Send Emails through Smart Integration Direct Connections

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Globalization;
using System.IO;
using System.Linq;
using Microsoft.CSharp;
using OneStream.Finance.Database;
using OneStream.Finance.Engine;
using OneStream.Shared.Common;
using OneStream.Shared.Database;
using OneStream.Shared.Engine;
using OneStream.Shared.Wcf;
using OneStream.Stage.Database;
using OneStream.Stage.Engine;
using System.Net.Mail;
using System.Net;
using System.Net.Security;
using System.Text.RegularExpressions;
using System.Security.Cryptography.X509Certificates;
namespace OneStream.BusinessRule.Extender.smtp_direct_test
{
    public class MainClass
    {        
        public SessionInfo SI;
        private const string smtpHostName = "smtp.azurecomm.net"; // expected name to match the cert.
        
        
        public object Main(SessionInfo si, BRGlobals globals, object api, ExtenderArgs args)
        {
 var client = new SmtpClient();
 var email = new MailMessage();            
            try
            {
                SI = si;
                // Add custom validation callback to look for expected cert (Host will be localhost, which causes this to fail without a custom callback)
                ServicePointManager.ServerCertificateValidationCallback += ValidationCallback;
                
     client.UseDefaultCredentials = false;
     client.Port = 20542;
     client.Host = "localhost";
                client.EnableSsl = true;
                client.Credentials = new System.Net.NetworkCredential("<UserName>", "<Password>");            
    
     email.From = new MailAddress("DoNotReply@domain.com");
     email.To.Add("test@onestreamsoftware.com");
     email.Subject = "Test from SIC Gateway";
     email.IsBodyHtml = false;
     email.Body = "Forwarded test from SIC Gateway";
    
     client.Send(email);
                                                                
                return null;                
            }
            catch (Exception ex)
            {
                throw ErrorHandler.LogWrite(si, new XFException(si, ex));
            }
            finally
            {
                // Remove the custom ValidationCallback. It's recommended to remove this before any other network calls.
                ServicePointManager.ServerCertificateValidationCallback -= ValidationCallback;
                email.Dispose();
                client.Dispose();
            }
        }
        
        public bool ValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        {
            var policyErrors = (sslPolicyErrors as SslPolicyErrors?) ?? SslPolicyErrors.None;
            var certSubject = certificate?.Subject ?? string.Empty;
            var certName = string.Empty;
            
            // Extract the certName from the certSubject
            string namePattern = @"CN=([^,]+)";
            var match = Regex.Match(certSubject, namePattern);
            if (match.Success)
            {
                certName = match.Groups[1].Value;
                
            }
            if (                        
                (policyErrors == SslPolicyErrors.RemoteCertificateNameMismatch || policyErrors == SslPolicyErrors.None)
                && certName == smtpHostName)
            {
                // verify the certName matches the expected smtpHostName. No other SslPolicyErrors should be present.
                return true;
            }
            else
            {
                return false;
            }                
        }
    }
}