Can add-in get context for host web's site collection root web?

[Joseph Ackerman]

I know that I can access my host web from my add-in web using a SharePoint hosted add-in, but is there any way to get the context for the root site of site collection containing the host web?  

This add-in may be installed in multiple sub-sites of the same site collection and I would like all of the installations to share some of the resources by storing them in the root web of the site collection (so I don't have multiple copies of this floating around in every site that uses the add-in).

I've been unable to locate any disucssion of this anywhere.  Thanks.

[#2 · Accepted solution]

You can as long as your app has been granted the required site collection scoped permissions. 

Here's some demo code I wrote that shows how to build your context

var rootWeb;

    function getSiteCollectionTitle() {
        var scServerRelativeUrl = _spPageContextInfo.siteServerRelativeUrl;
        var clientContext = new SP.ClientContext(scServerRelativeUrl);
        rootWeb = clientContext.get_web();

        clientContext.load(rootWeb);
        clientContext.executeQueryAsync(onSuccess, onFail);
    }
    function onSuccess() {
        alert('Title of Root Web:' + rootWeb.get_title());
    }
    function onFail(sender, args) {
        alert('Error: ' + args.get_message());
    }

[#3]

>>You can as long as your app has been granted the required site collection scoped permissions. <<

That makes sense.  I should be okay in this instance because the Add-in will only be available to install and run by Site Admins with Full Control of the site collection.

Thanks very much for this -- looks like this will be very helpful for me!

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