Add generic archive views for objects with DateRangeFields

[Bence Nagy]

Currently Django has generic views such as MonthArchiveView for rendering a list of objects with a date field's value falling within a given timeframe.

Generic views such as this would be rather useful for objects whose place in time is determined with a date range, instead of a single date, such as subscription invoices specifying the dates covered, or multiple day events (say, a set of conferences).

[Tim Graham]

Marc, what's your opinion about adding generic views to contrib.postgres?

[Marc Tamlyn]

The behaviour of this would have several possible options, and I don't think it's a generic enough use case to deserve Django maintaining it. What happens when the range spans two months/years? Does it appear in both? Only one? If one based on what, start? end?

As a side note, I *think*, though I'm not completely sure, that the existing archive views can be used in the "only one" case by:

• Setting date_field = 'range__start'
• Overriding uses_datetimefield if you are using a DateTimeRangeField
• Overriding ordering until such a time as transforms are supported in order by clauses (hopefully forthcoming).

For the "overlaps" case, a lot more work would be needed. At present the implementation of the archive views assumes a fixed point in time, and that every object would appear in only one view. For example, getting the list of possible sub views (month views for a year) which are non empty is a much harder process.

So, one possible use case is (nearly) covered by the built in view. The second is largely different, but could definitely live in a third party package. I'd rather keep contrib.postgres for database things and their form fields rather than adding any possible related concept.