Allow retrieving headers from response filters, via RequestView.

4 files changed, 100 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;
diff --git a/jdisc_http_service/src/test/java/com/yahoo/jdisc/http/filter/RequestViewImplTest.java b/jdisc_http_service/src/test/java/com/yahoo/jdisc/http/filter/RequestViewImplTest.java
new file mode 100644
index 00000000000..7ba40a04253
--- /dev/null
+++ b/jdisc_http_service/src/test/java/com/yahoo/jdisc/http/filter/RequestViewImplTest.java
@@ -0,0 +1,54 @@
+// Copyright 2017 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.jdisc.http.filter;
+
+import com.google.common.collect.Lists;
+import com.yahoo.jdisc.HeaderFields;
+import com.yahoo.jdisc.Request;
+import com.yahoo.jdisc.http.filter.SecurityResponseFilterChain.RequestViewImpl;
+import org.testng.annotations.Test;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.testng.Assert.assertEquals;
+
+/**
+ * @author gjoranv
+ */
+public class RequestViewImplTest {
+
+    @Test
+    public void header_from_the_parent_request_is_available() throws Exception {
+        final String HEADER = "single-header";
+
+        HeaderFields parentHeaders = new HeaderFields();
+        parentHeaders.add(HEADER, "value");
+
+        Request request = mock(Request.class);
+        when(request.headers()).thenReturn(parentHeaders);
+
+        RequestView requestView = new RequestViewImpl(request);
+
+        assertEquals(requestView.getFirstHeader(HEADER).get(), "value");
+        assertEquals(requestView.getHeaders(HEADER).size(), 1);
+        assertEquals(requestView.getHeaders(HEADER).get(0), "value");
+    }
+
+    @Test
+    public void multi_value_header_from_the_parent_request_is_available() throws Exception {
+        final String HEADER = "list-header";
+
+        HeaderFields parentHeaders = new HeaderFields();
+        parentHeaders.add(HEADER, Lists.newArrayList("one", "two"));
+
+        Request request = mock(Request.class);
+        when(request.headers()).thenReturn(parentHeaders);
+
+        RequestView requestView = new RequestViewImpl(request);
+
+        assertEquals(requestView.getHeaders(HEADER).size(), 2);
+        assertEquals(requestView.getHeaders(HEADER).get(0), "one");
+        assertEquals(requestView.getHeaders(HEADER).get(1), "two");
+
+        assertEquals(requestView.getFirstHeader(HEADER).get(), "one");
+    }
+}