Reactive web client and exception handling for rest requests

Author: ardizioa

pom.xml

@@ -24,6 +24,7 @@
 <java.version>1.8</java.version>
 <spring-boot-admin.version>2.0.0</spring-boot-admin.version>
 <dse-driver.version>1.1.2</dse-driver.version>
+<reactor.kafka.version>1.0.0.RELEASE</reactor.kafka.version>
 </properties>
 
 <dependencies>
@@ -45,6 +46,11 @@
  <version>${dse-driver.version}</version>
 	</dependency>
 
+<dependency>
+ <groupId>io.projectreactor.kafka</groupId>
+ <artifactId>reactor-kafka</artifactId>
+ <version>${reactor.kafka.version}</version>
+</dependency>
 
 <dependency>
 <groupId>org.springframework.boot</groupId>

src/main/java/com/aardizio/client/RestClientErrorHandler.java

@@ -0,0 +1,24 @@
+package com.aardizio.client;
+
+
+import com.aardizio.errors.*;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.web.reactive.function.client.ClientResponse;
+
+import reactor.core.publisher.Mono;
+/**
+ * Generic error handler for rest requests.
+ * @author Alessandro Pio Ardizio
+ */
+public class RestClientErrorHandler {
+
+ private static final Logger log = LoggerFactory.getLogger(RestClientExample.class);
+
+ public static Mono<Throwable> handle(ClientResponse cr){
+ log.error(cr.toString());
+ // TODO do exception mapping here
+ return Mono.just(new RestClientException(cr.statusCode().toString() , "Message" ,cr.body(null)));
+ }
+
+}

src/main/java/com/aardizio/client/RestClientExample.java

@@ -0,0 +1,29 @@
+package com.aardizio.client;
+
+import com.aardizio.model.Hotels;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.web.reactive.function.client.WebClient;
+
+import reactor.core.publisher.Flux;
+
+/**
+ * Example web client to rest calls.
+ * @author Alessandro Pio Ardizio
+ * 
+ */
+public class RestClientExample {
+
+ public Flux<Hotels> send() {
+ WebClient client = WebClient.create("http://microservice");
+ Flux<Hotels> hotels = client.get()
+ .uri("/hotels")
+ .accept(MediaType.APPLICATION_JSON)
+ .retrieve()
+ .onStatus(HttpStatus::is4xxClientError, RestClientErrorHandler::handle)
+ .onStatus(HttpStatus::is5xxServerError, RestClientErrorHandler::handle)
+ .bodyToFlux(Hotels.class);
+ return hotels;
+ }
+
+}

src/main/java/com/aardizio/errors/RestClientException.java

@@ -0,0 +1,25 @@
+package com.aardizio.errors;
+
+import java.io.Serializable;
+
+public class RestClientException extends Exception implements Serializable{
+
+ private static final long serialVersionUID = 1L ;
+
+ private String code;
+ private String infos;
+
+ public RestClientException(String code ,String message , String infos){
+ super(message);
+ this.code = code;
+ this.infos = infos;
+ }
+
+ public String getCode(){
+ return this.code;
+ }
+
+ public String getInfos(){
+ return this.infos;
+ }
+}