Crossplattform way to check active directory in ASP.NET Core 6

Question

I want to read data from an Active Directory within an ASP.NET Core 6 app. I know how this can be achieved with a DirectorySearcher:

var entry = new DirectoryEntry(GlobalConfig.Configuration.LDAP, Input.Username, Input.Password);

try
{
    var _object = entry.NativeObject;
    DirectorySearcher searcher = new DirectorySearcher(entry);
    searcher.Filter = $"(SAMAccountName={Input.Username})";
    searcher.PropertiesToLoad.Add("cn");
    searcher.PropertiesToLoad.Add("memberOf");
    searcher.PropertiesToLoad.Add("employeeid");
    searcher.PropertiesToLoad.Add("telephonenumber");
    searcher.PropertiesToLoad.Add("displayName");
    searcher.PropertiesToLoad.Add("mail");

    SearchResult result = searcher.FindOne();
catch(Excepetion ex)
{
    // ...
}

However, this solution does only work when we host the app within a windows environment. Is there any way to check this data with a cross plattform approach?

Answer 1

You can use System.DirectoryServices.Protocols package and specifically the LdapConnection class.

Example:

using System.DirectoryServices.Protocols;
...

try
{
    using var connection = new LdapConnection("{server}");

    var networkCredential = new NetworkCredential(Input.Username, Input.Password, "{domain}");
    connection.SessionOptions.SecureSocketLayer = false;
    connection.AuthType = AuthType.Negotiate;
    connection.Bind(networkCredential);

    var searchRequest = new SearchRequest(
        "{distinguishedName}",
        $"(SAMAccountName={Input.Username})",
        SearchScope.OneLevel,
        new string[]
        {
            "cn",
            "memberOf",
            "employeeid",
            "telephonenumber",
            "displayName",
            "mail"
        });

    SearchResponse directoryResponse = (SearchResponse)connection.SendRequest(searchRequest);

    SearchResultEntry searchResultEntry = directoryResponse.Entries[0];
    // ...
}
catch (LdapException ex)
{
    // ...
}

Modify connection and search options accordingly. You can find documentation here. You might get warning for LdapSessionOptions.SecureSocketLayer that it is only supported on Windows but this is a false warning that you can ignore.