Azure Function implementation to send a message to Teams

azure-function-posting-to-teams.cs

private static readonly HttpClient HttpClient = new HttpClient();

[FunctionName("InvokeTeamsHook")]
public static async Task Run(
    [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "InvokeTeams")]
    HttpRequestMessage req,
    ILogger log)
{
    var message = await req.Content.ReadAsAsync<IncomingTeamsMessage>();

    var address = Environment.GetEnvironmentVariable("WebhookUrl", EnvironmentVariableTarget.Process);
    var plainTeamsMessage = new PlainTeamsMessage { Title = message.Title, Text = message.Text };
    var content = new StringContent(JsonConvert.SerializeObject(plainTeamsMessage), Encoding.UTF8, "application/json");
    
    await HttpClient.PostAsync(address, content);
}

public class IncomingTeamsMessage
{
    public string Title { get; set; }
    public string Text { get; set; }
}

private class PlainTeamsMessage
{
    public string Title { get; set; }
    public string Text { get; set; }
}