BE: Fix CORS once again (#3957)

(cherry picked from commit 9549f68)

Author: Haarolean

kafka-ui-api/src/main/java/com/provectus/kafka/ui/config/CorsGlobalConfiguration.java

@@ -1,18 +1,41 @@
 package com.provectus.kafka.ui.config;
 
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.web.reactive.config.CorsRegistry;
 import org.springframework.web.reactive.config.WebFluxConfigurer;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebFilter;
+import org.springframework.web.server.WebFilterChain;
+import reactor.core.publisher.Mono;
 
 @Configuration
-public class CorsGlobalConfiguration implements WebFluxConfigurer {
+public class CorsGlobalConfiguration {
 
-  @Override
-  public void addCorsMappings(CorsRegistry registry) {
-    registry.addMapping("/**")
-        .allowedOrigins("*")
-        .allowedMethods("*")
-        .allowedHeaders("*")
-        .allowCredentials(false);
+  @Bean
+  public WebFilter corsFilter() {
+    return (final ServerWebExchange ctx, final WebFilterChain chain) -> {
+      final ServerHttpRequest request = ctx.getRequest();
+
+      final ServerHttpResponse response = ctx.getResponse();
+      final HttpHeaders headers = response.getHeaders();
+      headers.add("Access-Control-Allow-Origin", "*");
+      headers.add("Access-Control-Allow-Methods", "GET, PUT, POST, DELETE, OPTIONS");
+      headers.add("Access-Control-Max-Age", "3600");
+      headers.add("Access-Control-Allow-Headers", "Content-Type");
+
+      if (request.getMethod() == HttpMethod.OPTIONS) {
+        response.setStatusCode(HttpStatus.OK);
+        return Mono.empty();
+      }
+
+      return chain.filter(ctx);
+    };
   }
+
 }