Search for communities.

        Helper function which takes from database only those communities which
        match search criteria. Uses parameter 'so' to set communities in the
        correct order.

        Parameter 'page' is introduced to restrict results and return only
        slice of them for the current page. If page == 0 function will return
        all communities that match the pattern.

def filter_communities(cls, p, so, with_deleted=False):
        """Search for communities.

        Helper function which takes from database only those communities which
        match search criteria. Uses parameter 'so' to set communities in the
        correct order.

        Parameter 'page' is introduced to restrict results and return only
        slice of them for the current page. If page == 0 function will return
        all communities that match the pattern.
        """
        query = cls.query if with_deleted else \
            cls.query.filter(cls.deleted_at.is_(None))

        if p:
            p = p.replace(' ', '%')
            query = query.filter(db.or_(
                cls.id.ilike('%' + p + '%'),
                cls.title.ilike('%' + p + '%'),
                cls.description.ilike('%' + p + '%'),
            ))

        if so in current_app.config['COMMUNITIES_SORTING_OPTIONS']:
            order = so == 'title' and db.asc or db.desc
            query = query.order_by(order(getattr(cls, so)))
        else:
            query = query.order_by(db.desc(cls.ranking))
        return query