MushCOA.EmailLibrary 1.0.1

MushCOA.EmailLibrary

Reusable .NET email library using MailKit.

Features

• Send HTML emails
• Send plain text emails
• Send attachments from file path
• Send attachments from byte array
• Supports To, CC, BCC, and Reply-To
• Supports dependency injection
• SMTP settings from appsettings.json, User Secrets, environment variables, or other .NET configuration sources

Installation

dotnet add package MushCOA.EmailLibrary

Or install from Visual Studio:

Manage NuGet Packages → Browse → Search MushCOA.EmailLibrary → Install

Configuration

Add this to appsettings.json or appsettings.Development.json:

{
  "Email": {
    "SmtpHost": "smtp.example.com",
    "SmtpPort": 587,
    "Username": "your-smtp-username",
    "Password": "your-smtp-password",
    "DefaultFromEmail": "noreply@example.com",
    "DefaultFromName": "Example App",
    "SecureSocketOption": "StartTls",
    "TimeoutMilliseconds": 30000
  }
}

Do not store real SMTP passwords in source control. Use User Secrets, environment variables, Azure Key Vault, or another secure configuration provider.

Register the service

In Program.cs:

using EmailLibrary;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEmailLibrary(builder.Configuration);

var app = builder.Build();

Send an email

Inject IEmailService into your controller or service:

using EmailLibrary;
using Microsoft.AspNetCore.Mvc;

public class EmailTestController : Controller
{
    private readonly IEmailService _emailService;

    public EmailTestController(IEmailService emailService)
    {
        _emailService = emailService;
    }

    public async Task<IActionResult> SendTestEmail()
    {
        await _emailService.SendAsync(new EmailRequest
        {
            To =
            {
                new EmailAddress("user@example.com", "Test User")
            },

            Subject = "Test Email",

            TextBody = "Hello, this is a plain text email.",

            HtmlBody = "<p>Hello, this is an <strong>HTML email</strong>.</p>"
        });

        return Content("Email sent successfully.");
    }
}

Send email with attachment from file

await _emailService.SendAsync(new EmailRequest
{
    To =
    {
        new EmailAddress("user@example.com", "Test User")
    },

    Subject = "Document Attached",

    HtmlBody = "<p>Please see the attached document.</p>",

    Attachments =
    {
        EmailAttachment.FromFile(
            @"C:\Temp\Document.pdf",
            "Document.pdf",
            "application/pdf")
    }
});

Send email with attachment from byte array

var fileBytes = File.ReadAllBytes(@"C:\Temp\Document.pdf");

await _emailService.SendAsync(new EmailRequest
{
    To =
    {
        new EmailAddress("user@example.com", "Test User")
    },

    Subject = "Generated Document",

    HtmlBody = "<p>Your generated document is attached.</p>",

    Attachments =
    {
        EmailAttachment.FromBytes(
            fileBytes,
            "Document.pdf",
            "application/pdf")
    }
});

Configuration section name

By default, the library reads from the Email section:

builder.Services.AddEmailLibrary(builder.Configuration);

If your config section has a different name, use:

builder.Services.AddEmailLibrary(builder.Configuration, "SmtpSettings");