Best practice for dynamic filtering

1

Hello everyone,

I use Diesel in combination with a Rocket REST API and I’m wondering how I could achieve dynamic filtering.
For simplicity let’s assume I have to requests:

example.com/example?title=myexample
example.com/example?title=myexample&description=helloworld

The first request contains just a title and the second one a title + description:
The ideal query 1 would now look like:
SELECT * FROM example WHERE title=‘myexample’

The second query would be
SELECT * FROM example WHERE title=‘myexample’ AND description=‘helloworld’

2

Please add some code what you’ve already tried and where you hit an roadblock, otherwise it’s pretty hard to help you here. You probably want to look for into_boxed and BoxableExpression in our API doc’s there are examples how to build dynamic filters.

3

My finished query looks like this:

running_event::dsl::event
            .inner_join(
                organizer::dsl::organizer.on(organizer::id.eq(event::fk_organizer_id)),
            )
            .inner_join(
                event_category::dsl::event_category
                    .on(event_category::fk_event_id.eq(running_event::id)),
            )
            .inner_join(
                event_discipline::table.on(event_discipline::fk_event_id.eq(running_event::id)),
            )
            .inner_join(category::table.on(category::id.eq(event_category::fk_category_id)))
            .inner_join(discipline::table.on(discipline::id.eq(event_discipline::fk_discipline_id)))
            .select((
                event::title,
                event::description,
                event::target_date,
                event::deadline,
                event::address,
                event::postcode,
                event::city,
                organizer::title,
                organizer::email,
                organizer::address,
                organizer::postcode,
                organizer::city,
                organizer::phone,
                organizer::website,
                category::title,
                discipline::distance,
                discipline::fee,
                discipline::starttime,
                event_discipline::official,
            ));

Depending on the parameters in the query I have to filter for the following things:

.filter(event::target_date.ge(from_date).and(event::deadline.lt(to_date)))
.filter(event::postcode.eq(postcode))
.filter(discipline::distance.eq(distance))
.filter(category::title.eq(title))

But these filters have to be dynamic

Edit: Format

4

As mentioned above you want to look at the documentation of QueryDsl::into_boxed.