How to pull data fields from Document Sets within an Asset Library?

Question

I have an Asset Library with document sets, that I need to pull data from. I'm able to pull data from using the following code, but not sure how to get and enumerate data from the associated document set.

//gumdropsgc.sharepoint.com/sites/Training/_api/web/lists/getbytitle('Modules')/items
//gumdropsgc.sharepoint.com/sites/Training/_api/web/lists/getbytitle('Modules')/items(1)

<script type="text/javascript">
    $.ajax({
        url: "https://gumdropsgc.sharepoint.com/sites/Training/_api/web/lists/getbytitle('Modules')/items(1)/Additional Content",
        type: "GET",
        headers: {"Accept": "application/json;odata=verbose"},
        cache:false,                
        success: function(data){
            console.log(data);
            var html = "<table border='0'>";
            $(data.d.results).each(function(){
                html = html + "<tr><td>" + this.Title + "</td></tr>" +
    "<tr><td><h2>" + "Roles           :" + "   " + this.Roles + "</h2></td></tr>";
            });
            html += "</table>";
            $("#listResult").html(html)
        }
    });
    </script>

    <div id="listResult"></div>

Answer 1

Document Set you can treat as a Folder in the Document Library.

Hence for listing those you should use the Files EndPoint. Something like

https://gumdropsgc.sharepoint.com/sites/Training/_api/web/lists/getbytitle('Modules')/Files

The above query will give you all Files in that Library. For targeting a particular folder you can use Children.

More on accessing Files using REST API https://msdn.microsoft.com/en-us/office/office365/api/files-rest-operations