Umbraco-CMS/src/Umbraco.Web/HealthCheck/NotificationMethods/EmailNotificationMethod.cs

using System;
using System.Net.Mail;
using System.Threading;
using System.Threading.Tasks;
using Umbraco.Core;
using Umbraco.Core.Configuration;
using Umbraco.Core.Services;

namespace Umbraco.Web.HealthCheck.NotificationMethods
{
    [HealthCheckNotificationMethod("email")]
    public class EmailNotificationMethod : NotificationMethodBase
    {
        private readonly ILocalizedTextService _textService;

        internal EmailNotificationMethod(ILocalizedTextService textService)
        {
            var recipientEmail = Settings["recipientEmail"]?.Value;
            if (string.IsNullOrWhiteSpace(recipientEmail))
            {
                Enabled = false;
                return;
            }

            RecipientEmail = recipientEmail;

            _textService = textService ?? throw new ArgumentNullException(nameof(textService));
        }

        public string RecipientEmail { get; }

        public override async Task SendAsync(HealthCheckResults results, CancellationToken token)
        {
            if (ShouldSend(results) == false)
            {
                return;
            }

            if (string.IsNullOrEmpty(RecipientEmail))
            {
                return;
            }

            var message = _textService.Localize("healthcheck/scheduledHealthCheckEmailBody", new[]
            {
                DateTime.Now.ToShortDateString(),
                DateTime.Now.ToShortTimeString(),
                results.ResultsAsHtml(Verbosity)
            });

            var subject = _textService.Localize("healthcheck/scheduledHealthCheckEmailSubject");

            using (var client = new SmtpClient())
            using (var mailMessage = CreateMailMessage(subject, message))
            {
                if (client.DeliveryMethod == SmtpDeliveryMethod.Network)
                {
                    await client.SendMailAsync(mailMessage);
                }
                else
                {
                    client.Send(mailMessage);
                }
            }
        }

        private MailMessage CreateMailMessage(string subject, string message)
        {
            var to = UmbracoConfig.For.UmbracoSettings().Content.NotificationEmailAddress;

            if (string.IsNullOrWhiteSpace(subject))
                subject = "Umbraco Health Check Status";

            return new MailMessage(to, RecipientEmail, subject, message)
            {
                IsBodyHtml = message.IsNullOrWhiteSpace() == false && message.Contains("<") && message.Contains("</")
            };
        }
    }
}