I’m quite new to WordPress – and coding in general except I did a lot of SQL, R Matlab etc during my studies a long time ago so I can learn if I know where to search :-). But php, javascript etc are pretty new to me.

I have an “assignment” I don’t know where to start with:

I want to use Mailster to send emails because it can display custom tags to users (documentation here: https://kb.mailster.co/add-custom-dynamic-tags-to-your-newsletter/)

I would want to send users their own referral link / code at the bottom of my first campaign. The referral code is generated by WPGens https://wpgens.helpscoutdocs.com/.

Here is an example that they give to generate a promo code –

function get_subscribers_coupon( $subscriber_id ) {
$seed = AUTH_SALT;
$length = 10;
$code = substr( strtoupper( base_convert( md5( $seed . $subscriber_id 
), 16, 36 ) ), 0, $length );
return $code;

mailster_add_tag( 'coupon', function( $option, $fallback, $campaignID = 
null, $subscriberID = null ) {

// make sure the subscriber ID is set
if ( ! is_null( $subscriberID ) ) {
    return get_subscribers_coupon( $subscriberID );

// return the fallback "NOCOUPONCODE4U"
return $fallback;
} );

Regarding my specific problem, from what I can see the referral code I need to return is stored in my wp_usermeta table with one line per user id, meta_key = “gens_referral_id” and meta_value = the_referral_code that I want to show in the newsletter – https://monosnap.com/file/j3zuxY65c4EBs8tG6rWv23X1Fhq90B

Do I need to query the table from a php function? Or do theses user meta tags live somewhere else? Could you help me writing the function to return this as a custom dynamic tag?

More generally I wonder how you guys test the php code that you write, how you know the variables you can pull from etc?

Thanks so much!! Reynald

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