Record not persisted into R2DB using Spring boot webflux reactive

Question

I am trying to build an application using reactive. Initially i used to get proper response but after modifying the code, the record is not persisted into Database, but when I changed the logic to modify the response body, I see a success response but no record was found in DB nor I can see an error in logs.

Code before Modifying:

public Mono<ServerResponse> createCustomer(ServerRequest serverRequest) {
        return serverRequest.bodyToMono(Customer.class).flatMap(customer -> {
            ServerResponse.ok()
                .contentType(MediaType.APPLICATION_JSON)
                .body(customerRepository.save(customer), Customer.class);

        });
    }

But I want to return a generic API Response for all API calls and modified the code as below:

public Mono<ServerResponse> createCustomer(ServerRequest serverRequest) {
        Response response = new Response();
        return serverRequest.bodyToMono(Customer.class).flatMap(customer -> {
            saveCustomer(customer,apiResponse);
            return ServerResponse.ok()
                .contentType(MediaType.APPLICATION_JSON)
                .body(Mono.just(apiResponse), Response.class);

        }).doOnError(err -> {
                    log.error("Exception while creating customr record", err);
        }).onErrorResume(err ->  {
            apiResponse.setError(new Error(err.getMessage(),err.getCause()));
            return ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR)
                        .contentType(MediaType.APPLICATION_JSON)
                        .body(Mono.just(apiResponse), ApiResponse.class);
        });
    }

    public Response saveCustomer(Customer customer,Response apiResponse){
        customerRepository.save(customer);
        apiResponse.setCode("0");
        apiResponse.setMessage("Successfully Created customer");
        return apiResponse;
    }

Any thoughts are appreciated please.

Answer 1

I doubt this code - customerRepository.save(customer);

If you are using R2DBC, the save method does not save directly. It will return a publisher type. It has to be subscribed to make it work. Otherwise it will not insert records.

You need to do this!

customerRepository.save(customer).subscribe();

However this is NOT a good practice to directly subscribe like this. Instead you should do something like this.

public Mono<Response> saveCustomer(Customer customer,Response apiResponse){
    return customerRepository.save(customer)
             .map(c -> {
                  apiResponse.setCode("0");
                  apiResponse.setMessage("Successfully Created customer");
                  return apiResponse;
              });
}

then modify your

return serverRequest.bodyToMono(Customer.class).flatMap(customer -> {.....

code to something like this.

return serverRequest.bodyToMono(Customer.class)
                     .flatMap(customer -> saveCustomer(customer, response))
                     .flatMap(r -> ServerResponse.ok()
                                 .contentType(MediaType.APPLICATION_JSON)
                                 .body(Mono.just(r), Response.class))