I am working heavily with a webflux based spring boot application.
the problem I am facing, is that there is one service I have to call to, which is a traditional spring boot app, and is not reactive!
Here is an example endpoint which is close to the idea of said legacy system :
#RequestMapping(value = "/people/**", method = RequestMethod.GET)
public ResponseEntity<InputStreamResource> getPerson(HttpServletRequest request) {
String pattern = (String) request.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
String key = new AntPathMatcher().extractPathWithinPattern(pattern, request.getRequestURI());
return personService.getPersonByKey(key);
}
I KNOW I can't achieve true reactive goodness with this, is there a happy medium of non blocking and blocking I can achieve here?
Thanks
When you use WebClient to call the service from your Spring WebFlux application, then it will work in Reactive non blocking way. Meaning you can achieve true reactive goodness on your application. The thread will not be blocked until the upstream service returns the response.
Below is an example code for calling a service using WebClient:
WebClient webClient = WebClient.create("http://localhost:8080");
Mono<Person> result = webClient.get()
.uri("/people/{id}")
.retrieve()
.bodyToMono(Person.class);
Related
I'm using spring boot and I want to assert an asynchronous side effect by calling a secured endpoint with MockMvc.
I have been using Awaitility, but apparently the mocked security context is lost when executing in a different thread.
I couldn't find a way of passing the context, I tried with SecurityContextHolder.setContext() but it didn't work, I guess spring's MockMvc stores the context in a different way.
#Test
#WithMockUser(authorities = "admin", username = "user")
void shouldRunSideEffectAsync() throws Exception {
mockMvc.perform(post("/foo")).andExpect(status().isAccepted());
await()
.atMost(TIMEOUT)
.untilAsserted(() -> mockMvc.perform(get("/foo")).andExpect(status().isOk()));
}
The GET would return 404 for a while and then 200 when the async task is completed. However this will always return 403 as the MockUser info is lost.
How can I solve this?
You almost got it. Security for MockMvc is implemented by TestSecurityContextHolderPostProcessor, which uses the TestSecurityContextHolder to set/get the security context. That is just a wrapper around the SecurityContextHolder.
So you can use TestSecurityContextHolder.setContext() in the awaitility thread and it should work.
I have two Java processes - which get spawned from the same Jar using different run configurations
Process A - Client UI component , Developed Using Spring bean xml based approach. No Spring Boot is there.
Process B - A new Springboot Based component , hosts REST End points.
Now from Process A , on various button click how can I call the REST end points on Process B using Feign Client.
Note - Since Process A is Spring XML based , right at the moment we can not convert that to Spring boot. Hence #EnableFeignClients can not be used to initialise the Feign Clients
So Two questions
1) If the above is possible how to do it ?
2) Till Process A is moved to Spring boot - is Feign still an easier option than spring REST template ?
Feign is a Java to HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSockets and you can easily use feign without spring boot. And Yes, feign still better option to use because Feign Simplify the HTTP API Clients using declarative way as Spring REST does.
1) Define http methods and endpoints in interface.
#Headers({"Content-Type: application/json"})
public interface NotificationClient {
#RequestLine("POST")
String notify(URI uri, #HeaderMap Map<String, Object> headers, NotificationBody body);
}
2) Create Feign client using Feign.builder() method.
Feign.builder()
.encoder(new JacksonEncoder())
.decoder(customDecoder())
.target(Target.EmptyTarget.create(NotificationClient.class));
There are various decoders available in feign to simplify your tasks.
You are able to just initialise Feign in any code (without spring) just like in the readme example:
public static void main(String... args) {
GitHub github = Feign.builder()
.decoder(new GsonDecoder())
.target(GitHub.class, "https://api.github.com");
...
}
Please take a look at the getting started guide: feign on github
I am using Spring WebFlux and WebClient for my web application.
My application potentially can call a 'N' number of other micro services which is also hosted by us.
Now the problem is that i want to restrict my WebClient to invoke a limited number of simultaneous calls to the existing micro services.
Also, I don't want to do it at individual call level, but at application level.
I have already gone through "How to limit the number of active Spring WebClient calls?" and "How to limit the request/second with WebClient?", to no avail.
You can create a WebClient instance like this:
ConnectionProvider fixedPool = ConnectionProvider.fixed("fixedPool", maxConnections, acquireTimeout);
HttpClient httpClient = HttpClient.create(fixedPool);
WebClient webClient = WebClient.builder()
.clientConnector(new ReactorClientHttpConnector(httpClient)).build();
Since reactor-netty 0.9.5, the method described by Brian Clozel is now deprecated, use instead:
ConnectionProvider fixedPool = ConnectionProvider.builder("fixedPool")
.maxConnections(200)
.pendingAcquireTimeout(Duration.ofMinutes(3))
.build();
HttpClient httpClient = HttpClient.create(fixedPool);
WebClient webClient = WebClient.builder()
.clientConnector(new ReactorClientHttpConnector(httpClient))
.build();
max connectiond and pending acquire timeout are random values, change them according to your needs.
I'm new to Jhipster, and wondering if it's possible to manually call a microservices from the gateway code using a RestTemplate or something else.
My first idea was to call the gateway itself... but I'm not sure it's a good idea.
My second idea was to try and call the service by it's URL. My concern is that I don't want to hardcode the port of a given node. Instead, i want to use proper loadbalancing.
I've read this article https://dzone.com/articles/spring-cloud-rest-client-with-netflix-ribbon-basic, but the injection failed.
I've read somewhere else that you now need to manually add the bean declaration
#LoadBalanced
#Bean
RestTemplate restTemplate(){
return new RestTemplate();
}
But now I'm struggling with the actual URI : what I am supposed to put as the root? (xxxxx)
final HcpVersionedhcp hcpVersionedhcp =
restTemplate.exchange("http://xxxxx/api/user-data/byLogin/", UserData.class);
The only configuration I have in my gateway application.yml is
ribbon:
eureka:
enabled: true
The "xxxxx" has to be replaced with your services name. If your service is "foo", you should write http://foo/api/user....
If you are using JWT as authentication, you need to auth using a user a in JHipster, or to pass the JWT token from request when possible. However the is no best practice for JWT auth, so I would suggest to go the JHipster UAA way.
In a few words, you have one more service responsible for authentication and authorization. To access your service from another service, you can use #AuthorizedFeignClient on interfaces, similar to JPA.
So you define:
#AuthorizedFeignClient(name = "xxxx")
interface XxxClient {
#RequestMapping(value = "/api/some-entities/{id}")
SomeEntity getSomeEntityById(Long #Path("id") id);
}
And inject it in any spring service / rest-controller like this:
#Inject
private XxxClient xxxClient;
//...
public void someAction() {
//...
xxxClient.getEntityById(id);
//..
}
Which internally implement client authorization flows ...
I have developed few RESTful methods and exposed them via Apache Cxf
I'm developing the client side application using Spring MVC and I'm looking for a simple example to demonstrate how to call/consume these REST methods using Spring MVC
I know how to do it using Apache http client but prefer to use Spring MVC in case such this has already been implemented there.
Spring provides simple wrapper to consume RESTful services called RestTemplate. It performs path variable resolution, marshalling and unmarshalling:
Map<String, Integer> vars = new HashMap<String, Integer>();
vars.put("hotelId", 42);
vars.put("roomId", 13);
Room room = restTemplate.getForObject(
"http://example.com/hotels/{hotelId}/rooms/{roomId}",
Room.class, vars);
Assuming Room is a JAXB object which can be understood by The RestTemplate.
Note that this class has nothing to do with Spring MVC. You can use it in MVC application, but also in a standalone app. It is a client library.
See also
REST in Spring 3: RestTemplate
Use path variables to consume REST data. For example:
https://localhost/products/{12345}
This pattern should give you the detail of the product having product id 12345.
#RequestMapping(value="/products/{productId}")
#ResponseBody
public SomeModel doProductProcessing(#PathVariable("productId") String productId){
//do prpcessing with productid
return someModel;
}
If you want to consume Rest Service from another service then have a look at:
http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/web/client/RestTemplate.html
and
http://www.informit.com/guides/content.aspx?g=java&seqNum=546