mail: resolve list members

src/mail.js

@@ -46,6 +46,7 @@ exports = module.exports = {
     addList: addList,
     updateList: updateList,
     removeList: removeList,
+    resolveList: resolveList,
 
     _readDkimPublicKeySync: readDkimPublicKeySync
 };
@@ -1268,3 +1269,50 @@ function removeList(name, domain, auditSource, callback) {
         callback();
     });
 }
+
+function resolveList(listName, listDomain, callback) {
+    assert.strictEqual(typeof listName, 'string');
+    assert.strictEqual(typeof listDomain, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    getDomains(function (error, mailDomains) {
+        if (error) return callback(error);
+
+        const mailInDomains = mailDomains.filter(function (d) { return d.enabled; }).map(function (d) { return d.domain; }).join(',');
+
+        mailboxdb.getList(listName, listDomain, function (error, list) {
+            if (error) return callback(error);
+
+            let result = [], toResolve = list.members.slice(), visited = []; // slice creates a copy of array
+
+            async.whilst(() => toResolve.length != 0, function (iteratorCallback) {
+                const toProcess = toResolve.shift();
+                const parts = toProcess.split('@');
+                const memberName = parts[0].split('+')[0], memberDomain = parts[1];
+
+                if (!mailInDomains.includes(memberDomain)) { result.push(toProcess); return iteratorCallback(); } // external domain
+
+                const member =`${memberName}@${memberDomain}`; // cleaned up without any '+' subaddress
+                if (visited.includes(member)) {
+                    debug(`resolveList: list ${listName}@${listDomain} has a recursion at member ${member}`);
+                    return iteratorCallback();
+                }
+                visited.push(member);
+
+                mailboxdb.get(memberName, memberDomain, function (error, entry) {
+                    if (error && error.reason == BoxError.NOT_FOUND) { result.push(member); return iteratorCallback(); }
+                    if (error) return iteratorCallback(error);
+
+                    if (entry.type === mailboxdb.TYPE_MAILBOX) { result.push(member); return iteratorCallback(); }
+                    // no need to resolve alias because we only allow one level and within same domain
+                    if (entry.type === mailboxdb.TYPE_ALIAS) { result.push(`${entry.aliasTarget}@${entry.domain}`); return iteratorCallback(); }
+
+                    toResolve = toResolve.concat(entry.members);
+                    iteratorCallback();
+                });
+            }, function (error) {
+                callback(error, result);
+            });
+        });
+    });
+}