#458: Possibility to set outgoing HTTP headers in FHIR consumers

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/AbstractBundleProvider.java

@@ -18,6 +18,7 @@
 
 import ca.uhn.fhir.model.primitive.InstantDt;
 import ca.uhn.fhir.rest.api.server.IBundleProvider;
+import jakarta.servlet.http.HttpServletResponse;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 
 import java.util.HashMap;
@@ -35,16 +36,18 @@ public abstract class AbstractBundleProvider implements IBundleProvider {
     private final Object payload;
     private final Map<String, Object> headers;
     private final boolean sort;
+    protected final HttpServletResponse httpServletResponse;
 
-    public AbstractBundleProvider(RequestConsumer consumer, Object payload, Map<String, Object> headers) {
-        this(consumer, false, payload, headers);
+    public AbstractBundleProvider(RequestConsumer consumer, Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse) {
+        this(consumer, false, payload, headers, httpServletResponse);
     }
 
-    public AbstractBundleProvider(RequestConsumer consumer, boolean sort, Object payload, Map<String, Object> headers) {
+    public AbstractBundleProvider(RequestConsumer consumer, boolean sort, Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse) {
         this.consumer = consumer;
         this.payload = payload;
         this.headers = headers;
         this.sort = sort;
+        this.httpServletResponse = httpServletResponse;
     }
 
     @Override
@@ -57,8 +60,11 @@ public Integer preferredPageSize() {
         return null;
     }
 
-    protected List<IBaseResource> obtainResources(Object payload, Map<String, Object> parameters) {
-        return consumer.handleBundleRequest(payload, parameters);
+    protected List<IBaseResource> obtainResources(Object payload, Map<String, Object> inHeaders) {
+        HashMap<String, Object> outHeaders = new HashMap<>();
+        List<IBaseResource> resources = consumer.handleBundleRequest(payload, inHeaders, outHeaders);
+        FhirProvider.processOutHeaders(outHeaders, httpServletResponse);
+        return resources;
     }
 
     protected RequestConsumer getConsumer() {

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/AbstractPlainProvider.java

@@ -26,6 +26,8 @@
 
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
+
+import java.util.HashMap;
 import java.util.List;
 import java.util.Optional;
 
@@ -91,8 +93,11 @@ protected final <R extends IBaseResource> R requestResource(
             RequestDetails requestDetails) {
         var consumer = getRequestConsumer(requestDetails).orElseThrow(() ->
                 new IllegalStateException("Consumer is not initialized"));
-        var headers = enrichParameters(parameters, httpServletRequest, requestDetails);
-        return consumer.handleResourceRequest(payload, headers, resultType);
+        var inHeaders = enrichParameters(parameters, httpServletRequest, requestDetails);
+        var outHeaders = new HashMap<String, Object>();
+        R resource = consumer.handleResourceRequest(payload, inHeaders, outHeaders, resultType);
+        processOutHeaders(outHeaders, httpServletResponse);
+        return resource;
     }
 
     /**
@@ -114,17 +119,20 @@ protected final <R extends IBaseResource> List<R> requestBundle(
             RequestDetails requestDetails) {
         var consumer = getRequestConsumer(requestDetails).orElseThrow(() ->
                 new IllegalStateException("Consumer is not initialized"));
-        var headers = enrichParameters(parameters, httpServletRequest, requestDetails);
+        var inHeaders = enrichParameters(parameters, httpServletRequest, requestDetails);
         if (resourceType != null) {
-            headers.put(Constants.FHIR_RESOURCE_TYPE_HEADER, resourceType);
+            inHeaders.put(Constants.FHIR_RESOURCE_TYPE_HEADER, resourceType);
         }
-        return consumer.handleBundleRequest(payload, headers);
+        var outHeaders = new HashMap<String, Object>();
+        List<R> resources = consumer.handleBundleRequest(payload, inHeaders, outHeaders);
+        processOutHeaders(outHeaders, httpServletResponse);
+        return resources;
     }
 
     /**
      * Requests a {@link IBundleProvider} that takes over the responsibility to fetch requested
      * bundles. The type of the returned {@link IBundleProvider} instance is determined
-     * by the {@link #consumer RequestConsumer} impelmentation.
+     * by the {@link #consumer RequestConsumer} implementation.
      *
      * @param payload             FHIR request resource (often null)
      * @param searchParameters    FHIR search parameters
@@ -142,11 +150,12 @@ protected final IBundleProvider requestBundleProvider(
             RequestDetails requestDetails) {
         var consumer = getRequestConsumer(requestDetails).orElseThrow(() ->
                 new IllegalStateException("Consumer is not initialized"));
-        var headers = enrichParameters(searchParameters, httpServletRequest, requestDetails);
+        var inHeaders = enrichParameters(searchParameters, httpServletRequest, requestDetails);
         if (resourceType != null) {
-            headers.put(Constants.FHIR_RESOURCE_TYPE_HEADER, resourceType);
+            inHeaders.put(Constants.FHIR_RESOURCE_TYPE_HEADER, resourceType);
         }
-        return consumer.handleBundleProviderRequest(payload, headers);
+        IBundleProvider bundleProvider = consumer.handleBundleProviderRequest(payload, inHeaders, httpServletResponse);
+        return bundleProvider;
     }
 
     /**
@@ -166,8 +175,11 @@ protected final MethodOutcome requestAction(
             RequestDetails requestDetails) {
         var consumer = getRequestConsumer(requestDetails).orElseThrow(() ->
                 new IllegalStateException("Consumer is not initialized"));
-        var headers = enrichParameters(parameters, httpServletRequest, requestDetails);
-        return consumer.handleAction(payload, headers);
+        var inHeaders = enrichParameters(parameters, httpServletRequest, requestDetails);
+        var outHeaders = new HashMap<String, Object>();
+        MethodOutcome outcome = consumer.handleAction(payload, inHeaders, outHeaders);
+        processOutHeaders(outHeaders, httpServletResponse);
+        return outcome;
     }
 
 

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/EagerBundleProvider.java

@@ -16,6 +16,7 @@
 
 package org.openehealth.ipf.commons.ihe.fhir;
 
+import jakarta.servlet.http.HttpServletResponse;
 import lombok.NonNull;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 
@@ -33,12 +34,12 @@ public class EagerBundleProvider extends AbstractBundleProvider {
 
     private transient List<IBaseResource> resources;
 
-    public EagerBundleProvider(RequestConsumer consumer, Object payload, Map<String, Object> headers) {
-        this(consumer, false, payload, headers);
+    public EagerBundleProvider(RequestConsumer consumer, Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse) {
+        this(consumer, false, payload, headers, httpServletResponse);
     }
 
-    public EagerBundleProvider(RequestConsumer consumer, boolean sort, Object payload, Map<String, Object> headers) {
-        super(consumer, sort, payload, headers);
+    public EagerBundleProvider(RequestConsumer consumer, boolean sort, Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse) {
+        super(consumer, sort, payload, headers, httpServletResponse);
     }
 
     @Override

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/FhirProvider.java

@@ -20,6 +20,8 @@
 import ca.uhn.fhir.rest.api.server.RequestDetails;
 
 import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
 import java.io.Serializable;
 import java.util.*;
 
@@ -140,4 +142,17 @@ private static Map<String, List<String>> extractHttpHeaders(HttpServletRequest h
         }
         return result;
     }
+
+    public static void processOutHeaders(Map<String, Object> outHeaders, HttpServletResponse httpServletResponse) {
+        var httpHeadersObject = outHeaders.get(Constants.HTTP_OUTGOING_HEADERS);
+        if (httpHeadersObject instanceof Map) {
+            var headers = (Map<String, List<String>>) httpHeadersObject;
+            for (var entry : headers.entrySet()) {
+                for (var value : entry.getValue()) {
+                    httpServletResponse.addHeader(entry.getKey(), value);
+                }
+            }
+        }
+    }
+
 }

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/LazyBundleProvider.java

@@ -20,6 +20,7 @@
 import com.google.common.collect.Range;
 import com.google.common.collect.RangeSet;
 import com.google.common.collect.TreeRangeSet;
+import jakarta.servlet.http.HttpServletResponse;
 import lombok.NonNull;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 import org.slf4j.Logger;
@@ -65,9 +66,10 @@ public class LazyBundleProvider extends AbstractBundleProvider {
      * @param cacheResults cache results. So far, only the result set size is cached
      * @param payload      incoming payload
      * @param headers      incoming headers
+     * @param httpServletResponse HTTP servlet response
      */
-    public LazyBundleProvider(RequestConsumer consumer, boolean cacheResults, Object payload, Map<String, Object> headers) {
-        this(consumer, cacheResults, false, payload, headers);
+    public LazyBundleProvider(RequestConsumer consumer, boolean cacheResults, Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse) {
+        this(consumer, cacheResults, false, payload, headers, httpServletResponse);
     }
 
     /**
@@ -78,9 +80,10 @@ public LazyBundleProvider(RequestConsumer consumer, boolean cacheResults, Object
      * @param sort         sort results
      * @param payload      incoming payload
      * @param headers      incoming headers
+     * @param httpServletResponse HTTP servlet response
      */
-    public LazyBundleProvider(RequestConsumer consumer, boolean cacheResults, boolean sort, Object payload, Map<String, Object> headers) {
-        super(consumer, sort, payload, headers);
+    public LazyBundleProvider(RequestConsumer consumer, boolean cacheResults, boolean sort, Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse) {
+        super(consumer, sort, payload, headers, httpServletResponse);
         this.cacheResults = cacheResults;
     }
 

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/RequestConsumer.java

@@ -20,6 +20,7 @@
 import ca.uhn.fhir.rest.api.MethodOutcome;
 import ca.uhn.fhir.rest.api.server.IBundleProvider;
 import ca.uhn.fhir.rest.api.server.RequestDetails;
+import jakarta.servlet.http.HttpServletResponse;
 import org.hl7.fhir.instance.model.api.IBaseBundle;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 
@@ -37,7 +38,7 @@
  * on searches.
  * <ul>
  * <li>{@link Constants#FHIR_REQUEST_SIZE_ONLY}: if this entry is present, the requester expects only
- * the result size to be returned in an parameter entry with the same name and calls {@link #handleSizeRequest(Object, Map)}
+ * the result size to be returned in an parameter entry with the same name and calls {@link #handleSizeRequest(Object, Map, Map)}
  * to do so. If possible, implementations should only request the result size from the backend rather than
  * a complete result set.</li>
  * <li>{@link Constants#FHIR_FROM_INDEX} and {@link Constants#FHIR_TO_INDEX}: if these entries are present,
@@ -71,22 +72,24 @@ default boolean test(RequestDetails requestDetails) {
     /**
      * Handles a Create / Update / Validate / Delete action request.
      *
-     * @param payload request payload
-     * @param headers request parameters, e.g. search parameters
+     * @param payload    request payload
+     * @param inHeaders  request parameters, e.g. search parameters
+     * @param outHeaders map where Camel response headers will be copied into
      * @return result of the action execution
      */
-    MethodOutcome handleAction(Object payload, Map<String, Object> headers);
+    MethodOutcome handleAction(Object payload, Map<String, Object> inHeaders, Map<String, Object> outHeaders);
 
     /**
      * Handles the request for a resource
      *
      * @param payload    request payload
-     * @param headers    request parameters, e.g. search parameters
+     * @param inHeaders  request parameters, e.g. search parameters
+     * @param outHeaders map where Camel response headers will be copied into
      * @param resultType type of the returned resource
      * @param <R>        type of the returned resource
      * @return resource to be returned
      */
-    <R extends IBaseResource> R handleResourceRequest(Object payload, Map<String, Object> headers, Class<R> resultType);
+    <R extends IBaseResource> R handleResourceRequest(Object payload, Map<String, Object> inHeaders, Map<String, Object> outHeaders, Class<R> resultType);
 
     /**
      * Handles the (search) request for a bundle, effectively being a list of resources.
@@ -96,32 +99,35 @@ default boolean test(RequestDetails requestDetails) {
      * indicating that only a part of the result is requested. Implementations must return only the requested entries.
      * </p>
      *
-     * @param payload request payload
-     * @param headers request parameters, e.g. search parameters or
-     * @param <R>     type of the returned resources contained in the bundle
+     * @param payload    request payload
+     * @param inHeaders  request parameters, e.g. search parameters or
+     * @param outHeaders map where Camel response headers will be copied into
+     * @param <R>        type of the returned resources contained in the bundle
      * @return list of resources to be returned
      */
-    <R extends IBaseResource> List<R> handleBundleRequest(Object payload, Map<String, Object> headers);
+    <R extends IBaseResource> List<R> handleBundleRequest(Object payload, Map<String, Object> inHeaders, Map<String, Object> outHeaders);
 
     /**
      * Handles the request for a bundle provider, effectively constructing a list of resources. The returned
      * IBundleProvider takes over the responsibility to fetch the required subset of the result, usually
-     * by indirectly calling {@link #handleBundleRequest(Object, Map)} as required.
+     * by indirectly calling {@link #handleBundleRequest(Object, Map, Map)} as required.
      *
      * @param payload request payload
      * @param headers request parameters, e.g. search parameters
+     * @param httpServletResponse HTTP servlet response
      * @return a bundle provider
      */
-    IBundleProvider handleBundleProviderRequest(Object payload, Map<String, Object> headers);
+    IBundleProvider handleBundleProviderRequest(Object payload, Map<String, Object> headers, HttpServletResponse httpServletResponse);
 
     /**
      * Handles transaction requests
      *
-     * @param payload request payload
-     * @param headers request parameters
+     * @param payload    request payload
+     * @param inHeaders  request parameters
+     * @param outHeaders map where Camel response headers will be copied into
      * @return transaction response bundle
      */
-    <T extends IBaseBundle> T handleTransactionRequest(Object payload, Map<String, Object> headers, Class<T> bundleClass);
+    <T extends IBaseBundle> T handleTransactionRequest(Object payload, Map<String, Object> inHeaders, Map<String, Object> outHeaders, Class<T> bundleClass);
 
     /**
      * Optional method that request the result size of a bundle request. Only used for lazy

commons/ihe/fhir/core/src/main/java/org/openehealth/ipf/commons/ihe/fhir/SharedFhirProvider.java

@@ -26,6 +26,7 @@
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Optional;
 
@@ -94,8 +95,11 @@ protected final <T extends IBaseBundle> T requestTransaction(
             RequestDetails requestDetails) {
         var consumer = getRequestConsumer(requestDetails).orElseThrow(() ->
                 new InvalidRequestException("Request does not match any consumer or consumers are not initialized"));
-        var headers = enrichParameters(null, httpServletRequest, requestDetails);
-        return consumer.handleTransactionRequest(payload, headers, bundleClass);
+        var inHeaders = enrichParameters(null, httpServletRequest, requestDetails);
+        var outHeaders = new HashMap<String, Object>();
+        T bundle = consumer.handleTransactionRequest(payload, inHeaders, outHeaders, bundleClass);
+        processOutHeaders(outHeaders, httpServletResponse);
+        return bundle;
     }
 
     /**

commons/ihe/fhir/core/src/test/java/org/openehealth/ipf/commons/ihe/fhir/EagerBundleProviderTest.java

@@ -16,6 +16,7 @@
 
 package org.openehealth.ipf.commons.ihe.fhir;
 
+import io.undertow.servlet.spec.HttpServletResponseImpl;
 import org.easymock.EasyMock;
 import org.hl7.fhir.dstu3.model.Patient;
 import org.hl7.fhir.instance.model.api.IBaseResource;
@@ -48,20 +49,20 @@ public void setup() {
         }
         var payload = new Object();
         var headers = new HashMap<String, Object>();
-        bundleProvider = new EagerBundleProvider(requestConsumer, payload, headers);
+        bundleProvider = new EagerBundleProvider(requestConsumer, payload, headers, new HttpServletResponseImpl(null, null));
     }
 
     @Test
     public void testGetSize() {
-        EasyMock.expect(requestConsumer.handleBundleRequest(bundleProvider.getPayload(), bundleProvider.getHeaders())).andReturn(response);
+        EasyMock.expect(requestConsumer.handleBundleRequest(bundleProvider.getPayload(), bundleProvider.getHeaders(), new HashMap<>())).andReturn(response);
         EasyMock.replay(requestConsumer);
         assertEquals(response.size(), bundleProvider.size().intValue());
         EasyMock.verify(requestConsumer);
     }
 
     @Test
     public void testGetResources() {
-        EasyMock.expect(requestConsumer.handleBundleRequest(bundleProvider.getPayload(), bundleProvider.getHeaders())).andReturn(response);
+        EasyMock.expect(requestConsumer.handleBundleRequest(bundleProvider.getPayload(), bundleProvider.getHeaders(), new HashMap<>())).andReturn(response);
         EasyMock.replay(requestConsumer);
         var result = bundleProvider.getResources(10, 30);
         Assertions.assertEquals(response.subList(10, 30), result);