LNT.MailService 1.2.0

LNT.MailService

A simple and efficient email sending library for ASP.NET Core applications, built on top of MailKit and MimeKit. This library provides a clean abstraction for sending emails with minimal configuration and easy dependency injection integration.

New in Version 1.2.0

• Support connect on port 465 (SSL)

Features

• 🚀 Easy integration with ASP.NET Core dependency injection
• 📧 Support for HTML email content
• 🔐 Secure SMTP authentication with TLS
• 📝 Built-in logging support
• ⚡ Async/await pattern for better performance
• 🎯 Simple and intuitive API
• 🛡️ Exception handling with detailed logging

Installation

Install the package via NuGet Package Manager:

dotnet add package LNT.MailService

Or via Package Manager Console:

Install-Package LNT.MailService

Or add it directly to your .csproj file:

<PackageReference Include="LNT.MailService" Version="1.2.0" />

Requirements

• .NET 8.0 or later
• ASP.NET Core application

Quick Start

1. Configure Mail Settings

Add the mail configuration to your appsettings.json:

{
  "MailSettings": {
    "Mail": "your-email@example.com",
    "DisplayName": "Your Application Name",
    "Password": "your-app-password",
    "Host": "smtp.gmail.com", # For Gmail, use smtp.gmail.com
    "Port": 587,
    "UseSSL": false # false for TLS, true for SSL on port 465
  }
}

Note: You'll need to use an App Password for Gmail.

2. Register the Service

In your Program.cs, register the mail service:

using MailSender;

var builder = WebApplication.CreateBuilder(args);

// Add mail service
builder.Services.AddMailService(builder.Configuration);

var app = builder.Build();
app.Run();

3. Use the Service

Inject IMailSender into your controllers, services, or any other class:

using MailSender;
using MailSender.Models;

public class NotificationService
{
    private readonly IMailSender _mailSender;

    public NotificationService(IMailSender mailSender)
    {
        _mailSender = mailSender;
    }

    public async Task SendWelcomeEmail(string recipientEmail)
    {
        var mailContent = new MailContent
        {
            To = recipientEmail,
            Subject = "Welcome to Our Service!",
            Body = "<h1>Welcome!</h1><p>Thank you for joining us.</p>"
        };

        bool result = await _mailSender.SendMailAsync(mailContent);
        
        if (result)
        {
            Console.WriteLine("Email sent successfully!");
        }
        else
        {
            Console.WriteLine("Failed to send email.");
        }
    }
}

Configuration Options

MailSettings (json configuration section)

MailContent

Advanced Usage

Sending HTML Emails

The library fully supports HTML content in email bodies:

var mailContent = new MailContent
{
    To = "recipient@example.com",
    Subject = "Monthly Newsletter",
    Body = @"
        <!DOCTYPE html>
        <html>
        <head>
            <style>
                body { font-family: Arial, sans-serif; }
                .header { background-color: #4CAF50; color: white; padding: 10px; }
            </style>
        </head>
        <body>
            <div class='header'>
                <h1>Newsletter</h1>
            </div>
            <p>Here's your monthly update...</p>
        </body>
        </html>
    "
};

await _mailSender.SendMailAsync(mailContent);

Using in Controllers

using Microsoft.AspNetCore.Mvc;
using MailSender;

[ApiController]
[Route("api/[controller]")]
public class EmailController : ControllerBase
{
    private readonly IMailSender _mailSender;
    private readonly ILogger<EmailController> _logger;

    public EmailController(IMailSender mailSender, ILogger<EmailController> logger)
    {
        _mailSender = mailSender;
        _logger = logger;
    }

    [HttpPost("send")]
    public async Task<IActionResult> SendEmail([FromBody] MailContent mailContent)
    {
        var result = await _mailSender.SendMailAsync(mailContent);
        
        if (result)
        {
            return Ok(new { message = "Email sent successfully" });
        }
        
        return BadRequest(new { message = "Failed to send email" });
    }
}

Security Best Practices

1. Never commit credentials: Store sensitive information in user secrets during development:

   dotnet user-secrets set "MailSettings:Password" "your-password"
   

2. Use environment variables: In production, use environment variables or secure vaults:

   export MailSettings__Password="your-password"
   

3. Use App Passwords: For services like Gmail, use app-specific passwords instead of your main account password.

4. Encrypted Configuration: Consider using Azure Key Vault or similar services for production environments.

Logging

The library includes built-in logging support. Successful email sends and errors are automatically logged using the provided ILogger<MailSender>.

To see the logs, ensure logging is configured in your appsettings.json:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "MailSender": "Information"
    }
  }
}

Troubleshooting

Common Issues

Authentication Failed

• Verify your email and password are correct
• For Gmail, ensure you're using an App Password
• Check if "Less secure app access" is enabled (if applicable)

Connection Timeout

• Verify the SMTP host and port are correct
• Check if your firewall is blocking the connection
• Ensure your hosting provider allows outbound SMTP connections

Email Not Received

• Check the recipient's spam/junk folder
• Verify the recipient email address is correct
• Check your email provider's sending limits

Dependencies

This library uses the following packages:

• MailKit (v4.15.1)
• MimeKit (v4.15.1)
• Microsoft.Extensions.* (v8.0.0)

License

This project is licensed under the MIT License.

Support

For issues, questions, or contributions, please visit the project repository or contact the author.

Author

LƯƠNG NHẬT TRƯỜNG

Changelog

Version 1.2.0

• Initial release
• Basic email sending functionality
• Dependency injection support
• HTML email support
• Built-in logging