p42Email

Email utilities for .NET apps built on MailKit: send messages via SMTP, check IMAP for new mail, list recent emails, and optionally run a background polling service that raises events when new messages arrive.

• PackageId: p42Email
• Target framework: .NET 10.0
• Language: C# 14.0
• License: MIT
• Repository: https://github.com/prod42net/p42Email

Overview

p42Email provides a small, focused abstraction around common email workflows using MailKit:

• Send emails via SMTP
• Check an IMAP mailbox for unseen messages
• Retrieve a list of recent messages
• Optionally run a hosted background service that periodically polls for email and raises a NewMailDetected event

All configuration is provided through a single Email options section (Smtp, Imap, and PollingIntervalSeconds).

Features

• SMTP send: IEmailService.SendEmailAsync(...)
• IMAP check for unseen: IEmailService.CheckNewEmailsAsync(...)
• List recent: IEmailService.GetRecentEmailsAsync(...)
• Background polling (hosted service): EmailPollingService
• New mail eventing: IEmailEvents.NewMailDetected

Requirements

• .NET SDK 10.0+
• C# 14.0
• NuGet dependency: MailKit

Installation

Check for the latest version of the package on NuGet:

dotnet add package p42Email --version 1.0.0

Or reference the project directly if you are working from source.

Configuration

Add an Email section to your appsettings.json (or other configuration source). The structure maps to EmailOptions.

{
  "Email": {
    "PollingIntervalSeconds": 60,
    "Smtp": {
      "Host": "smtp.example.com",
      "Port": 587,
      "UseSsl": true,
      "Username": "smtp-user",
      "Password": "smtp-password",
      "FromAddress": "no-reply@example.com",
      "FromDisplayName": "Example App"
      
    },
    "Imap": {
      "Host": "imap.example.com",
      "Port": 993,
      "UseSsl": true,
      "Username": "imap-user",
      "Password": "imap-password",
      "Folder": "INBOX"
    }
  }
}


Tip: Store secrets (usernames/passwords) in user secrets or environment variables in production.

## Dependency Injection Setup

Register the services in your `Program.cs` or `Startup` using the Microsoft.Extensions.* stack:

```csharp
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
using p42Email.Interfaces;
using p42Email.Options;
using p42Email.Services;

var builder = Host.CreateApplicationBuilder(args);

// Bind Email options from configuration
builder.Services.Configure<EmailOptions>(builder.Configuration.GetSection(EmailOptions.SectionName));

// Core email services
builder.Services.AddSingleton<IEmailEvents, EmailEvents>();
builder.Services.AddSingleton<IEmailService, EmailService>();

// Optional: enable background polling for new messages
builder.Services.AddHostedService<EmailPollingService>();

var app = builder.Build();
await app.RunAsync();

If you don't need background polling/events, omit the AddHostedService<EmailPollingService>() line.

Usage

Send an email

using p42Email.Interfaces;

public class MyController
{
    private readonly IEmailService _email;
    public MyController(IEmailService email) => _email = email;

    public async Task SendWelcomeAsync(string userEmail)
    {
        await _email.SendEmailAsync(
            toEmail: userEmail,
            subject: "Welcome!",
            body: "<p>Thanks for joining.</p>",
            isHtml: true
        );
    }
}

Check for new (unseen) messages

int unseen = await _email.CheckNewEmailsAsync();
Console.WriteLine($"Unseen messages: {unseen}");

Get recent messages

using p42Email.Models;

IReadOnlyList<EmailMessageInfo> recent = await _email.GetRecentEmailsAsync(take: 20);
foreach (var m in recent)
{
    Console.WriteLine($"[{m.Date}] {m.From} -> {m.Subject}");
}

React to new mail via event

When using the hosted polling service, subscribe to IEmailEvents.NewMailDetected to react to new unseen messages detected during polling.

using p42Email.Interfaces;

public sealed class NewMailHandler
{
    public NewMailHandler(IEmailEvents events)
    {
        events.NewMailDetected += OnNewMailDetected;
    }

    private void OnNewMailDetected(int unseenCount)
    {
        Console.WriteLine($"New unseen messages detected: {unseenCount}");
        // Add your handling logic here (e.g., trigger processing workflow)
    }
}

Public API Surface (at a glance)

Interfaces and models you will commonly use:

• p42Email.Interfaces.IEmailService

  • Task SendEmailAsync(string toEmail, string subject, string body, bool isHtml = true, CancellationToken ct = default)
  • Task<int> CheckNewEmailsAsync(CancellationToken ct = default)
  • Task<IReadOnlyList<EmailMessageInfo>> GetRecentEmailsAsync(int take = 50, CancellationToken ct = default)

• p42Email.Interfaces.IEmailEvents

  • event Action<int>? NewMailDetected

• p42Email.Options.EmailOptions

  • SmtpOptions Smtp, ImapOptions Imap, int PollingIntervalSeconds = 60

Notes

• SMTP defaults typically: 587 with STARTTLS or SSL depending on provider; IMAP defaults typically: 993 SSL. Adjust to your provider's requirements.
• Ensure less-secure app access or app passwords are configured as required by your email provider.
• For production, do not commit secrets. Prefer environment variables or a secret manager.

License

MIT © pro42net

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The NuGet package includes a small icon (prod42net.jpg) and this README for package metadata.