class Listing(Master):
    '''
    Member listing view. This demonstrates how to require a permission to view, and also how to
    obtain a list of annotated principals.
    '''

    grok.require('logindemo.ViewMemberListing')

    def fieldNames(self):
        return (f for f in IUser)

    def members(self):
        pau = getUtility(IAuthentication)
        principals = pau['principals']
        roster = []
        for id in sorted(principals.keys()):
            # adapt the principals to IUser to get all fields
            user = IUser(principals[id])
            fields = {}
            for field in IUser:
                fields[field] = getattr(user, field)
            roster.append(fields)
        return roster