Automatically generate filterset_class for snippets and generic IndexView through list_filter

[laymonage]

As part of wagtail/rfcs#85.

This PR adds a get_filterset_class on the generic IndexView that automatically generates a WagtailFilterSet subclass with the fields defined in IndexView.list_filter. The API is also surfaced in the SnippetViewSet class to ease customisation for Snippets' IndexView.

For Snippets' IndexView, the get_filterset_class() method works by calling SnippetViewSet.get_filterset_class() first. If the result is None, it then falls back to the generic IndexView.get_filterset_class() implementation where the class is dynamically generated if necessary.

Please check the following:

• Do the tests still pass?¹
• Does the code comply with the style guide?
  • Run make lint from the Wagtail root.
• For Python changes: Have you added tests to cover the new/fixed behaviour?
• For new features: Has the documentation been updated accordingly?

Please describe additional details for testing this change.

Continuing from the test example in #10241.

from wagtail.snippets.models import register_snippet
from wagtail.snippets.views.snippets import SnippetViewSet


class PersonViewSet(SnippetViewSet):
    icon = "user"
    list_per_page = 2
    chooser_per_page = 1
    admin_url_namespace = "some_namespace"
    base_url_path = "deep/within/the/admin"
    chooser_admin_url_namespace = "my_chooser_namespace"
    chooser_base_url_path = "choose/wisely"
    # this will generate exact filters
    list_filter = ["job_title", "first_name"]
    # alternatively, this will generate filters with lookups
    list_filter = {
        "job_title": ["contains"],
        "first_name": ["contains"],
        "first_published_at": ["date"],
    }



register_snippet(Person, viewset=PersonViewSet)

Footnotes

1. Development Testing ↩

[squash-labs]

Manage this branch in Squash

Test this branch here: https://laymonagecustom-snippets-list-ss8iq.squash.io

[laymonage]

Hold on, I haven't added docs in the topics/snippets.md file.

[laymonage]

Ok, docs added.

[gasman]

All looks good to me!

[gasman]

Looks like this file needs renumbering - will do that while I merge.

[gasman]

Merged in a3498b2