Help with cursor based paging

[tbirnseth]

I'm trying to use the newer cursor based paging.  I use a url similar to:

store/admin/api/2019-07/products.json?limit=5

The headers returned with after the call to the api have:

x-shopify-shop-api-call-limit: 1/40
x-shopify-api-version: 2019-07
link: ; rel="next"

There is no 'page_info' parameter for me to use to get the next page of results.  And how do I use a 'rel' attribute in an API call?  Is this passed as a 'rel' header?

Be really helpful if someone could post a code segment of looping through some pages.  The docs don't make a lot of sense to me since the response headers in the docs don't match the response headers from the api.

I'd think it would be something like:

$link_info='';
do {
  $new_data = Http:get("shop/admin/api/2019-07/products.json?limit=5".($link_info?"&page_info=$link_info":'') );
  $link_header = getLinkHeader();
  $link_info= $link_header;  // should contain something like page_info=xyz&rel=next
  if( $new_data )
    processNewData($new_data);
} while(!empty($new_data));