Allow retrieving headers from response filters, via RequestView.

3 files changed, 46 insertions, 4 deletions

diff --git a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/RequestView.java b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/RequestView.java
index f03a16f0bf0..dcee10cede2 100644
--- a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/RequestView.java
+++ b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/RequestView.java
@@ -3,7 +3,9 @@ package com.yahoo.jdisc.http.filter;
 
 import com.yahoo.jdisc.http.HttpRequest.Method;
 
+import javax.annotation.Nonnull;
 import java.net.URI;
+import java.util.List;
 import java.util.Optional;
 
 /**
@@ -20,13 +22,26 @@ public interface RequestView {
      * @see com.yahoo.jdisc.Request#context()
      * @return the named data associated with the request that are private to this runtime (not exposed to the client)
      */
-    public Object getAttribute(String name);
+    Object getAttribute(String name);
+
+    /**
+     * Returns an immutable view of all values of a named header field.
+     * Returns an empty list if no such header is present.
+     */
+    @Nonnull
+    List<String> getHeaders(String name);
+
+    /**
+     * Convenience method for retrieving the first value of a named header field.
+     * Returns empty if the header is not set, or if the value list is empty.
+     */
+    Optional<String> getFirstHeader(String name);
 
     /**
      * Returns the Http method. Only present if the underlying request has http-like semantics.
      */
-    public Optional<Method> getMethod();
+    Optional<Method> getMethod();
 
-    public URI getUri();
+    URI getUri();
 
 }
diff --git a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityFilterInvoker.java b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityFilterInvoker.java
index 2bcb1635dfb..2b53402451c 100644
--- a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityFilterInvoker.java
+++ b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityFilterInvoker.java
@@ -9,9 +9,12 @@ import com.yahoo.jdisc.http.servlet.ServletRequest;
 import com.yahoo.jdisc.http.servlet.ServletResponse;
 import com.yahoo.jdisc.http.server.jetty.FilterInvoker;
 
+import javax.annotation.Nonnull;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.net.URI;
+import java.util.Collections;
+import java.util.List;
 import java.util.Optional;
 
 /**
@@ -82,6 +85,17 @@ public class SecurityFilterInvoker implements FilterInvoker {
             return request.getAttribute(name);
         }
 
+
+        @Nonnull @Override
+        public List<String> getHeaders(String name) {
+            return Collections.unmodifiableList(Collections.list(request.getHeaders(name)));
+        }
+
+        @Override
+        public Optional<String> getFirstHeader(String name) {
+            return getHeaders(name).stream().findFirst();
+        }
+
         @Override
         public Optional<Method> getMethod() {
             return Optional.of(Method.valueOf(request.getMethod()));
diff --git a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityResponseFilterChain.java b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityResponseFilterChain.java
index ae4ea34e45c..ae03f5fcb59 100644
--- a/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityResponseFilterChain.java
+++ b/jdisc_http_service/src/main/java/com/yahoo/jdisc/http/filter/SecurityResponseFilterChain.java
@@ -14,6 +14,8 @@ import com.yahoo.jdisc.Response;
 import com.yahoo.jdisc.http.HttpRequest;
 import com.yahoo.jdisc.http.HttpResponse;
 
+import javax.annotation.Nonnull;
+
 /**
  * Implementation of TypedFilterChain for DiscFilterResponse
  * @author tejalk
@@ -58,7 +60,7 @@ public class SecurityResponseFilterChain extends AbstractResource implements Res
         return Collections.unmodifiableList(filters);
     }
 
-    private static class RequestViewImpl implements RequestView {
+    static class RequestViewImpl implements RequestView {
 
         private final Request request;
         private final Optional<HttpRequest.Method> method;
@@ -75,6 +77,17 @@ public class SecurityResponseFilterChain extends AbstractResource implements Res
             return request.context().get(name);
         }
 
+        @Nonnull @Override
+        public List<String> getHeaders(String name) {
+            List<String> headers = request.headers().get(name);
+            return headers == null ? Collections.emptyList() : Collections.unmodifiableList(headers);
+        }
+
+        @Override
+        public Optional<String> getFirstHeader(String name) {
+            return getHeaders(name).stream().findFirst();
+        }
+
         @Override
         public Optional<HttpRequest.Method> getMethod() {
             return method;