为什么我的目录搜索需要这么长时间？

Question

我一直在对 REST 中的性能进行故障排除 API 我已经构建了 returns 基于提供的搜索词的 Active Directory 用户列表。根据我为测试目的而内置的一些日志记录，我可以看到获取设置（例如 LDAP 搜索信息）和检索所有搜索结果的整个过程不到一秒钟：

30/08/2017 3:37:58 PM | Getting search results.
30/08/2017 3:37:58 PM | Retrieving default settings
30/08/2017 3:37:58 PM | Default settings retrieved. Creating directoryEntry
30/08/2017 3:37:58 PM | Search retrieved.
30/08/2017 3:37:58 PM | Iterating through search results.
30/08/2017 3:38:16 PM | Search results iteration complete.

但是，如您所见，遍历这些搜索结果并填充我的用户列表需要 18 秒。这是我的代码：

SearchResultCollection resultList = new DirectorySearcher(CreateDirectoryEntry())
{
    Filter = ("(&(objectClass=user) (cn=*" + SearchTerm + "*))"),
    PropertiesToLoad =
    {
        "givenName",
        "sn",
        "sAMAccountName",
        "mail"
    }
}.FindAll();

foreach (SearchResult result in resultList)
{
    ADUser thisUser = new ADUser();

    try
    {
        thisUser.Firstname = result.Properties["givenName"][0].ToString();
    }
    catch
    {
        thisUser.Firstname = "Firstname not found";
    }
    try
    {
        thisUser.Lastname = result.Properties["sn"][0].ToString();
    }
    catch
    {
        thisUser.Lastname = "Lastname not found";
    }
    try
    {
        thisUser.EmailAddress = result.Properties["mail"][0].ToString();
    }
    catch
    {
        thisUser.EmailAddress = "Email address not found";
    }

    UserList.Add(thisUser);
}

它很普通，没有做任何花哨的事情。知道为什么这会这么慢，或者关于我可以做些什么来加快速度有什么建议吗？

更新

根据评论和回答，我从代码中删除了空检查。所以现在看起来像这样：

foreach (SearchResult result in resultList)
{
    ADUser thisUser = new ADUser();

    thisUser.Firstname = result.Properties["givenName"][0].ToString();
    thisUser.Lastname = result.Properties["sn"][0].ToString();
    thisUser.EmailAddress = result.Properties["mail"][0].ToString();

    UserList.Add(thisUser);
}

这并没有提高性能。我可以看到这个循环仍然需要大约 18 秒，即使只返回一个结果也是如此。（这也证明了我的广告中糟糕的数据意味着我需要这个空检查！）

Answer 1

你可以尝试类似的方法：

foreach (SearchResult result in resultList)
            {
                ADUser thisUser = new ADUser();
                if(result.Properties["givenName"][0] != null)
                    thisUser.Firstname = result.Properties["givenName"][0].ToString();
                else
                    thisUser.Firstname = "Firstname not found";

                if(thisUser.Lastname = result.Properties["sn"][0] != null)
                    thisUser.Lastname = result.Properties["sn"][0].ToString();
                else
                    thisUser.Lastname = "Lastname not found";

                if(result.Properties["mail"][0] != null)
                    thisUser.EmailAddress = result.Properties["mail"][0].ToString();
                else
                    thisUser.EmailAddress = "Email address not found";

                UserList.Add(thisUser);
            }

Answer 2

您在设置 thisUser 的属性时依赖于例外情况，这取决于您的目录，对于用户来说，可能并非如此 exceptional他们的 givenName、sn、and/or mail 属性已填充。如果您的搜索结果列表很长，所有这些例外情况都会累加起来。考虑检查是否存在所需的属性而不是使用 try/catch 块：

thisUser.Firstname = result.Properties.Contains("givenName")
    ? result.Properties["givenName"][0].ToString()
    : "Firstname not found";
thisUser.Lastname = result.Properties.Contains("sn")
    ? result.Properties["sn"][0].ToString()
    : "Lastname not found";
thisUser.EmailAddress = result.Properties.Contains("mail")
    ? result.Properties["mail"][0].ToString()
    : "Email address not found";

您可以使用 null-conditional operators from C# 6 with the null-coalescing operator 将其简化为以下内容：

thisUser.Firstname = result.Properties["givenName"]?[0]?.ToString() ?? "Firstname not found";
thisUser.Lastname = result.Properties["sn"]?[0]?.ToString() ?? "Lastname not found";
thisUser.EmailAddress = result.Properties["mail"]?[0]?.ToString() ?? "Email address not found";

为什么我的目录搜索需要这么长时间？

Why is my directory search taking so long?

.net

c#

directoryservices

asp.net-web-api

directorysearcher