Azure Communication Service - .NET Client with ConnectionString

The Azure Communication Service is a fairly new but already popular service for sending emails at scale. In this article, I would like to show you how you can use the service via a connection string in your .NET project.

Be aware that the connection string should be used primarily with software that is not operated on Azure in a managed identity context. If you are on Azure, use the more secure variant via the Managed Identity! See Azure Communication Service - .NET Client with Managed Identity

The email client

To be able to use the Azure Communication Service in your .NET project, you need the official NuGet package Azure.Communication.Email . With the help of this package and the corresponding using, the client can be initialised directly.

1using Azure.Communication.Email
2
3// create instance
4EmailClient mailClient = new(myConnectionString);
5
6// send mail
7EmailSendOperation emailSendOperation = await mailClient.SendAsync(
8    Azure.WaitUntil.Completed, fromAddress, toMailAddress, subject, htmlBody, plainTextContent: null, cancellationToken)
9    .ConfigureAwait(false);

The simple client class

A very simple class - without error handling, without logging, without retry can look like this:

 1public sealed class AzureCommunicationServiceEMailClient
 2{
 3    private readonly EmailClient _mailClient;
 4    private readonly EMailOptions _emailOptions;
 5    private readonly CommunicationServiceOptions _acsOptions;
 6
 7    public AzureCommunicationServiceEMailClient(
 8        IOptions<EMailOptions> emailOptions,
 9        IOptions<CommunicationServiceOptions> acsOptions)
10    {
11        _emailOptions = emailOptions.Value;
12        _acsOptions = acsOptions.Value;
13
14        _mailClient = new(_acsOptions.ConnectionString);
15    }
16
17    public async Task Send(string toMailAddress, string subject, string htmlBody, CancellationToken ct)
18    {
19        string fromAddress = _emailOptions.FromAddress;
20
21        await _mailClient.SendAsync(
22                Azure.WaitUntil.Completed, fromAddress, toMailAddress, subject, htmlBody, plainTextContent: null, ct);
23    }
24}

The following two classes are used for the options:

 1public class EMailOptions
 2{
 3    [Required]
 4    [EmailAddress]
 5    public string FromAddress { get; set; } = null!; // [email protected]
 6}
 7
 8public class CommunicationServiceOptions
 9{
10    [Required]
11    public string ConnectionString { get; set; } = null!; // endpoint=https://<your-communication-service>.<location>.communication.azure.com/;accesskey=abcxyz
12}

As the EmailClient itself is thread-safe, the entire AzureCommunicationServiceEMailClient class can be used in a singleton scenario.

Azure Communication Service - .NET Client with ConnectionString