Using Google Tag Manager and UTM

jacobrosenfeld

Does anyone know how to use Google Tag Manager to subscribe users to a list? I can pull the email address from the Data Layer, that's easy, I can't figure out how to post it to the Sendy API.

Thanks.

espen

Sending a HTTP request using JavaScript to the form URL should work I would think.

jacobrosenfeld

How would I do that?

workhorse

How did the email address get into the datalayer in the first place? I ask b/c it would probably be more reliable to submit it from the web server to Sendy API rather than fire a GTM tag to the Sendy API. GTM is blocked by ad blockers for example. Not only that, but doing this in GTM would expose your Sendy API key which is a security issue.

jacobrosenfeld

That's a good point but the form is a third party form on my website so I can't submit it directly but I want to capture those addresses

workhorse

Makes sense. I was able to get this to work with something like this:

<script>    
    var url = "https://SENDYDOMAIN/subscribe";
    var method = "POST";
    var postData = "api_key=APIKEY&email={{EMAIL DLV HERE}}&list=LIST ID";
    var shouldBeAsync = true;
    var request = new XMLHttpRequest();
    request.onload = function () {
       var status = request.status;
       var data = request.responseText;
    }   
    request.open(method, url, shouldBeAsync);
    request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    request.send(postData); 
</script>

In my tag, but you'll probably get lots of CORS errors so you'll need to add Access-Control-Allow-Origin response headers on the server where Sendy is installed to allow POST requests from the server where the form is. I'm also not a great JavaScript developer so there is probably / may be a better way than the above, it was adapted from Stack Overflow (I know, I know).

jacobrosenfeld

Thanks. Working except the CORS errors, how would I install Access-Control-Allow-Origin?

jacobrosenfeld

I think this answers that question: https://wesbos.com/mailchimp-to-sendy

workhorse

Great. If you have apache server, you'd edit your Sendy .htaccess file. You'd need to test, but I think you'd want:

Header set Access-Control-Allow-Origin: https://domain-with-form.com/
Header set Access-Control-Request-Method: POST

I just tested that and it worked for me.

jacobrosenfeld

I just edited the subscribe.php with this:
Header set Access-Control-Allow-Origin: https://domain-with-form.com/

jacobrosenfeld

This ends up creating a huge error_log file in /var/log, not sure why, I just end up deleting it every couple of days, but it ends up being like 200mb, not sure why. Any insight?

jacobrosenfeld

I think what happened was I updated Sendy and because I had only put that domain allow in the subscribe.php when I updated it my adjustment was lost, now I put it in the .htaccess and I think it's working