JSON_API: How best to expose an aggreate value in a GET or READ endpoint

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1

I’m still not 100% with my understanding of the JSON_API layers on Ash.

I’ve created an easy and working aggregate to count the number of related (to_many) records on a resource.

But… I’d like to insert that aggregate value into the JSON api response for gets & reads. I’m currently doing that using the previously learned metadata approach - but I’m curious whether there is a better way to do this.

While I’m at it… Are aggregates the best way to go or should I be using some other form of calculated attributes instead.

Thanks
Martin

2

Ah, so metadata is not necessary for this.

You can use the fields query parameter to include public aggregates (i.e aggregates with public?: true. For example fields[type]=agg_name,other,fields. If you want the aggregate to be included by default, you can set default_fields on the route or the resource level, i.e

default_fields [:the, :list, :of, :fields, :agg_name]

That will make them appear as standard attributes in the response.

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3

That’s perfect. Many thanks. The trick (at least to me) was to make the aggregate public and to add it manually to he fields list - or fall back (with no fields list) to the default_fields list.

Thanks again. I’m slowly getting there - step by step.

Martin

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