def paginate(
query,
model,
descending=False,
page_token=None,
limit=50,
sort_field_alias=None,
max_page=None,
sort_field_name=None,
):
"""
Paginates the given query using an field range, starting at the optional page_token.
Returns a *list* of matching results along with an unencrypted page_token for the next page, if
any. If descending is set to True, orders by the field descending rather than ascending.
"""
# Note: We use the sort_field_alias for the order_by, but not the where below. The alias is
# necessary for certain queries that use unions in MySQL, as it gets confused on which field
# to order by. The where clause, on the other hand, cannot use the alias because Postgres does
# not allow aliases in where clauses.
sort_field_name = sort_field_name or "id"
sort_field = getattr(model, sort_field_name)
if sort_field_alias is not None:
sort_field_name = sort_field_alias
sort_field = SQL(sort_field_alias)
if descending:
query = query.order_by(sort_field.desc())
else:
query = query.order_by(sort_field)
start_index = pagination_start(page_token)
if start_index is not None:
if descending:
query = query.where(sort_field <= start_index)
else:
query = query.where(sort_field >= start_index)
query = query.limit(limit + 1)
page_number = (page_token.get("page_number")
or None) if page_token else None
if page_number is not None and max_page is not None and page_number > max_page:
return [], None
return paginate_query(query,
limit=limit,
sort_field_name=sort_field_name,
page_number=page_number)