SieveFiler is a Swift-based DSL to aid in creating Sieve (RFC 5228) "fileinto" rules for server-side mail sorting. The primary goal is to make it easier and less error-prone to creating rules for filing mail into specific folders.

SieveFiler will:

• Ensure generated sieve rules are ordered from specific to general
• Ensure full email addresses are given for Addresses()
• Ensure only domain names are given for Domains() and SubDomains()
• Ensure conflicting rules are not possible (e.g. cannot specify that the same email address goes to different folders)
• Not overwrite the file if any errors are detected
• SubDomains() matcher makes it easy to specify rules to match either "@domain.xyz" or "*.domain.xyz".

Swift Compiler 5.7+. By utilizing the Swift language, you can use Xcode or any other IDE/text editor to aid in command completion and online help as you write your rules.

The simplest usage is to install swift-sh:

mint install swift-sh

Then create your Sieve script like so:

#!/usr/bin/swift sh
import SieveFiler // @dannys42
import Foundation

try SieveRules {
    Folder("Family") {
        Fields(.from) {
            Domains("myfamily.xyz")  // matches exactly the addresses given
        }
    }
    Folder("Parents") {
        Fields(.from) {
            Addresses("[email protected]", "[email protected]")  // matches exactly the addresses given
        }
    }
    Folder("Classmates") {
        Fields(.from, .replyTo) {
            Domains("myschoolalumnis.edu")  // matches exactly emails that have `myschoolalumnis.edu` after the "@" sign
            SubDomains("myschool.edu")      // matches *.myschool.edu and @myschool.edu
        }
    }
}.output(".dovecot.sieve")

This will create rules in the following order:

• Mail from [email protected] and [email protected] will go into Parents
• Mail from anyone else in the myfamily.xyz domain will go to Family
• Any mail with a From or Reply-To field with a domain of exactly myschoolalumnis.edu will go into Classmates
• Any mail with a From or Reply-To field with a domain or any subdomain of myschool.edu will also go into Classmates

Additional conveniences:

• Domains, SubDomains, and Addresses can also take array arguments to allow for flexibility in trailing commas. For example:

    Folder("Parents") {
        Fields(.from) {
            Addresses([
            	"[email protected]",
            	"[email protected]",
            ])
        }
    }

• In cases where only one type of Fields matching is needed, you can specify that field on the Folder() line. For example:

    Folder("Parents", fields: .from) {
        Addresses([
            "[email protected]",
            "[email protected]",
        ])
    }