Check if user has permissions to upload file to SharePoint folder using PnP Core

Question

We have a C# Windows application that uses PnP Core to interact with SharePoint files.

We have a function in our app that uploads files to a SharePoint folder that the user selects. At the moment, we are catching any permission-related issues during the file upload process.

Is there a way to check if the user has permissions to upload a file to the selected SharePoint folder, BEFORE attempting to upload it?

We started looking at the specific SharePoint permissions / roles of the user, but we were not sure if that was the best path, or also what to actually look for.

Answer 1

You will need to check if the user has access to the folder. Essentially the user should have "Microsoft.SharePoint.Client.PermissionKind.AddListItems" at the folder level.

Here is a code sample for CSOM (you will need to adapt if using PnP):

User oUser = cilentContext.Web.CurrentUser;
ListItem oItem = cilentContext.Web.GetFolderByServerRelativePath('path_to-folder');
cilentContext.Load(oItem);
cilentContext.Load(oUser);
cilentContext.ExecuteQuery();
var oPermissions = oItem.GetUserEffectivePermissions(oUser.LoginName);
cilentContext.ExecuteQuery();
if (oPermissions.Value.Has(Microsoft.SharePoint.Client.PermissionKind.AddListItems))
{
    return true;
}
else
{
     return false;
}