Can mailkit in ASP.NET read a config file?

Question

I'm trying to build a web-app in ASP.NET core 3.1 for managing a company's clients. When the user saves a new client in the database, I want the app to send a welcome mail to the client.

I tried doing that with the SmtpClient class but microsoft itself seems to discourage that:

Important. We don't recommend that you use the SmtpClient class for new development because SmtpClient doesn't support many modern protocols. Use MailKit or other libraries instead.

So I decided to use the MailKit library and I've coded this so far:

// Send a welcome email.
MimeMessage message = new MimeMessage();
message.From.Add(new MailboxAddress("CompanyName", "email"));
message.To.Add(MailboxAddress.Parse(obj.Email));
message.Subject = "Welcome mail";
message.Body = new TextPart("plain")
    {
        Text = @"Welcome " + obj.Name + "!"
    };
SmtpClient client = new SmtpClient();
client.Connect("smtp.gmail.com", 465, true);
client.Authenticate("mail", "password");
client.Send(message);
client.Disconnect(true);
client.Dispose();

Note that the above segment of code is written in the controller that handles the storing the new client. Right after the validation and saving the db changes, I send the email.

This works fine, but I want to see if it's possible to read all things like the mail address, its password, the smtp client, the port etc, from a config file in the app folder, instead of them being hard-coded. I think that MailKit can't read the web.config file, is there anything else I can do? Any help would be appreciated!

There's nothing stopping you from writing code that can and provide it to MailKit. — phuzi, Jan 04 '22 at 12:34
https://stackoverflow.com/questions/4595288/reading-a-key-from-the-web-config-using-configurationmanager — VDWWD, Jan 04 '22 at 14:36
Although @TheFloods answer is correct, you should consider `IOptionsSnapshot` (transient) or `IOptionsMonitor` (singleton) if you want to change your mail settings at runtime. [Docs](https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-3.1) — HMZ, Jan 04 '22 at 18:53

TheFloods · Accepted Answer · 2022-01-07T06:51:50.880

Yes you can!

In you Startup.cs :

services.Configure<EmailSettings>(Configuration.GetSection("EmailSection"));

Create the configuration class EmailSettings :

public class EmailSettings
{
    public string Smtp { get; set; }
    public string SendFrom { get; set; }
    public string Password { get; set; }
    public int Port { get; set; }
}

Then add this on you appsettings.json :

...
"EmailSection": {
   "Smtp": "smtp.gmail.com",
   "SendFrom": "noreply@domain.com",
   "Password": "123456789",
   "Port": 465
 },
 ...

Finally, you can use dependency injection for call you configuration class EmailSettings from a controller or whatever you want :

public class HomeController : Controller
{
   private EmailSettings _emailSettings;
   // Constructor of controller
   public HomeController : Controller (IOptions<EmailSettings> emailSettings)
   {
      _emailSettings = emailSettings.Value;
   }
   
   public IActionResult Index()
   {
      string getSmtp = _emailSettings.Smtp;
      string getPassword = _emailSettings.Password;
      // ...
   }
}

thank you! Your code was really simple and understandable! I want to point out that the only change I made was at the constructor: _emailSettings = emailSettings.Value; Without that I got a "Cannot implicitly convert type 'Microsoft.Extensions.Options.IOptions to ..." error. — Don, Jan 05 '22 at 21:58
No problem. You are right, I have edit the code here upper : '_emailSettings = emailSettings.Value;' — TheFloods, Jan 07 '22 at 06:53

Can mailkit in ASP.NET read a config file?

1 Answers1