SmtpEmail Library

This library provides a simple way to send fault tolerant SMTP emails in .NET applications using OneOf

Features

• Supports sending plain text and HTML emails.
• Supports sending emails to multiple recipients and adding CC and BCC recipients.
• Uses OneOf return types.

Installation

To install the library, run the following command in the Package Manager Console:

dotnet add package Biplov.Email.Smtp --version 0.1.3

Usage

To use the library first configure the SmtpCredentials in appsettings.json then via services then invoke the AddSmtpEmailService method passing the IAsncPolicy of Polly.

  "SmtpCredentials": {
    "Host": "<Your Smtp host>",
    "Port": <Your smtp port>,
    "Username": "<Your smtp username>",
    "Password": "<Your smtp password>",
    "UseSsl": <true or false>,
    "Timeout": <timeout in milliseconds>
}

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<SmtpCredentials>(Configuration.GetSection("SmtpCredentials"));
    
    var asyncPolicy = Policy
        .TimeoutAsync(TimeSpan.FromSeconds(30))
        .WrapAsync(Policy
            .Handle<TimeoutException>()
            .WaitAndRetryAsync(
                retryCount: 3,
                sleepDurationProvider: attempt => TimeSpan.FromSeconds(Math.Pow(2, attempt))
            ));

    services.AddSmtpEmailService(asyncPolicy);
}

Example usage

var emailService = serviceProvider.GetRequiredService<IEmailService>();

var result = await emailService.SendAsync(
    "Hello World",
    "This is a test email from SmtpEmail",
    new List<string> { "recipient@example.com" },
    "sender@example.com"
);

result.Match(
    success => Console.WriteLine("Email sent successfully."),
    formatException => Console.WriteLine($"Email format exception: {formatException.Message}"),
    authenticationException => Console.WriteLine($"Authentication failed: {authenticationException.Message}"),
    smtpException => Console.WriteLine($"SMTP error: {smtpException.Message}"),
    timeoutException => Console.WriteLine($"SMTP connection timed out: {timeoutException.Message}"),
    exception => Console.WriteLine($"Unhandled exception: {exception.Message}")
);