WordPress Shortcode for iFrame code

We are building a series of WP sites that use [login to view URL] chat question, polling, widget. [login to view URL] We set up an event and it is embedded via iFrame. We have been embedding them one by one using WP iFrame plugin and manually entering the embed code. We need a shortcode that will render the proper iFrame, along with query string information to pass over the logged in user's Display Name / Full Name. (All users visiting the page will be logged in, no guests) Here is information on passing query parameters via [login to view URL] For example, I can get this to work by itself. <iframe src="[login to view URL]" height="100%" width="100%" style="min-height: 560px;"></iframe> But, "JohnDoe" has to equal the logged-in user's "First LastName". I've tried <? PHP echo $username: ?> but that doesn't work and is probably not correct (which is why I'm coming here) We need control over the EventID and the min-height. So, at the end of the day, The shortcode would be something like this [slido event=XXXXXXXX min-height=600px]