I have this singleton class which will start when the application starts and the method invokes itself for every 30 seconds.
#Singleton
#Startup
public class myClass{
#Schedule(second="*/30", minute="*", hour="*")
public void serviceRequest(){
String url = "";
//send request
}
}
the url will be something like http://localhost:7001/webapp/rest/tasks/mytask. I don't want to hardcode the url. Instead, I want to somehow get that from the system (or somewhere). I've tried injecting resource like HttpServletRequest but that didn't work.
Thanks in advance.
In case you're using JAX-RS, then this will work:
#RequestScoped #Path("tasks")
public class TaskResource {
#GET #Path("{id}")
public Response getTask(#PathParam("id") String id) {
/* whatever */
}
}
URI uri = UriBuilder.fromResource(TaskResource.class)
.segment("{id}").build("mytask");
The url will be provided by an external service so I dont need to worry about host and port number since ill get full url to that rest service. Because the service isn't available so I made an in house rest service to test my functionality. I guess I will harcode the url for now.
Related
Trying to figure out if I can use Spring Reactive (Flux/Mono) with Spring MVC ?
The structure of microservices using Spring MVC + Feign Client, Eureka Server (Netflix OSS), Hystrix, MySQL database.
My first microservice addDistanceClient adds data to the database.
Here is an example controller:
#RequestMapping("/")
#RestController
public class RemoteMvcController {
#Autowired
EmployeeService service;
#GetMapping(path = "/show")
public List<EmployeeEntity> getAllEmployeesList() {
return service.getAllEmployees();
}
}
Here I can use Mono/Flux, I think there will be no problems.
My second microservice is showDistanceClient - it is not directly connected to the database.
He has a method that calls the method (as described above) on the first microservice to retrieve data from the database.
It uses the Feign Client.
Second microservice controller:
#Controller
#RequestMapping("/")
public class EmployeeMvcController {
private ServiceFeignClient serviceFeignClient;
#RequestMapping(path = "/getAllDataFromAddService")
public String getData2(Model model) {
List<EmployeeEntity> list = ServiceFeignClient.FeignHolder.create().getAllEmployeesList();
model.addAttribute("employees", list);
return "resultlist-employees";
}
}
and ServiceFeignClient itself, with which we call the method on the first microservice, looks like this:
#FeignClient(name = "add-client", url = "http://localhost:8081/", fallback = Fallback.class)
public interface ServiceFeignClient {
class FeignHolder {
public static ServiceFeignClient create() {
return HystrixFeign.builder().encoder(new GsonEncoder()).decoder(new GsonDecoder()).target(ServiceFeignClient.class, "http://localhost:8081/", new FallbackFactory<ServiceFeignClient>() {
#Override
public ServiceFeignClient create(Throwable throwable) {
return new ServiceFeignClient() {
#Override
public List<EmployeeEntity> getAllEmployeesList() {
System.out.println(throwable.getMessage());
return null;
}
};
}
});
}
}
#RequestLine("GET /show")
List<EmployeeEntity> getAllEmployeesList();
}
It is working properly now. Those, if both microservices are OK, I get data from the database.
If the first microservice (addDistanceClient) is dead, then when I call the method on second microservice (showDistanceClient) to get data from the database through the first microservice (using Feign Client on second microservice), I get a page on which the spinner is spinning and the text that the service is unavailable, try again later. All perfectly.
My goal:
To do this using Spring Reactive (not sure if this will help me, but I think I'm thinking in the right direction) to make the message that the service is currently unavailable and the spinning spinner on the second microservice will automatically disappear and the data from the database will be displayed as soon as the first microservice (addDistanceClient) will come to life again (without re-sending the request, i.e. without reloading the page).
Will I be able to do this through Spring WebFlux ?
I know that a stream is used through Spring WebFlux, which itself will notify us if data appears in it, we do not need to resubmit the request here.
I started thinking about this and cannot figure out how to do this:
1) using Spring Reactive
In this case, I need to implement Flux/Mono into the MVC model in the second showDistanceClient microservice, which returns HTML. I don't understand how. I know how to do this with REST.
2) If the first item is incorrect, maybe I need to use a WebSocket for this ?
If so, please share useful links with examples. I will be very grateful.
Indeed, this topic is very interesting to me and I want to understand it.
I will be very grateful for your help. Thanks everyone!
UPDATED POST:
I updated both controllers with REST + WebFlux. Everything works for me.
The first addDistanceClient service and its controller:
#RestController
#RequestMapping("/")
public class BucketController {
#Autowired
private BucketRepository bucketRepository;
// Get all Bucket from the database (every 1 second you will receive 1 record from the DB)
#GetMapping(value = "/stream/buckets/delay", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<Bucket> streamAllBucketsDelay() {
return bucketRepository.findAll().delayElements(Duration.ofSeconds(5));
}
}
He pulls out all the records from the database with an interval of 5 seconds each record. I added an interval for an example to test.
The second service is showDistanceClient and its controller.
Here I used WebClient instead of Feign Client.
#RestController
#RequestMapping("/")
public class UserController {
#Autowired
private WebClient webClient;
#Autowired
private WebClientService webClientService;
// Using WebClient
#GetMapping(value = "/getDataByWebClient",produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<Bucket> getDataByWebClient() {
return webClientService.getDataByWebClient();
}
}
and its Service layer (WebClientService):
#Service
public class WebClientService {
private static final String API_MIME_TYPE = "application/json";
private static final String API_BASE_URL = "http://localhost:8081";
private static final String USER_AGENT = "User Service";
private static final Logger logger = LoggerFactory.getLogger(WebClientService.class);
private WebClient webClient;
public WebClientService() {
this.webClient = WebClient.builder()
.baseUrl(API_BASE_URL)
.defaultHeader(HttpHeaders.CONTENT_TYPE, API_MIME_TYPE)
.defaultHeader(HttpHeaders.USER_AGENT, USER_AGENT)
.build();
}
public Flux<Bucket> getDataByWebClient() {
return webClient.get()
.uri("/stream/buckets/delay")
.exchange()
.flatMapMany(clientResponse -> clientResponse.bodyToFlux(Bucket.class));
}
}
Now everything works in a reactive environment. Fine.
But my problem remained unresolved.
My goal: everything works, everything is fine, and if I suddenly called on the second service a method that using WebClient called the first service to get the data, and at that moment my first service died, I received a message that the service is temporarily unavailable and then my first service My request for data was revived and I received all the data and instead of reporting that the service was temporarily unavailable I would get all the data (important: without reloading the page).
How do I achieve this ?
The context
I am currently working on an educational project. This implies two Spring Boot REST servers. One is an actual server, which does some processing.
The one I'm interested in is the other. It is a proxy which will redirect all calls to the first one. So that when I call http://localhost:8080/foo, my proxy server will in turn call http://localhost:8090/foo. And if the first server returns A, the proxy will return {"proxied": A, "someInformationAboutThisCall": B}.
I managed to get to this point with some probably inelegant but functioning code of which I give an excerpt below. The key here is that I use #RequestMapping("**") to achieve this. The next step is to design an interface that will make my additional information immediately legible, which is basically the point of this project. If I remove all #RequestMapping("**"), it works just fine.
The question
Now my problem is the following: having used #RequestMapping("**"), I cannot serve static content (the calls get redirect to the other REST server, which does not serve static content). How could I configure Spring Boot/Spring MVC to ignore resources available as static content when mapping the requests, or make the PathResourceResolver prioritary over my controller?` Or should I serve my static content from yet another JVM/server?
Thanks in advance for your help!
Edit of interest: while doing some tests, I discovered that the static content is served, with some restrictions, if I use #RequestMapping("*").
/index.html generates an error page (as does more generally any static content directly in public)
/itf/index.html works (as does more generally any file in public/itf or any other subdirectory of public)
/itf does not work: Spring Boot seems unaware of an index file in it. I must specify a full URI, down to the specific file I want to display.
This however does not work at all with #RequestMapping("**"), which I need.
The tentatives
I tried using a WebMvcConfigurerAdapter with an HandlerInterceptorAdapter (found on SO, SO again and many other places on the Internet), but could not start my project anymore because Spring boot then does not find the InterceptorRegistry bean (has there been recent changes in Spring Boot? I'm using the version 1.5.3.RELEASE).
I also tried some anti-matching but not only does it not work, it also feels very very dirty (and this whole project is probably not optimal, so that's saying a lot).
The code samples for the curious
My "proxy" controller
Note: you can suggest better ways to realize this in comments. Please keep in mind that, though I'm always open to enhancement suggestions, this was not my question.
#RestController
public class ProxyController {
#Value("${monitored.url.base}") // "http://localhost:8090"
private String redirectBase;
#RequestMapping(value = "**", method = {RequestMethod.POST, RequestMethod.PUT})
public ProxiedResponse proxifyRequestsWithBody(HttpServletRequest request, #RequestHeader HttpHeaders headers, #RequestBody Object body) throws URISyntaxException {
return proxifyRequest(request, headers, body);
}
#RequestMapping(value = "**")
public ProxiedResponse proxifyRequestsWithoutBody(HttpServletRequest request, #RequestHeader HttpHeaders headers) throws URISyntaxException {
return proxifyRequest(request, headers, null);
}
private ProxiedResponse proxifyRequest(HttpServletRequest request, #RequestHeader HttpHeaders headers, #RequestBody Object body) throws URISyntaxException {
final RequestEntity<Object> requestEntity = convertToRequestEntity(request, headers, body);
// call remote service
final ResponseEntity<Object> proxied = restTemplate.exchange(requestEntity, Object.class);
// Return service result + monitoring information
final ProxiedResponse response = new ProxiedResponse();
response.setProxied(proxied.getBody());
// set additional information
return response;
}
// Won't work properly for POST yet
private <T> RequestEntity<T> convertToRequestEntity(HttpServletRequest request, HttpHeaders headers, T body) throws URISyntaxException {
// Build proxied URL
final StringBuilder redirectUrl = new StringBuilder(redirectBase).append(request.getRequestURI());
final String queryString = request.getQueryString();
if (queryString != null) {
redirectUrl.append("?").append(queryString);
}
// TODO enhancement: transmit headers and request body to make this a real proxy
final HttpMethod httpMethod = HttpMethod.valueOf(request.getMethod());
return new RequestEntity<>(body, headers, httpMethod, new URI(redirectUrl.toString()));
}
}
My dirty attempt at excluding static resources URLs
#Configuration // adding #EnableWebMvc did not solve the problem
public class WebMvcConfiguration extends WebMvcConfigurerAdapter {
private static class StaticResourcesHandlerInterceptor extends HandlerInterceptorAdapter {
#Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
final String requestURI = request.getRequestURI();
if (requestURI == null || "/".equals(requestURI) || "/index.html".equals(requestURI) || requestURI.startsWith("/assets")) {
return super.preHandle(request, response, null);
}
return super.preHandle(request, response, handler);
}
}
#Autowired
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new StaticResourcesHandlerInterceptor()).addPathPatterns("/**");
}
}
You can split the path into a wild-card, and a named path variable which must match a negative lookahead regular expression.
#RequestMapping("/{variable:(?!static).*}/**")
You can then use #PathVariable String variable as an argument of your controller method to obtain the value of variable if you need to pass it.
(Would rather have written a comment but I have insufficient reputation)
Try to add the #EnableWebMvc annotation to your configuration:
#Configuration
#EnableWebMvc
public class WebMvcConfiguration extends WebMvcConfigurerAdapter {
...
}
I need this method to return an integer value:
[Route("api/[controller]")]
public class ValuesController : Controller
{
[HttpPost("ByPayment")]
public int Payment(string accountId, string mount, string shenase)
{
return 21;
}
}
When I go to the following address:
http://localhost:1070/api/values/Payment/ByPayment?accountId=258965&mount=85694&shenase=85456
I get the following error:
What's the problem? And how can I solve it?
I thing you wanted to send Get request with query string parameters.
1. Change the 'HttpPost' to 'HttpGet'
[HttpPost("ByPayment")] to [HttpGet("ByPayment")]
2. Also change your request url, Its not correct.
http://localhost:1070/api/values/Payment/ByPayment?accountId=258965&mount=85694&shenase=85456
to
http://localhost:1070/api/Values/ByPayment?accountId=258965&mount=85694&shenase=85456
Updated code
[Route("api/[controller]")]
public class ValuesController : Controller
{
[HttpGet("ByPayment")]
public int Payment(string accountId, string mount, string shenase)
{
return 21;
}
}
I suggest please read this tutorial to understand the basic of webapi.
There could be more reasons why you get the 404. But there is one thing that's definitely wrong - you are sending GET requests to a method that's marked with [HttpPost("ByPayment")] (which means it only responds to POST requests.
I don't know what you intended to do but you either have to change it to [HttpGet("ByPayment")] or use a REST client that can make POST requests (e.g. REST Easy.
Other reason could be that your controller has a wrong name. It should be called PaymentController.
I have a basic SpringBoot app. using Spring Initializer, embedded Tomcat, Thymeleaf template engine, and package as an executable JAR file.
I have this controller:
#Controller
#RequestMapping("/deviceevent")
public class DeviceEventController {
#RequestMapping(value={ "/list"}, method = { RequestMethod.GET})
public String deviceeventList() {
return "tdk/deviceEvent/DeviceEventList";
}
}
and this other test class. Tests using Spring's MockMVC framework. This drives an MVC application in a test, as if it was running in a container,
#RunWith(SpringJUnit4ClassRunner.class)
#WebAppConfiguration
#WebMvcTest
public class MockMvcTests {
// Pull in the application context created by #ContextConfiguration
#Autowired
private WebApplicationContext wac;
private MockMvc mockMvc;
#Before
public void setup() {
// Setup MockMVC to use our Spring Configuration
this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build();
}
#Test
public void getDeviceEventsTest() throws Exception {
this.mockMvc
.perform(get("/deviceevent/list") //
.accept(MediaType.parseMediaType("text/html;charset=UTF-8")))
.andExpect(status().isOk()) //
.andExpect(model().size(1)) //
.andExpect(forwardedUrl("tdk/deviceEvent/DeviceEventList"));
}
But I got this error in the forwarded URL. I always used this method in JSP, never in Thymeleaf, but I guess that It is the same:
java.lang.AssertionError: Forwarded URL expected:</tdk/deviceEvent/DeviceEventList> but was:<null>
Assuming a standard Thymeleaf/Spring setup, it looks like there is a misunderstanding with what the controller is doing - when the controller returns that string "tdk/deviceEvent/DeviceEventList" it is not forwarding the HTTP request somewhere, but returning a view name.
With a normal Spring-thymeleaf setup, that string corresponds to the name of a thymeleaf view that will be rendered on hitting that endpoint (I assume the controller is just serving a normal webpage - so that path probably corresponds to some file path most likely in src/main/resources - but again, this depends a lot on your spring config) - at this point the HTTP request has not been returned to the user, and Spring is still processing it - and will attempt to render the HTML view before returning to the user.
The forwarded URL is used if Spring is not rendering anything but instead returning a HTTP response to the user to forward them to another URL (which will start a different Spring request-response process) using a 301/302 mechanism.
Note the difference in the following methods:
#RequestMapping( value="/document", method=RequestMethod.GET )
public String newDocumentSettings( Model model ){
model.addAllAttributes( contentManagementService.documentToJson() );
return "pages/document-settings";
}
#RequestMapping( value="/document", method=RequestMethod.POST )
public String createNewDocument( #RequestParam String title, #RequestParam String overview, #RequestParam String tags ){
Document doc = documentService.createDocument( title, overview, tags );
return "redirect:/document/${doc.url}/1?getting-started";
}
The first renders the template at the given filepath, the second returns a redirect command to the browser to make another HTTP request to the given URL.
In any case, the forwardedUrl in your test case is because hte HTTP Response doesn't have a URL to forward to (because its returning the HTML). If you do want forwarding behaviour (e.g. you actually want to complete the response and the browser to make a second HTTP request) then you would likely need to update the controller as per example, however, if you are happy with the rendered html page, then the test is invalid (look at the Thymeleaf testing framework to see how to test templating).
Caveat: This is based on the assumption of default Spring-Boot config - if you have other config whereby that string does result in a forwarded HTTP request then this doesnt apply!
Taking a guess here, but the URL tdk/deviceEvent/DeviceEventList is probably not defined. Try replacing it with the URL associated with your context (edit as necessary):
#Test
public void getDeviceEventsTest() throws Exception {
this.mockMvc
.perform(get("/deviceevent/list")
.accept(MediaType.parseMediaType("text/html;charset=UTF-8")))
.andExpect(status().isOk())
.andExpect(model().size(1))
.andExpect(forwardedUrl("/WEB-INF/tdk/deviceEvent/DeviceEventList.html"));
}
Aside, instead of:
#RequestMapping(value={ "/list"}, method = { RequestMethod.GET})
you can use the shorthand:
#GetMapping("/list")
I am building a Spring Cloud project (Brixton.M4 with Spring Boot 1.3.1) with Eureka, Zuul and FeignClient where I am trying to add multi tenancy support (Tenants are identified by subdomain : tenant1.myservice.com). To do so, I would like to somehow pass the original subdomain along requests that are forwarded from a service to the other via Feign but I can't seem to be able to find the right way to do it.
What I have is a client that exposes a #RestController which calls a #FeignClient to communicate with my backend which exposes server operations to the client through its own #RestController.
The #FeignClient using same interface as my #RestController on the server :
#FeignClient(name = "product")
public interface ProductService extends IProductService {
}
What I am currently trying to do is set a header in a RequestInterceptor :
#Component
public class MultiTenancyRequestInterceptor implements RequestInterceptor {
private CurrentTenantProvider currentTenantProvider;
#Autowired
public MultiTenancyRequestInterceptor(CurrentTenantProvider currentTenantProvider) {
this.currentTenantProvider = currentTenantProvider;
}
#Override
public void apply(RequestTemplate template) {
try {
template.header("TENANT", currentTenantProvider.getTenant());
} catch (Exception e) {
// "oops"
}
}
}
My provider class is a simple component where I'm trying to inject a request / session scope bean :
#Component
public class CurrentTenantProvider {
#Autowired
private CurrentTenant currentTenant;
//...
}
The bean (I tried both session and request scope) :
#Bean
#Scope(value = WebApplicationContext.SCOPE_SESSION, proxyMode = ScopedProxyMode.TARGET_CLASS)
public CurrentTenant currentTenant() {
return new CurrentTenant();
}
On the server, I use Hibernate multitenant provider that is supposed to catch the header value and use it to define which DB to connect to :
#Autowired
private HttpServletRequest httpRequest;
#Override
public String resolveCurrentTenantIdentifier() {
return httpRequest.getHeader("TENANT");
}
It seems the Feign call to the server is done in another thread and out of the incoming request scope, so i'm not sure how to pass that value along.
It all works fine when I hardcode the tenant value in the RequestInterceptor so I know the rest is working properly.
I have also looked at many other posts about Zuul "X-Forwaded-For" header and cannot find it in the request received on the server. I have also tried adding a ZuulFilter to pass host name to next request but what I see is that original request to the Client is picked up by the ZuulFilter and I can add but not when the Feign request is sent to the backend service even if I map it in zuul (i guess that is intended ?).
I am not really sure what's the next step and would appreciate some suggestions.
Hope that it's of any use for you but we're doing sth similar in Spring-Cloud-Sleuth but we're using a ThreadLocal to pass span between different libraries and approaches (including Feign + Hystrix).
Here is an example with the highlighted line where we retrieve the Span from the thread local: https://github.com/spring-cloud/spring-cloud-sleuth/blob/master/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/TraceFeignClientAutoConfiguration.java#L123