to the one above, with the exception of containing more comparisons.

Note: In the above example, the CriteriaMet([ME_SIZE],123) line actually implicitly means that the message size is greater than 123 bytes.

Reporting Matching Criteria

MailEnable logs a return result from filters to the log file or as the [ME_CRITERIA] token replacement for actions. For example, the action to add a header to an email can use the [ME_CRITERIA] token which will be replaced with the string returned from the script. When not using scripting for a filter, this return value is preset and cannot be modified, but when a scripting filter is used the return value can be set within the script.  This is done by setting the MEResultData variable within the script.

If not using a scripted filter, then a system-generated string is returned to denote which were the matching criteria. An example string returned when a filter is matching the term 'Viagra' at the beginning of the message subject follows:

CRITERIA=SUBJECT, DATA=<MF-W>Viagra*</MF-W>

An extract from an example log file is shown below. The filter column will show whether a scripted filter is being used or not.

This example shows messages A.MAI and B.MAI being processed.

A.MAI was intercepted by a filter called "Scripted" because the scripted filter reported that the subject matched the term ABC.

B.MAI was intercepted by a filter called "Basic" because the Subject of the message matched a criteria string AB*. (Note: the <MF-W> mark-up around the term is used to indicate that the term was sourced from word list criteria).