Theme API: make {{nextpost}} {{prevpost}} available to themes

[ErisDS]

We need to have some way to get hold of all the details of the next and previous post on the post page.

This means providing access to all properties of those two models through something like

{{#nextpost}}
{{title}}
{{/nextpost}}

[ErisDS]

Anyone got any clever ideas for how to do this?

ATM I'm thinking one of:

• the single controller is just going to have to do 2 extra queries.
• the helper is an async helper and does the query itself.

In the former, every post page does 2 extra fetches for data, forever. Even though we will have caching, that's a bit bleh.

In the latter, content gets loaded in dynamically and only when it's actually requested - but over ajax which will be a slower request I guess. Also makes it harder to know where what came from when, and I don't think it will be as usable.

Any other ideas?

[ErisDS]

So I decided to go with just loading the 2 extra posts on every post page. This way, it's just data that is available by default and not a handlebars helper.

The problem with doing this is building the query as at the moment I can't find a way to pass anything other than straight '=' style where clauses, other operators require 3 args. If we upgrade to bookshelf 0.2.5 we get a function syntax which is useful, but basically, we need to rejig findPage quite a lot, into our own dynamic interface to query builder. That is, create a way we can define complex arguments in JSON and then have findPage call relevant query builder functions with each argument. The JSON -> query builder stuff should probably be a base function so we can use it later for building fancy queries for other objects.

This will be a separate issue, which this issue will depend on.

Punting to 0.4 for now.

[ErisDS]

I think it should be possible to revisit this now that knex properly supports subqueries.

[ErisDS]

Closing in favour of #4262