使用 Novell LDAP 对 .NET Core 中的 AD 进行页面 LDAP 查询

Question

我正在使用 Novell LDAP 库从 .NET 代码应用程序查询 Active Directory。大多数查询都会成功，但有些会返回 1000 多个结果，AD 服务器拒绝了这些结果。因此，我试图找出如何使用 Novell 的库对 LDAP 查询进行分页。我放在一起的解决方案看起来像

public IEnumerable<LdapUser> GetUsers() {
    this.Connect();

    try {
        var cntRead = 0;                            // Total users read.
        int? cntTotal = null;                       // Users available.
        var curPage = 0;                            // Current page.
        var pageSize = this._config.LdapPageSize;   // Users per page.

        this.Bind();

        this._logger.LogInformation("Searching LDAP users.");
        do {
            var constraints = new LdapSearchConstraints();

            // The following has no effect:
            //constraints.MaxResults = 10000;

            // Commenting out the following succeeds until the 1000th entry.
            constraints.setControls(GetListControl(curPage, pageSize));

            var results = this._connection.Search(
                this._config.LdapSearchBase,
                this.LdapSearchScope,
                this._config.LdapUsersFilter,
                this.LdapUserProperties,
                false,
                constraints);

            while (results.hasMore() && ((cntTotal == null) || (cntRead < cntTotal))) {
                ++cntRead;

                LdapUser user = null;

                try {
                    var result = results.next();
                    Debug.WriteLine($"Found user {result.DN}.");
                    user = new LdapUser() {
                        AccountName = result.getAttribute(this._config.LdapAccountAttribute)?.StringValue,
                        DisplayName = result.getAttribute(this._config.LdapDisplayNameAttribute)?.StringValue
                    };
                } catch (LdapReferralException) {
                    continue;
                }

                yield return user;
            }

            ++curPage;
            cntTotal = GetTotalCount(results);
        } while ((cntTotal != null) && (cntRead < cntTotal));
    } finally {
        this._connection.Disconnect();
    }
}

并使用以下两个辅助方法：

private static LdapControl GetListControl(int page, int pageSize) {
    Debug.Assert(page >= 0);
    Debug.Assert(pageSize >= 0);
    var index = page * pageSize + 1;
    var before = 0;
    var after = pageSize - 1;
    var count = 0;
    Debug.WriteLine($"LdapVirtualListControl({index}, {before}, {after}, {count}) = {before}:{after}:{index}:{count}");
    return new LdapVirtualListControl(index, before, after, count);
}

private static int? GetTotalCount(LdapSearchResults results) {
    Debug.Assert(results != null);

    if (results.ResponseControls != null) {
        var r = (from c in results.ResponseControls
                 let d = c as LdapVirtualListResponse
                 where (d != null)
                 select (LdapVirtualListResponse) c).SingleOrDefault();
        if (r != null) {
            return r.ContentCount;
        }
    }

    return null;
}   

设置constraints.MaxResults似乎对 AD 服务器没有影响。如果我不设置LdapVirtualListControl，则检索成功，直到检索到第 1000 个条目。

如果我使用LdapVirtualListControl，则操作在第一次调用时失败，但results.next()有以下异常：

System.Collections.Generic.KeyNotFoundException: The given key '76' was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Novell.Directory.Ldap.Utilclass.ResourcesHandler.getResultString(Int32 code, CultureInfo locale)
   at Novell.Directory.Ldap.LdapResponse.get_ResultException()
   at Novell.Directory.Ldap.LdapResponse.chkResultCode()
   at Novell.Directory.Ldap.LdapSearchResults.next()

https://github.com/dsbenghe/Novell.Directory.Ldap.NETStandard/blob/master/src/Novell.Directory.Ldap.NETStandard/Utilclass/ResultCodeMessages.cs 上的代码表明这只是一个后续错误真正的问题是调用失败，错误代码为 76，我不知道它是什么。因此，我认为我在查询中遗漏了一些东西。有什么问题吗？

Answer 1

我修复了它 - 以防其他人遇到这个：

经过一些互联网研究，我在https://ldap.com/ldap-result-code-reference-other-server-side-result-codes/#rc-virtualListViewError 上发现错误代码 76 意味着什么，其中LdapVirtualListResponse包含更多信息。就我而言，错误是https://ldap.com/ldap-result-code-reference-other-server-side-result-codes/#rc-sortControlMissing - 所以似乎分页需要排序控制。为了修复它，我添加了

constraints.setControls(new[] {
    new LdapSortControl(new LdapSortKey("cn"), true),
    GetListControl(curPage, pageSize)
});