public class UserEmailSenderConfiguration : TruckingServiceBase, IUserEmailSenderConfiguration, ITransientDependency

{

    /// <summary>

    /// Gets a setting value by checking. Throws <see cref="AbpException"/> if it's null or empty.

    /// </summary>

    /// <param name="name">Name of the setting</param>

    /// <returns>Value of the setting</returns>

    protected string GetNotEmptySettingValue(string name)

    {

        var value = SettingManager.GetSettingValue(name);

        if (value.IsNullOrEmpty())

        {

            throw new AbpException(String.Format("Setting value for '{0}' is null or empty!", name));

        }

        return value;

    }

    /// <summary>

    /// SMTP Host name/IP.

    /// </summary>

    public string Host

    {

        get { return GetNotEmptySettingValue(AppSettings.Smtp.Host); }

    }

    /// <summary>

    /// SMTP Port.

    /// </summary>

    public int Port

    {

        get { return SettingManager.GetSettingValue<int>(AppSettings.Smtp.Port); }

    }

    /// <summary>

    /// User name to login to SMTP server.

    /// </summary>

    public string UserName

    {

        get { return GetNotEmptySettingValue(AppSettings.Smtp.UserName); }

    }

    /// <summary>

    /// Password to login to SMTP server.

    /// </summary>

    public string Password

    {

        get { return GetNotEmptySettingValue(AppSettings.Smtp.Password); }

    }

    /// <summary>

    /// Domain name to login to SMTP server.

    /// </summary>

    public string Domain

    {

        get { return SettingManager.GetSettingValue(AppSettings.Smtp.Domain); }

    }

    /// <summary>

    /// Is SSL enabled?

    /// </summary>

    public bool EnableSsl

    {

        get { return SettingManager.GetSettingValue<bool>(AppSettings.Smtp.EnableSsl); }

    }

    /// <summary>

    /// Use default credentials?

    /// </summary>

    public bool UseDefaultCredentials

    {

        get { return SettingManager.GetSettingValue<bool>(AppSettings.Smtp.UseDefaultCredentials); }

    }

    public string DefaultAddress

    {

        get { return GetNotEmptySettingValue(AppSettings.Smtp.DefaultAddress); }

    }

    public string DefaultDisplayName

    {

        get { return SettingManager.GetSettingValue(AppSettings.Smtp.DefaultDisplayName); }

    }

}

public class UserSmtpEmailSender : IUserSmtpEmailSender, ITransientDependency

{

    private readonly IUserEmailSenderConfiguration _configuration;

    public UserSmtpEmailSender(IUserEmailSenderConfiguration configuration)

    {

        _configuration = configuration;

    }

    public async Task SendAsync(string to, string subject, string body, bool isBodyHtml = true)

    {

        await SendAsync(_configuration.DefaultAddress, to, subject, body, isBodyHtml);

    }

    public void Send(string to, string subject, string body, bool isBodyHtml = true)

    {

        Send(_configuration.DefaultAddress, to, subject, body, isBodyHtml);

    }

    public async Task SendAsync(string from, string to, string subject, string body, bool isBodyHtml = true)

    {

        await SendAsync(new MailMessage(from, to, subject, body) {IsBodyHtml = isBodyHtml});

    }

    public void Send(string from, string to, string subject, string body, bool isBodyHtml = true)

    {

        Send(new MailMessage(from, to, subject, body) {IsBodyHtml = isBodyHtml});

    }

    public async Task SendAsync(MailMessage mail, bool normalize = true)

    {

        if (normalize)

            NormalizeMail(mail);

        await SendEmailAsync(mail);

    }

    public void Send(MailMessage mail, bool normalize = true)

    {

        if (normalize)

            NormalizeMail(mail);

        SendEmail(mail);

    }

    public SmtpClient BuildClient()

    {

        var host = _configuration.Host;

        var port = _configuration.Port;

        var smtpClient = new SmtpClient(host, port);

        try

        {

            if (_configuration.EnableSsl)

                smtpClient.EnableSsl = true;

            if (_configuration.UseDefaultCredentials)

            {

                smtpClient.UseDefaultCredentials = true;

            }

            else

            {

                smtpClient.UseDefaultCredentials = false;

                var userName = _configuration.UserName;

                if (!userName.IsNullOrEmpty())

                {

                    var password = _configuration.Password;

                    var domain = _configuration.Domain;

                    smtpClient.Credentials = !domain.IsNullOrEmpty()

                        ? new NetworkCredential(userName, password, domain)

                        : new NetworkCredential(userName, password);

            }

        }

        return smtpClient;

    }

    catch

    {

            smtpClient.Dispose();

            throw;

        }

    }

    /// <summary>

    ///     Normalizes given email.

    ///     Fills <see cref="MailMessage.From" /> if it's not filled before.

    ///     Sets encodings to UTF8 if they are not set before.

    /// </summary>

    /// <param name="mail">Mail to be normalized</param>

    protected virtual void NormalizeMail(MailMessage mail)

    {

        if ((mail.From == null) || mail.From.Address.IsNullOrEmpty())

            mail.From = new MailAddress(

                _configuration.DefaultAddress,

                _configuration.DefaultDisplayName,

                Encoding.UTF8

            );

        if (mail.HeadersEncoding == null)

            mail.HeadersEncoding = Encoding.UTF8;

        if (mail.SubjectEncoding == null)

            mail.SubjectEncoding = Encoding.UTF8;

        if (mail.BodyEncoding == null)

            mail.BodyEncoding = Encoding.UTF8;

    }

    protected async Task SendEmailAsync(MailMessage mail)

    {

        using (var smtpClient = BuildClient())

        {

            await smtpClient.SendMailAsync(mail);

        }

    }

    protected void SendEmail(MailMessage mail)

    {

        using (var smtpClient = BuildClient())

        {

            smtpClient.Send(mail);

        }

    }

}