Tag Archives: HttpRequestMessage

SendGrid – Azure e-mail functionality

In this post, I discussed the prospect of sending an e-mail from an Azure function in order to alert someone that something had gone wrong. In one of the comments, it was suggested that I should look into a third party tool called “SendGrid”, and this post is the result of that investigation.

Azure Configuration

SendGrid is a third party application, and so the first thing you need to do is to create an account:

The free tier covers you for 25,000 e-mails per month. However, you do get a scary warning that, because this isn’t a Microsoft product, it is not covered by Azure credits.

Anyway, click create and, after a while, you’re new SendGrid Account should be created:

You’ll need to get the API Key: to do this, select Manage:

That takes you to https://app.sendgrid.com, where you can select to create an API Key:

Clearly, you wouldn’t want a full access account to just send an e-mail in real life… but Restricted Access has a form that would take longer to fill in, and I can’t be mythered*… so we’ll go with full access for now.

Once you’ve created it, and given it a name, you should have a key (remember that key – don’t write it down, or copy it, you must remember it!).

Code

Create a new Function App, and add the SendGrid NuGet package:

https://www.nuget.org/packages/Sendgrid/

In this case, let’s create a HttpTrigger function (this will fire when a web address is accessed); the body of which needs to look something like this:

        [FunctionName("SendEmail")]
        public static async Task<HttpResponseMessage> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)]HttpRequestMessage req, 
            TraceWriter log)
        {
            log.Info("C# HTTP trigger function processed a request.");

            // parse query parameter
            var addresses = req.GetQueryNameValuePairs();
            string[] addressArr = addresses
                .Where(a => a.Key == "address")
                .Select(a => a.Value).ToArray();

            if (addressArr.Count() == 0)
            {
                return req.CreateResponse(HttpStatusCode.BadRequest, 
                    "Please pass an address in the query string");
            }
            else
            {
                HttpStatusCode status = await CallSendEmailAsync(
                    "noreply@test.com", addressArr, "test e-mail",
                    "Once more unto the breach, dear friends, once more;\n" +
                    "Or close the wall up with our English dead.   \n" +
                    "In peace there's nothing so becomes a man     \n" +
                    "As modest stillness and humility:             \n" +
                    "But when the blast of war blows in our ears,  \n" +
                    "Then imitate the action of the tiger;         \n" +
                    "Stiffen the sinews, summon up the blood,");
                switch (status)
                {
                    case HttpStatusCode.OK:
                    case HttpStatusCode.Accepted:
                    {
                        return req.CreateResponse(status, "Mail Successfully Sent");
                    }
                    default:
                    {
                        return req.CreateResponse(status, "Unable to send e-mail");
                    }
                }
            }
        }

The `CallSendEmailAsync` helper method might look like this:

public static async Task<HttpStatusCode> CallSendEmailAsync(string from, string[] recipients, string subject, string body)
{
    EmailAddress fromAddress = new EmailAddress(from);
 
    SendGridMessage message = new SendGridMessage()
    {
        From = fromAddress,
        Subject = subject,
        HtmlContent = body
    };
 
    message.AddTos(recipients.Select(r => { return new EmailAddress(r); }).ToList());
   
    string sendGridApiKey = "AB.keythisisthekey.nkfdhfkjfhkjfd0ei8L9xTyaTCzy_sV5gPJNX-3";
 
    SendGridClient client = new SendGridClient(sendGridApiKey);
    Response response = await client.SendEmailAsync(message);
 
    return response.StatusCode;
}

The key is the string that I said you should remember earlier.

You can just paste the URL into a browser, give it the e-mail addresses in the format:

https://url.com?address=my@email.com&my-second@email.com

As you will see from the link at the bottom of this post, OK (200) signifies that the message is valid, but not queued to be delivered; and Accepted (202) indicates that the message is valid and queued. My guess is that if you get an OK, it means that the mail has already been delivered.

Footnotes

* It probably took longer to type this out than to do it.

References

https://go.sendgrid.com/

https://sendgrid.com/docs/API_Reference/Web_API_v3/Mail/errors.html