In LimitOffsetPagination limit=0 should revert to default limit.

[lovelydinosaur]

Treat limit=0 in the same way as an other invalid amount in thelimit` parameter.

[lovelydinosaur]

Closes #3990.
Closes #3444.

Not that this also removes a now defunct test, that it would return empty results. (Which didn't cover the DivideByZero that it also causes elsewhere.)

[lovelydinosaur]

Thanks to @mitar and @nhorelik for the input on this! 😄

[mitar]

Hm, but with this change it is not possible to ask for maximum allowed number of requests? Client has to know how much is that.

[lovelydinosaur]

I don't think 0==max is particularly intuitive behavior. If someone wants that, then sure override the class and use your own desired behavior. Treating 0 the same as any other invalid value seems a pretty reasonable default.

[kevin-brown]

Hm, but with this change it is not possible to ask for maximum allowed number of requests?

There's a note in the docs about how you might go about doing this.

http://www.django-rest-framework.org/api-guide/pagination/#drf-extensions

The DRF-extensions package includes a PaginateByMaxMixin mixin class that allows your API clients to specify ?page_size=max to obtain the maximum allowed page size.

[mitar]

Hm, what is difference between max_limit and max_page_size?

[mitar]

So it seems that that extension works only when you have pagination, not when you have offset/limit approach. But maybe a similar mixin can be make for offset/limit as well.

[stschindler]

Unfortunately this prevents my frontend client to get the count of a particular resource. What I've been doing is sending a GET request to /resource?limit=0 to fetch the total amount of existing records.

Is there any other good way of doing that?

[yli-cpr]

This breaks old behavior. Clients may have been using ?limit=0 to count objects. Is there any benefit of treating zero as invalid input?

[carltongibson]

...old behaviour...

That's quite old 😀 v3.4 was mid-2016.

A work around would be to subclass LimitOffsetPagination to check for 0 in get_limit before calling super.

[yli-cpr]

Thanks. I am doing a similar workaround.

[crazy-canux]

How did you guys fix this?
I upgrade from 3.3 to 3.8, but frontend use &limit=0 not working.