Update SharedWithUsersId REST API

Question

I've been looking at the REST API to update fields in SharePoint. I can get it to update the title without any problems, however when I go to update the SharedWithUsersId they do not update. I don't get any errors or success messages when running an update. This is the JSON I am posting to the service:

{
    "__metadata": {
        "type": "SP.Data.DocumentsItem"
    },
    "Title": "Default Value",
    "SharedWithUsersId": {
        "__metadata": {
            "type": "Collection(Edm.Int32)"
        },
        "results": [
          11,
          14,
          15,
          22
        ]
    }
}

Am I missing something or is it even possible? The credentials being passed are for a Global Administrator which has access to the library.

Answer 1

After digging a little deeper this is how you can share an item.

http://msdn.microsoft.com/en-us/library/office/dn495392(v=office.15).aspx

Sharing a file can be done like so, also a folder as this can be treated as an item

/_api/Web/Lists(guid'guid of list')/Items(4)/roleassignments/addroleassignment(principalid=1,roledefid=1073741827)