Fix parsing of displayName

Currently, we only have one field for the name. The first part is
first name. The rest is last name. Obviously, this won't work in all
cases but is the best we can do for the moment.

src/ldapserver.js

@@ -161,10 +161,9 @@ async function userSearch(req, res, next) {
         const dn = ldap.parseDN('cn=' + user.id + ',ou=users,dc=cloudron');
 
         const displayName = user.displayName || user.username || ''; // displayName can be empty and username can be null
-        const nameParts = displayName.split(' ');
-        const firstName = nameParts[0];
-        const lastName = nameParts.length > 1  ? nameParts[nameParts.length - 1] : ''; // choose last part, if it exists
+        const { firstName, lastName, middleName } = users.parseDisplayName(displayName);
 
+        // https://datatracker.ietf.org/doc/html/rfc2798
         const obj = {
             dn: dn.toString(),
             attributes: {
@@ -177,17 +176,14 @@ async function userSearch(req, res, next) {
                 mailAlternateAddress: user.fallbackEmail,
                 displayname: displayName,
                 givenName: firstName,
+                sn: lastName,
+                middleName: middleName,
                 username: user.username,
                 samaccountname: user.username,      // to support ActiveDirectory clients
                 memberof: allGroups.filter(function (g) { return g.userIds.indexOf(user.id) !== -1; }).map(function (g) { return `cn=${g.name},ou=groups,dc=cloudron`; })
             }
         };
 
-        // http://www.zytrax.com/books/ldap/ape/core-schema.html#sn has 'name' as SUP which is a DirectoryString
-        // which is required to have atleast one character if present
-        if (lastName.length !== 0) obj.attributes.sn = lastName;
-
-        // ensure all filter values are also lowercase
         const lowerCaseFilter = safe(function () { return ldap.parseFilter(req.filter.toString().toLowerCase()); }, null);
         if (!lowerCaseFilter) return next(new ldap.OperationsError(safe.error.message));