added apache proxy address strategy as a config option

src/main/java/ca/uhn/fhir/jpa/starter/AppProperties.java

@@ -66,6 +66,25 @@ public class AppProperties {
 
   private Boolean lastn_enabled = false;
 
+  private Boolean use_apache_address_strategy = false;
+  private Boolean use_apache_address_strategy_https = false;
+
+  public Boolean getUse_apache_address_strategy() {
+    return use_apache_address_strategy;
+  }
+
+  public void setUse_apache_address_strategy(Boolean use_apache_address_strategy) {
+    this.use_apache_address_strategy = use_apache_address_strategy;
+  }
+
+    public Boolean getUse_apache_address_strategy_https() {
+    return use_apache_address_strategy_https;
+  }
+
+  public void setUse_apache_address_strategy_https(Boolean use_apache_address_strategy_https) {
+    this.use_apache_address_strategy_https = use_apache_address_strategy_https;
+  }
+
   public Integer getDefer_indexing_for_codesystems_of_size() {
     return defer_indexing_for_codesystems_of_size;
   }

src/main/java/ca/uhn/fhir/jpa/starter/BaseJpaRestfulServer.java

@@ -25,6 +25,8 @@ import ca.uhn.fhir.narrative.INarrativeGenerator;
 import ca.uhn.fhir.narrative2.NullNarrativeGenerator;
 import ca.uhn.fhir.rest.server.ETagSupportEnum;
 import ca.uhn.fhir.rest.server.HardcodedServerAddressStrategy;
+import ca.uhn.fhir.rest.server.ApacheProxyAddressStrategy;
+import ca.uhn.fhir.rest.server.IncomingRequestAddressStrategy;
 import ca.uhn.fhir.rest.server.RestfulServer;
 import ca.uhn.fhir.rest.server.interceptor.*;
 import ca.uhn.fhir.rest.server.interceptor.partition.RequestTenantPartitionInterceptor;
@@ -232,6 +234,12 @@ public class BaseJpaRestfulServer extends RestfulServer {
     String serverAddress = appProperties.getServer_address();
     if (!Strings.isNullOrEmpty(serverAddress)) {
       setServerAddressStrategy(new HardcodedServerAddressStrategy(serverAddress));
+    } else if (appProperties.getUse_apache_address_strategy()) {
+      boolean useHttps = appProperties.getUse_apache_address_strategy_https();
+      setServerAddressStrategy(useHttps ? ApacheProxyAddressStrategy.forHttps() :
+                    ApacheProxyAddressStrategy.forHttp());
+    } else {
+      setServerAddressStrategy(new IncomingRequestAddressStrategy());
     }
 
     /*

src/main/resources/application.yaml

@@ -28,6 +28,10 @@ spring:
 
 hapi:
   fhir:
+    ### enable to use the ApacheProxyAddressStrategy which uses X-Forwarded-* headers
+    ### to determine the FHIR server address
+#   use_apache_address_strategy: false
+#   use_apache_address_strategy_https: false
     ### enable to set the Server URL
 #    server_address: http://hapi.fhir.org/baseR4
     ### This is the FHIR version. Choose between, DSTU2, DSTU3, R4 or R5