c# - 如何在使用托管 ODP.NET 时从 C# 查询 LDAP 以解析 Oracle TNS 主机名？

Question

除了我之前的 Question ，我设法用 help from the Oracle forums 回答了自己，我现在还有另一个问题，它是之前的问题(提供背景)。

我希望直接从我的 C# 代码查询 LDAP，以执行 Oracle TNS 主机名的 LDAP 查找，以便获取连接字符串。这通常存储在 tnsnames.ora 中，我的组织使用 LDAP(通过 ldap.ora)从使用 Active Directory 的 LDAP 服务器解析主机名。

但是，我在我的 C# 应用程序中使用 ODP.NET, Managed Driver Beta (Oracle.ManagedDataAccess.dll)，它不支持 LDAP，正如我之前提到的 release notes 指向的 Oracle forum reply 中提到的那样。这就是为什么我希望直接从 C# 查询 LDAP。

我找到了一种使用 DirectoryEntry 和 DirectorySearcher 来执行此 here 的方法，但我不知道将什么作为参数放入 DirectorySearcher .我可以访问以下格式的 ldap.ora:

# LDAP.ORA Configuration
# Generated by Oracle configuration tools.
DEFAULT_ADMIN_CONTEXT = "dc=xx,dc=mycompany,dc=com"
DIRECTORY_SERVERS = (ldap_server1.mycompany.com:389:636,ldap_server2.mycompany.com:389:636, ...) DIRECTORY_SERVER_TYPE = OID

但是，我如何将其映射到在我的 C# 代码中设置 LDAP 查询？

Answer 1

除了我在 accepted Answer 中的第二条评论之外，这是执行 LDAP 查找的代码，它改进了我找到的原始版本 here 。它还处理 ldap.ora 文件中的服务器列表，其中包括多个分隔的端口号。

private static string ResolveServiceNameLdap(string serviceName)
{
    string tnsAdminPath = Path.Combine(@"C:\Apps\oracle\network\admin", "ldap.ora");
    string connectionString = string.Empty;

    // ldap.ora can contain many LDAP servers
    IEnumerable<string> directoryServers = null;

    if (File.Exists(tnsAdminPath))
    {
        string defaultAdminContext = string.Empty;

        using (var sr = File.OpenText(tnsAdminPath))
        {
            string line;

            while ((line = sr.ReadLine()) != null)
            {
                // Ignore commetns
                if (line.StartsWith("#"))
                {
                    continue;
                }

                // Ignore empty lines
                if (line == string.Empty)
                {
                    continue;
                }

                // If line starts with DEFAULT_ADMIN_CONTEXT then get its value
                if (line.StartsWith("DEFAULT_ADMIN_CONTEXT"))
                {
                    defaultAdminContext = line.Substring(line.IndexOf('=') + 1).Trim(new[] {'\"', ' '});
                }

                // If line starts with DIRECTORY_SERVERS then get its value
                if (line.StartsWith("DIRECTORY_SERVERS"))
                {
                    string[] serversPorts = line.Substring(line.IndexOf('=') + 1).Trim(new[] {'(', ')', ' '}).Split(',');
                    directoryServers = serversPorts.SelectMany(x =>
                    {
                        // If the server includes multiple port numbers, this needs to be handled
                        string[] serverPorts = x.Split(':');
                        if (serverPorts.Count() > 1)
                        {
                            return serverPorts.Skip(1).Select(y => string.Format("{0}:{1}", serverPorts.First(), y));
                        }

                        return new[] {x};
                    });
                }
            }
        }

        // Iterate through each LDAP server, and try to connect
        foreach (string directoryServer in directoryServers)
        {
            // Try to connect to LDAP server with using default admin contact
            try
            {
                var directoryEntry = new DirectoryEntry("LDAP://" + directoryServer + "/" + defaultAdminContext, null, null, AuthenticationTypes.Anonymous);
                var directorySearcher = new DirectorySearcher(directoryEntry, "(&(objectclass=orclNetService)(cn=" + serviceName + "))", new[] { "orclnetdescstring" }, SearchScope.Subtree);

                SearchResult searchResult = directorySearcher.FindOne();

                var value = searchResult.Properties["orclnetdescstring"][0] as byte[];

                if (value != null)
                {
                    connectionString = Encoding.Default.GetString(value);
                }

                // If the connection was successful, then not necessary to try other LDAP servers
                break;
            }
            catch
            {
                // If the connection to LDAP server not successful, try to connect to the next LDAP server
                continue;
            }
        }

        // If casting was not successful, or not found any TNS value, then result is an error message
        if (string.IsNullOrEmpty(connectionString))
        {
            connectionString = "TNS value not found in LDAP";
        }
    }
    else
    {
        // If ldap.ora doesn't exist, then return error message
        connectionString = "ldap.ora not found";
    }

    return connectionString;
}