Core: Extend secondary cache support with optional security header (#159)

Author: Net-burst

src/main/java/org/prebid/cache/handlers/cache/PostCacheHandler.java

@@ -27,6 +27,7 @@
 import org.prebid.cache.routers.ApiConfig;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.stereotype.Component;
@@ -44,6 +45,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 @Component
@@ -210,6 +212,7 @@ private void sendRequestToSecondaryPrebidCacheHosts(List<PayloadWrapper> payload
                     .uri(uriBuilder -> uriBuilder.path(config.getSecondaryCachePath())
                             .queryParam("secondaryCache", "yes").build())
                     .contentType(MediaType.APPLICATION_JSON)
+                    .headers(enrichWithSecurityHeader())
                     .bodyValue(RequestObject.of(payloadTransfers))
                     .exchange()
                     .transform(CircuitBreakerOperator.of(circuitBreaker))
@@ -228,6 +231,13 @@ private void sendRequestToSecondaryPrebidCacheHosts(List<PayloadWrapper> payload
         }
     }
 
+    private Consumer<HttpHeaders> enrichWithSecurityHeader() {
+        final String apiKey = apiConfig.getApiKey();
+        return apiKey != null
+                ? httpHeaders -> httpHeaders.set(API_KEY_HEADER, apiKey)
+                : httpHeaders -> { };
+    }
+
     private PayloadTransfer wrapperToTransfer(final PayloadWrapper wrapper) {
         return PayloadTransfer.builder().type(wrapper.getPayload().getType())
                 .key(wrapper.getId()).value(wrapper.getPayload().getValue()).expiry(wrapper.getExpiry()).build();