My configuration is here
#Configuration
class TemplateConfiguration {
#Bean
fun templateResolver(): StringTemplateResolver? {
val templateResolver = StringTemplateResolver()
templateResolver.templateMode = TemplateMode.TEXT
return templateResolver
}
#Bean
#Primary
fun templateEngine(): SpringWebFluxTemplateEngine {
var engine = SpringWebFluxTemplateEngine()
engine.setTemplateResolver(templateResolver())
return engine
}
}
and
var books = Flux.fromArray(arrayOf(Book( ....), Book(....))
var context = Context()
var streamData = ReactiveDataDriverContextVariable(books, 10)
context.setVariable("books", streamData)
// then something like below
engine.process(template, context)
Error message is:
org.thymeleaf.templateparser.text.TextParseException: Exception evaluating SpringEL expression: "book.price" (template: "[# th:each="book: ${books}"] - [(${book.price})] [/]"
......
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'price' cannot be found on object of type 'org.thymeleaf.spring5.context.webflux.ReactiveDataDriverContextVariable' - maybe not public or not valid?
......
I think it's a problem that the Flux Stream was not delivered properly.
How can i solve this?
Plz help me and I apologize in advance for the poor of my English.
I'm not sure this is a solution (maybe is a workaround??)
I use collectList().map instead of ReactiveDataDriverContextVariable
then it worked
var books = Flux.fromArray(arrayOf(Book( ....), Book(....))
var context = Context()
books.collectList()
.map { list ->
context.setVariable("books", list)
engine.process(template, context)
}
It's a some kind of monologue ^^;;;
Related
Hello recently started studying Webflux.
And sometimes I encounter the tasks that you need to form a simple DTO and return it
Take for example the usual class dto
#Data
#Builder
public static class Dto {
private long id;
private String code1;
private String code2;
}
And a primitive service with two methods...
#Nullable Mono<String> getCode1(long id);
#Nullable String getCode2(long id);
And wrote a method that forms at the output of Mono
private Mono<Dto> fill(long id) {
var dto = Dto.builder()
.id(id)
.build();
//doOnNext
var dtoMono1 = service.getCode1(id)
.map(code -> {
dto.setCode1(code);
return dto;
})
.doOnNext(innerDto -> innerDto.setCode2(service.getCode2(id)));
//map
var dtoMono2 = service.getCode1(id)
.map(code -> {
dto.setCode1(code);
return dto;
})
.map(unused -> service.getCode2(id))
.map(code -> {
dto.setCode1(code);
return dto;
});
//just
var dtoMono3 = Mono.just(dto)
.flatMap(innerDto -> service.getCode1(innerDto.getId()));
//just
var dtoMono4 = Mono.fromCallable(() -> dto)
.subscribeOn(Schedulers.boundedElastic())
.flatMap(innerDto -> service.getCode1(innerDto.getId()));
}
QUESTION:
Is it possible to simply create DTO and use it in the Webflux call
chain ... Or I need to wrap it in mono.just or mono.fromcallable
(what are the pros and cons)
How best to fill in values via doOnNext
or through MAP. An extra line (Return DTO) appears in the case of
MAP and some people also told me if for example NULL comes, doOnNext will
miss it and go further to fill up current dto. But on the other, the MAP is used
to transform the object, and the doOnNext is more for debugging and
logging
Thanks you...
How about using zip operator in such a case?
I hope this example can help you:
private Mono<Dto> fill(long id) {
return Mono.zip(someService.getCode1(id), Mono.just(someService.getCode2(id)))
.map(tuple ->
Dto.builder()
.id(id)
.code1(tuple.getT1())
.code2(tuple.getT2())
.build()
);
}
I already have this Java Configuration:
#Configuration
public class FAPIAutoConfiguration {
private static final String INTERACTION_ID = "x-fapi-interaction-id";
private final BaggageField fapiBaggageField = BaggageField.create(INTERACTION_ID);
#Bean
BaggagePropagationCustomizer baggagePropagationCustomizer() {
return builder -> builder.add(SingleBaggageField.
remote(fapiBaggageField));
}
#Bean
CorrelationScopeCustomizer correlationScopeCustomizer() {
return builder -> builder.add(SingleCorrelationField.create(fapiBaggageField));
}
}
And the propagation in a Webflux application works, but I would like to know what is the best way to initialize the baggage if it is not present in the request headers. I mean, if the header is missing, generate a value and propagate this one.
I ended up adding a TracingCustomizer to the above configuration to fill the value when is missing in that context.
#Bean
TracingCustomizer tracingCustomizer(UniqueIdGenerator generator) {
return builder -> builder.addSpanHandler(new SpanHandler() {
#Override
public boolean begin(TraceContext context, MutableSpan span, TraceContext parent) {
var value = fapiBaggageField.getValue(context);
if (value == null) {
fapiBaggageField.updateValue(context, generator.next());
}
return super.begin(context, span, parent);
}
});
}
I do not know if this is the best option yet
As described on the Google Cloud Functions docs, it is possible to trigger a Function based on Firebase Realtime Database events (write/create/update/delete).
The following docs sample explains how to get the delta snapshot.
public class FirebaseRtdb implements RawBackgroundFunction {
private static final Logger logger = Logger.getLogger(FirebaseRtdb.class.getName());
// Use GSON (https://github.com/google/gson) to parse JSON content.
private static final Gson gson = new Gson();
#Override
public void accept(String json, Context context) {
logger.info("Function triggered by change to: " + context.resource());
JsonObject body = gson.fromJson(json, JsonObject.class);
boolean isAdmin = false;
if (body != null && body.has("auth")) {
JsonObject authObj = body.getAsJsonObject("auth");
isAdmin = authObj.has("admin") && authObj.get("admin").getAsBoolean();
}
logger.info("Admin?: " + isAdmin);
if (body != null && body.has("delta")) {
logger.info("Delta:");
logger.info(body.get("delta").toString());
}
}
}
The sample works perfectly but the question is: How can I deserialize this delta to a POJO?
I tried:
val mObject = gson.fromJson(body.get("delta").toString(), MyCustomObject::class.java)
But I am getting:
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT
As far as I know it is because MyObject class has a List<T> field, and Firebase Database always convert Lists to Maps with integer keys.
I preferably do not want to change every List<T> to Map<Int,T>, because I have a lot of classes :(
Thanks in advance!
So, here is what I ended up doing (maybe not the best solution!):
1) Create a custom Json Deserializer for Firebase-coming lists:
class ListFirebaseDeserializer<T> : JsonDeserializer<ArrayList<T>> {
override fun deserialize(json: JsonElement?, typeOfT: Type?, context: JsonDeserializationContext?): ArrayList<T> {
val result = ArrayList<T>()
val typeOfElement = (typeOfT as ParameterizedType).actualTypeArguments[0]
json?.let {
json.asJsonObject.entrySet().forEach {
entry->
result.add(Gson().fromJson(entry.value, typeOfElement))
}
}
return result
}
}
This takes the lists that Firebase turned into maps and convert it back to actual lists.
2) Annotate every list in my POJO with #JsonAdapter(ListFirebaseDeserializer::class), for instance:
class MyCustomObject {
#JsonAdapter(ListFirebaseDeserializer::class)
var myPaymentList = ArrayList<Payment>()
}
It could be a pain if you already have lots of lists to annotate, but it is better than having to use maps instead.
Hope it helps!
http://localhost:8080/users?firstName=a&lastName=b ---> where firstName=a and lastName=b
How to make it to or ---> where firstName=a or lastName=b
But when I set QuerydslBinderCustomizer customize
#Override
default public void customize(QuerydslBindings bindings, QUser user) {
bindings.bind(String.class).all((StringPath path, Collection<? extends String> values) -> {
BooleanBuilder predicate = new BooleanBuilder();
values.forEach( value -> predicate.or(path.containsIgnoreCase(value) );
});
}
http://localhost:8080/users?firstName=a&firstName=b&lastName=b ---> where (firstName=a or firstName = b) and lastName=b
It seem different parameters with AND. Same parameters with what I set(predicate.or/predicate.and)
How to make it different parameters with AND like this ---> where firstName=a or firstName=b or lastName=b ??
thx.
Your current request param are grouped as List firstName and String lastName. I see that you want to keep your request parameters without a binding, but in this case it would make your life easier.
My suggestion is to make a new class with request param:
public class UserRequest {
private String lastName;
private List<String> firstName;
// getters and setters
}
For QueryDSL, you can create a builder object:
public class UserPredicateBuilder{
private List<BooleanExpression> expressions = new ArrayList<>();
public UserPredicateBuilder withFirstName(List<String> firstNameList){
QUser user = QUser.user;
expressions.add(user.firstName.in(firstNameList));
return this;
}
//.. same for other fields
public BooleanExpression build(){
if(expressions.isEmpty()){
return Expressions.asBoolean(true).isTrue();
}
BooleanExpression result = expressions.get(0);
for (int i = 1; i < expressions.size(); i++) {
result = result.and(expressions.get(i));
}
return result;
}
}
And after you can just use the builder as :
public List<User> getUsers(UserRequest userRequest){
BooleanExpression expression = new UserPredicateBuilder()
.withFirstName(userRequest.getFirstName())
// other fields
.build();
return userRepository.findAll(expression).getContent();
}
This is the recommended solution.
If you really want to keep the current params without a binding (they still need some kind of validation, otherwise it can throw an Exception in query dsl binding)
you can group them by path :
Map<StringPath,List<String>> values // example firstName => a,b
and after that to create your boolean expression based on the map:
//initial value
BooleanExpression result = Expressions.asBoolean(true).isTrue();
for (Map.Entry entry: values.entrySet()) {
result = result.and(entry.getKey().in(entry.getValues());
}
return userRepository.findAll(result);
console print:
io.netty.buffer.AdvancedLeakAwareByteBuf.readBytes(AdvancedLeakAwareByteBuf.java:496)
org.springframework.core.io.buffer.NettyDataBuffer.read(NettyDataBuffer.java:149)
org.springframework.core.io.buffer.NettyDataBuffer.read(NettyDataBuffer.java:38)
ipf.gwservice.filter.LoginFilter$1.lambda$writeWith$0(LoginFilter.java:61)
reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:107)
error line : dataBuffer.read(content);
How I fix it
ServerHttpResponse response = exchange.getResponse();
DataBufferFactory bufferFactory = response.bufferFactory();
ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(response) {
#Override
public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
if (body instanceof Flux) {
Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
return super.writeWith(fluxBody.map(dataBuffer -> {
byte[] content = new byte[dataBuffer.readableByteCount()];
dataBuffer.read(content);
ReferenceCountUtil.release(dataBuffer);
dataBuffer = null;
return bufferFactory.wrap("...........".getBytes(Charsets.UTF_8));
}));
}
return super.writeWith(body);
}
};
return chain.filter(exchange.mutate().response(decoratedResponse).build()); // replace response with decorator
There is an underlying problem while using Response Decorator involving reading byte buffer. I had this problem and after weeks of trying with various suggestion as options, managed to pin-point this problem using a sample application - https://github.com/nilavalagansugumaran/gateway-netty-memory-leak-issues. Spring-Gateway team referred me to an alternate approach ie ModifyResponseBodyGatewayFilter which looks resolved the issue. Actual issue reported to Spring-Gateway team https://github.com/spring-cloud/spring-cloud-gateway/issues/664. Hope this helps.