Module list_params 

Shared list-endpoint query-parameter helpers — one place that owns the reserved-key skip list, ?ordering= parsing and ?page_size= clamping, so viewset::handle_list and template_views::ListView cannot drift apart. Query-parameter parsing shared by list endpoints.

viewset::handle_list and the ListView CBV read the same parameters: ?page=N, ?ordering=col, ?search=term, and the model’s own filter keys. This module holds the parts they must agree on:

• RESERVED_LIST_KEYS / is_reserved_list_key — parameters that control paging, sorting and search, so they are never filters.
• parse_ordering — splits ?ordering=col,-col2.
• clamp_page_size — resolves ?page_size=N.
• parse_page / page_offset — ?page=N and its overflow-safe offset.
• split_in_list — a __in value, capped at MAX_IN_VALUES; in_values_budget caps all lists of a request together.

Each layer still builds its own WHERE clause, because viewset supports a richer filter syntax than the CBV.

Enums

InListTooLong

A __in list longer than MAX_IN_VALUES, or __in lists whose sum passes in_values_budget.

Constants

MAX_IN_VALUES

Most values one ?field__in= list may carry. Far under every dialect’s bind limit, so a long list is a 400, not a driver error (#1865).

RESERVED_LIST_KEYS

Query keys that control paging, sorting and search. A list handler must never treat one of these as a model filter, even if a column has the same name.

Functions

clamp_page_size

Work out the page size from ?page_size=N.

in_values_budget

Most __in values one request may carry over all its lists, so a dialect with max_bind_params binds gets a 400 rather than a driver 500.

is_reserved_list_key

true when key is one of RESERVED_LIST_KEYS. Use it to skip these keys before parsing filters:

page_offset

Row offset of 1-based page. Saturates, so a huge page is an empty page rather than a wrapped negative OFFSET (#1865).

parse_ordering

Parse ?ordering=col,-col2,col3 into OrderItems. A leading - means descending.

parse_page

?page=N, 1-based. Missing, garbage, zero or negative gives page 1.

split_in_list

Split a comma-separated __in value, dropping empty entries. Stops reading past the cap, so a 2 MB body is not split in full.