Fixes problems converting HTTP/2 headers to Metadata and vice versa. Adds new test. (#10300)

Author: spericas

webserver/grpc/pom.xml

@@ -87,8 +87,9 @@
             <scope>test</scope>
         </dependency>
         <dependency>
-            <groupId>io.helidon.codegen</groupId>
-            <artifactId>helidon-codegen</artifactId>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
         </dependency>
     </dependencies>
 

webserver/grpc/src/main/java/io/helidon/webserver/grpc/GrpcHeadersUtil.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 Oracle and/or its affiliates.
+ * Copyright (c) 2024, 2025 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,15 +31,19 @@ class GrpcHeadersUtil {
     private GrpcHeadersUtil() {
     }
 
-    static void updateHeaders(WritableHeaders<?> writable, Metadata headers) {
+    static void updateHeaders(WritableHeaders<?> headers, Metadata metadata) {
         Base64.Encoder encoder = Base64.getEncoder();
-        headers.keys().forEach(name -> {
+        metadata.keys().forEach(name -> {
             if (name.endsWith(Metadata.BINARY_HEADER_SUFFIX)) {
-                byte[] binary = headers.get(Metadata.Key.of(name, Metadata.BINARY_BYTE_MARSHALLER));
-                writable.add(HeaderNames.create(name, new String(encoder.encode(binary), US_ASCII)));
+                Metadata.Key<byte[]> key = Metadata.Key.of(name, Metadata.BINARY_BYTE_MARSHALLER);
+                byte[] binary = metadata.get(key);
+                headers.add(HeaderNames.create(name, new String(encoder.encode(binary), US_ASCII)));
             } else {
-                String ascii = headers.get(Metadata.Key.of(name, Metadata.ASCII_STRING_MARSHALLER));
-                writable.add(HeaderNames.create(name, ascii));
+                Metadata.Key<String> key = Metadata.Key.of(name, Metadata.ASCII_STRING_MARSHALLER);
+                Iterable<String> ascii = metadata.getAll(key);
+                if (ascii != null) {
+                    ascii.forEach(v -> headers.add(HeaderNames.create(name), v));
+                }
             }
         });
     }
@@ -50,10 +54,11 @@ static Metadata toMetadata(Http2Headers headers) {
         headers.httpHeaders().forEach(header -> {
             String name = header.name();
             if (name.endsWith(Metadata.BINARY_HEADER_SUFFIX)) {
-                metadata.put(Metadata.Key.of(name, Metadata.BINARY_BYTE_MARSHALLER),
-                             decoder.decode(name.getBytes(US_ASCII)));
+                Metadata.Key<byte[]> key = Metadata.Key.of(name, Metadata.BINARY_BYTE_MARSHALLER);
+                metadata.put(key, decoder.decode(header.valueBytes()));
             } else {
-                metadata.put(Metadata.Key.of(name, Metadata.ASCII_STRING_MARSHALLER), name);
+                Metadata.Key<String> key = Metadata.Key.of(name, Metadata.ASCII_STRING_MARSHALLER);
+                header.allValues().forEach(value -> metadata.put(key, value));
             }
         });
         return metadata;

webserver/grpc/src/test/java/io/helidon/webserver/grpc/GrpcHeadersUtilTest.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2025 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.helidon.webserver.grpc;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import io.helidon.http.HeaderNames;
+import io.helidon.http.WritableHeaders;
+import io.helidon.http.http2.Http2Headers;
+
+import io.grpc.Metadata;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.CoreMatchers.hasItem;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+class GrpcHeadersUtilTest {
+
+    @Test
+    void testUpdateHeaders() {
+        Metadata metadata = new Metadata();
+        Metadata.Key<String> key = Metadata.Key.of("cookie", Metadata.ASCII_STRING_MARSHALLER);
+        metadata.put(key, "sugar");
+        metadata.put(key, "almond");
+        WritableHeaders<?> headers = WritableHeaders.create();
+        GrpcHeadersUtil.updateHeaders(headers, metadata);
+        assertThat(headers.size(), is(2));
+        List<String> values = headers.get(HeaderNames.COOKIE).allValues();
+        assertThat(values, hasItem("sugar"));
+        assertThat(values, hasItem("almond"));
+    }
+
+    @Test
+    void testToMetadata() {
+        WritableHeaders<?> headers = WritableHeaders.create();
+        headers.add(HeaderNames.COOKIE, "sugar", "almond");
+        Http2Headers http2Headers = mock(Http2Headers.class);
+        when(http2Headers.httpHeaders()).thenReturn(headers);
+        Metadata metadata = GrpcHeadersUtil.toMetadata(http2Headers);
+        Metadata.Key<String> key = Metadata.Key.of("cookie", Metadata.ASCII_STRING_MARSHALLER);
+        assertThat(metadata.containsKey(key), is(true));
+        Set<String> values = new HashSet<>();
+        metadata.getAll(key).forEach(values::add);
+        assertThat(values, hasItem("sugar"));
+        assertThat(values, hasItem("almond"));
+    }
+}