Filtering via REST on calculated fields? Is it possible?

Questions and Answers
1

Hi all!

I have calculated field - added on the fly in overriden find/findOne methods in a controller.
This works fine for field creation and it is accessible on my front-end.
But, when I want to filter by the same field via REST parameter - it does not work - like the filter is not even there.

Is this even possible?

Adding calculated fields on the fly (findOne):

async findOne(ctx) {
		const { nulls } = ctx.request.query
		const { data, meta } = await super.findOne(ctx)
		if (data) {
			data.attributes.__properties = {
				...helpers.processTextProperties(data.attributes.text_properties),
			}
			data.attributes.__currentPrice = getCurrentProductPrice(modifyResponseBodyData(null, data.attributes))
			if (!nulls) removeNullProperties(data)
			removeKeys(data, config.KEYS_TO_REMOVE)
		}
		return { data, meta }
	}

Added value is object where one of the object attributes is “new_price”.

REST filter:
http://localhost:1337/api/products?fields=*&filters[$and][0][__currentPrice][new_price][$gte]=789&filters[$and][1][__currentPrice][new_price][$lte]=790&pagination[page]=1&pagination[pageSize]=24&sort[name]=asc

2

This should work if you print it out in the service does it give you the correct infromatoin?

3

Yes - i get this “calculated” field in response from server - JSON is exactly as expected.
But when using in filter - no dice. That is the problem.

4

I am not sure what the issue could be if it populates fine and it is not in a dynamic zone it should work

1 Like
5

I wonder if this could be cause by that old issue where filters are messed up with what current user can see (is allowed to see) - even though this should be public for front-end use? And since this is calculated field (or virtual as some call it) - could that be a problem? Quite odd behavior anyway.

6

Could be that the query is senatized out. you can test it by calling the sanitize query manualy and checking the output.
see the following code from the docs Controllers | Strapi Documentation

const { sanitize, validate } = require('@strapi/utils');

module.exports = {
  async findCustom(ctx) {
    const contentType = strapi.contentType('api::test.test');
    await validate.contentAPI.query(ctx.query, contentType, { auth: ctx.state.auth });
    const sanitizedQueryParams = await sanitize.contentAPI.query(ctx.query, contentType, { auth: ctx.state.auth });

    const entities = await strapi.entityService.findMany(contentType.uid, sanitizedQueryParams);

    return await sanitize.contentAPI.output(entities, contentType, { auth: ctx.state.auth });
  }
}
7

Already checked - as I said, the query returns everything as expected - JSON in response contains this new field as part of each product item/entity. It just does not want to filter by it.