Assign Users To Groups Using Hominid

When it comes to integrating MailChimp into Rails applications, Hominid is my gem of choice. It’s implementation is relatively straightforward and it stays true to the MailChimp API.

I rarely have issues with it, but I recently needed to funnel users into specific groups which were part of a list and hit a bit of snag with the merge vars parameter of the listSubscribe function.

The API clearly states:

Each element in this array should be an array containing the “groups” parameter which contains a comma delimited list of Interest Groups to add.

And I was attempting to implement it like this:

h.list_subscribe 'my_list_id', user_email, { :GROUPINGS => [ 'name' => 'myGroup', 'groups' => group.name ] }, 'html', false, true, true, false

Notice that I’m passing the merge vars in as a hash and assigning an array to GROUPINGS. But as the API clearly states (and I obviously misread), GROUPINGS should reference an array that contains an array.

But the correct way to assign users to groups using Hominid is:

h.list_subscribe 'my_list_id', user_email, { :GROUPINGS => [ { 'name' => 'myGroup', 'groups' => group.name } ] }, 'html', false, true, true, false

Thought I’d share this just in case anyone else on the planet happens to hit the same snag I did.