Searching by product price range and receiving a list of items whose price falls in that range (Java)

In this use case, the user enters the price range before searching for a product. This can be combined with any other use case that results in a list of items

Code snippets

Client calls the BAP server to trigger search:

    @PostMapping("/local_retail/search_by_product_price")
    public ResponseEntity searchByProductPrice(
            @RequestHeader HttpHeaders headers,
            @RequestBody ClientSearchRequest request) {
        var response = bapApplicationService.generateSearchRequest(request, headers);
        return ResponseEntity.ok(response);
    }

BAP server generates the protocol request body

/*
Example Request JSON:
{
    "context": {
        "domain": "local_retail",
        "country": "IND",
        "city": "std:080",
        "action": "search",
        "core_version": "0.9.2",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "transaction_id": "1239890342",
        "message_id": "123793824",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "intent" : {
            "item": {
                "price" : {
                    "currency": "INR",
                    "minimum_value": "50",
                    "maximum_value": "300"
                }
            },
            "fulfillment": {
                "end": {
                    "location": {
                        "gps": "12.4535445,77.9283792"
                    }
                }
            }
        }
    }
}``
*/

    public Response generateSearchRequest(ClientSearchRequest request, HttpHeaders headers) {

        var messageId = UUID.randomUUID().toString();

        // Check and create transaction id if not passed
        var txnId = StringUtils.hasText(request.getTransactionId())
                ? request.getTransactionId()
                : UUID.randomUUID().toString();

        // Construct the request
        var context = Context.builder().domain(request.getDomain())
                .action(Context.ActionEnum.search)
                .messageId(messageId)
                .transactionId(txnId)
                .transactionId(UUID.randomUUID().toString())
                .timestamp(new Date().toString())
                .build();
        var intentBuilder = Intent.builder();

        // Construct item object for the request from product's price
        intentBuilder = intentBuilder.item(ClientAssembler.of(request.getItem()));

        var searchRequest = SearchRequest.builder()
                .context(context)
                .message(SearchMessage.builder()
                        .intent(intentBuilder.build()).build()).build();

        return invokeSearch(searchRequest, headers);
    }
}

BAP server calls protocol search to the network

    public Response invokeSearch(SearchRequest request, HttpHeaders headers) {

        // Call to look up function which returns the the public key and BPP/BG Endpoint to be called
        var url = lookUp(headers);

        //Call BPP Search api
        var searchResponse = apiClient.post(url[0] + Context.ActionEnum.search,
                constructRequestHeaders(),
                request,
                Response.class);
        if (responseEntity.getBody() == null || responseEntity.getBody().getError() != null ||
                "NACK".equals(responseEntity.getBody().getMessage().getAck().getStatus())) {
            // Return custom error to the client
            return null;
        }
        return searchResponse.getBody();
    }

BAP receives protocol on_search

/*
Example Response JSON:
{
    "context": {
        "domain": "nic2004:52110",
        "country": "IND",
        "city": "std:080",
        "action": "on_search",
        "core_version": "0.9.1",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "bpp_id": "https://mock_bpp.com/",
        "bpp_uri": "https://mock_bpp.com/beckn/",
        "transaction_id": "1209849124",
        "message_id": "12341242343",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "catalog": {
            "bpp/descriptor": {
                "name": "Mock BPP"
            },
            "bpp/providers": [
                {
                    "id": "pooja-stores",
                    "descriptor" : {
                        "name": "Pooja Stores"
                    },
                    "locations": [
                        {
                            "id": "koramangala-4th-block-location",
                            "gps": "12.9349377,77.6055586"
                        }
                    ],
                    "categories": [
                        {
                            "id": "fresh_fruits",
                            "descriptor": {
                                "name": "Fresh Fruits"
                            }
                        },
                        {
                            "id": "beverages",
                            "descriptor": {
                                "name": "Beverages"
                            }
                        },
                    ],
                    "items": [
                        {
                            "id": "item_2",
                            "descriptor" : {
                                "name" : "Green Apples Organic",
                                "images" : [
                                    "https://mock_bpp.com/images/item_2.jpg"
                                ]
                            },
                            "category_id": "fresh_fruits",
                            "location_id": "koramangala-4th-block-location",
                            "price" : {
                                "currency": "INR",
                                "value": "170"
                            },
                            "matched": true
                        },
                        {
                            "id": "item_1",
                            "descriptor" : {
                                "name" : "Red Apples",
                                "images" : [
                                    "https://mock_bpp.com/images/item_1.jpg"
                                ]
                            },
                            "category_id": "fresh_fruits",
                            "location_id": "koramangala-4th-block-location",
                            "price" : {
                                "currency": "INR",
                                "value": "90"
                            },
                            "related": true
                        },
                        {
                            "id": "item_7",
                            "descriptor" : {
                                "name" : "Green Apple Juice",
                                "images" : [
                                    "https://mock_bpp.com/images/item_7.jpg"
                                ]
                            },
                            "category_id": "beverages",
                            "location_id": "koramangala-4th-block-location",
                            "price" : {
                                "currency": "INR",
                                "value": "70"
                            },
                            "matched": true
                        },
                    ]
                },
                {
                    "id": "food-mall",
                    "descriptor": {
                        "name": "Food Mall"
                    },
                    "locations": [
                        {
                            "id": "food-mall-location",
                            "gps": "12.9349377,77.6055586"
                        }
                    ],
                    "categories": [
                        {
                            "id": "fresh-food": {
                                "name": "Fresh food"
                            }
                        }
                    ],
                    "items": [
                        {
                            "id": "item_1_1",
                            "descriptor" : {
                                "name" : "Green Apple Salad",
                                "images" : [
                                    "https://mock_bpp.com/images/item_1_1.jpg"
                                ]
                            },
                            "category_id": "fresh-food",
                            "location_id": "food-mall-location",
                            "price" : {
                                "currency": "INR",
                                "value": "200"
                            },
                            "matched": true
                        }
                    ]
                }
            ],
            "bpp/fulfillments": [
                {
                    "type": "home-delivery"
                }
            ]
        }
    }
}
*/
    @PostMapping("/bap/on_search")
    public ResponseEntity onSearch(
            @RequestHeader HttpHeaders headers,
            @RequestBody OnSearchRequest request) {
        var response = bapCallbackApplicationService.onSearch(request, headers);
        return ResponseEntity.ok(response);
    }

    public Response onSearch(OnSearchRequest request, HttpHeaders headers) {
        // Validate the headers received
        var isHeadersValid = validateHeaders(headers);
        // Construct and return error if the received headers are invalid
        if (!isHeadersValid) return null;

        // Store the data received based on message id for the client to poll
        saveToDB(request);

        return Response.of("ACK", null);
    }

Client polls BAP to get the on_search results

    // Endpoint for the client to poll the search data based on the message id
    @GetMapping("/local_retail/on_search")
    public ResponseEntity searchByMessageId(
            @PathVariable(ClientRoutes.PARAM_MESSAGE_ID) String messageId,
            @RequestHeader HttpHeaders headers) {
        var data = bapApplicationService.get(messageId);
        return ResponseEntity.ok(data);
    }