Filter-out JSON objects into a new stream from REST end-point with webflux

Question

I want to filter-out Json objects from a REST end-point into a new - reduced stream of objects. I have a REST handler component that uses a WebClient to retrieve a Flux of JsonNode objects by providing a URI. For testing purposes I use dummy REST end-point.

The dummy JSON for mobiles product look like this:

{
   "products": [
       {
           "id": 1,
           "title": "iPhone 9",
           "description": "An apple mobile which is nothing like apple",
           "price": 549,
           "discountPercentage": 12.96,
           "rating": 4.69,
           "stock": 94,
           "brand": "Apple",
           "category": "smartphones",
           "thumbnail": "https://i.dummyjson.com/data/products/1/thumbnail.jpg",
           "images": [
               "https://i.dummyjson.com/data/products/1/1.jpg",
               "https://i.dummyjson.com/data/products/1/2.jpg",
               "https://i.dummyjson.com/data/products/1/3.jpg",
               "https://i.dummyjson.com/data/products/1/4.jpg",
               "https://i.dummyjson.com/data/products/1/thumbnail.jpg"
           ]
       },
       {
           "id": 2,
           "title": "iPhone X",
           "description": "SIM-Free, Model A19211 6.5-inch Super Retina HD display with OLED technology A12 Bionic chip with ...",
           "price": 899,
           "discountPercentage": 17.94,
           "rating": 4.0,
           "stock": 34,
           "brand": "Apple",
           "category": "smartphones",
           "thumbnail": "https://i.dummyjson.com/data/products/2/thumbnail.jpg",
           "images": [
               "https://i.dummyjson.com/data/products/2/1.jpg",
               "https://i.dummyjson.com/data/products/2/2.jpg",
               "https://i.dummyjson.com/data/products/2/3.jpg",
               "https://i.dummyjson.com/data/products/2/thumbnail.jpg"
           ]
       },
       …

In the test use-case I provide a criteria to filter out all JsonNode objects (smartphones) that received a rating score higher than 4.1. I want to be able to dynamically filter the response by providing a JSON path and criteria, but for testing purpose I hard code the path and criteria as following;

@Test
public void invokeGetJsonFluxResponseTest() {
        UriComponents uriComp = UriComponentsBuilder
                .newInstance().
                scheme(URI_SCHEME)
                .host(URI_HOST)
                .path(URI_PATH_PRODUCT_CATEGORY).build().encode();
        assertThat(uriComp.toUriString()).isNotEmpty();
        log.debug("URI: {}", uriComp.toUriString());
        Flux<JsonNode> result = restInokationHandler.invokeGetJsonFluxRespose(uriComp.toUri());

        result.doOnNext(node -> {
            if(node.path("/products/rating").asDouble() >= 4.1)
                log.debug(node.toPrettyString());
         
        }
        ).blockLast();
    }

I presume that my test function is consuming the stream since nothing is logged in the debug output. Who do I filter-out JSON objects from a Flux of JsonNode and collect them into a new stream?

I am using Spring Boot 3.

P.S. A similar question provides an answer by using Jackson2JsonDecoder and ObjectMapper to create a new stream.

Filter-out JSON objects into a new stream from REST end-point with webflux

0 Answers0