Documentation and usage example for sieve script

packages/alias-to-sieve/Cargo.toml

@@ -4,6 +4,10 @@ version = "0.1.0"
 edition = "2021"
 
 rust-version = "1.68.2"
+description = "Convert an alias file to a sieve script for stalwart-mail"
+readme = "README.md"
+license = " AGPL-3.0-only"
+keywords = ["mail", "sieve", "alias", "stalwart"]
 
 [dependencies]
 fqdn = {version = "0.4.2", features = ["domain-label-length-limited-to-63", "domain-name-without-special-chars"]}

packages/alias-to-sieve/README.md

@@ -0,0 +1,64 @@
+This script converts an alias file to a sieve script for [stalwart-mail](https://stalw.art/).
+
+## Usage
+Given an alias file `testdata/simple.aliases` that contains lines of redirects of the form localpart with optional `@fqdn` followed by a space followed by a list (space or comma+space separated) list of destinations that consist of a localpart and optionally an `@fqdn`.
+If you don't define a fqdn along any of the addresses, the default domain from your commandline input will be appended.
+
+An example using the testdata directory of this repository:
+```bash
+$ ./alias_to_sieve testdata/simple.aliases example.com
+```
+```sieve
+require ["variables", "copy", "vnd.stalwart.expressions", "envelope", "editheader"];
+
+let "i" "0";
+while "i < count(envelope.to)" {
+  let "redirected" "false";
+  if eval "eq_ignore_case(envelope.to[i], 'admin@example.com')" {
+    addheader "Delivered-To" "admin@example.com";
+    redirect :copy "me@example.org";
+
+    deleteheader :index 1 :is "Delivered-To" "admin@example.com";
+    let "redirected" "true";
+  }
+  if eval "eq_ignore_case(envelope.to[i], 'postmaster@example.com')" {
+    addheader "Delivered-To" "postmaster@example.com";
+    redirect :copy "me@example.org";
+
+    deleteheader :index 1 :is "Delivered-To" "postmaster@example.com";
+    let "redirected" "true";
+  }
+  if eval "eq_ignore_case(envelope.to[i], 'root@example.com')" {
+    addheader "Delivered-To" "root@example.com";
+    redirect :copy "me@example.org";
+
+    deleteheader :index 1 :is "Delivered-To" "root@example.com";
+    let "redirected" "true";
+  }
+  if eval "eq_ignore_case(envelope.to[i], 'sudo@example.com')" {
+    addheader "Delivered-To" "sudo@example.com";
+    redirect :copy "me@example.org";
+
+    deleteheader :index 1 :is "Delivered-To" "sudo@example.com";
+    let "redirected" "true";
+  }
+  if eval "!redirected" {
+    let "destination" "envelope.to[i]";
+    redirect :copy "${destination}";
+  }
+  let "i" "i+1";
+}
+discard;
+
+```
+
+If you have multiple domains with multiple alias files, pass them all in one run: `$ ./alias_to_sieve simple.aliases example.com other.aliases example.org`.
+
+## Limitations
+You cannot use apostrophes (') in any mail addresses although allowed by [RFC 5322](https://www.rfc-editor.org/rfc/rfc5322) since they would break termination of strings in sieve.
+
+This parser is not designed with security in mind. While the above gives some basic protection against code injection, I have no idea whether sieve has other pitfalls that might allow them.
+
+This is my first rust project, consume the code with care.
+
+The generated code is specific to stalwart-mail and contains non-standard sieve features.