Add BearerTokenAuthenticationInterceptor for client

samples/grpc-tomcat-secure/src/test/java/org/springframework/grpc/sample/GrpcServerApplicationTests.java

@@ -3,6 +3,8 @@ package org.springframework.grpc.sample;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.util.List;
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.junit.jupiter.api.Test;
@@ -69,10 +71,8 @@ public class GrpcServerApplicationTests {
 		@Bean
 		@Lazy
 		SimpleGrpc.SimpleBlockingStub basic(GrpcChannelFactory channels, @LocalServerPort int port) {
-			return SimpleGrpc.newBlockingStub(channels.createChannel("0.0.0.0:" + port,
-					ChannelBuilderOptions.defaults()
-						.withCustomizer((authority, channel) -> channel
-							.intercept(new BasicAuthenticationInterceptor("user", "user")))));
+			return SimpleGrpc.newBlockingStub(channels.createChannel("0.0.0.0:" + port, ChannelBuilderOptions.defaults()
+				.withInterceptors(List.of(new BasicAuthenticationInterceptor("user", "user")))));
 		}
 
 		@Bean

spring-grpc-core/src/main/java/org/springframework/grpc/client/security/BearerTokenAuthenticationInterceptor.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2024-2024 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.grpc.client.security;
+
+import java.util.function.Supplier;
+
+import org.springframework.grpc.server.security.GrpcSecurity;
+
+import io.grpc.CallOptions;
+import io.grpc.Channel;
+import io.grpc.ClientCall;
+import io.grpc.ClientInterceptor;
+import io.grpc.ForwardingClientCall.SimpleForwardingClientCall;
+import io.grpc.MethodDescriptor;
+
+/**
+ * An interceptor that adds bearer token authentication headers to gRPC client calls.
+ *
+ * @author Dave Syer
+ */
+public class BearerTokenAuthenticationInterceptor implements ClientInterceptor {
+
+	private final Supplier<String> token;
+
+	public BearerTokenAuthenticationInterceptor(String token) {
+		this(() -> token);
+	}
+
+	public BearerTokenAuthenticationInterceptor(Supplier<String> token) {
+		this.token = token;
+	}
+
+	@Override
+	public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(MethodDescriptor<ReqT, RespT> method,
+			CallOptions callOptions, Channel next) {
+		return new SimpleForwardingClientCall<ReqT, RespT>(next.newCall(method, callOptions)) {
+			public void start(ClientCall.Listener<RespT> responseListener, io.grpc.Metadata headers) {
+				headers.put(GrpcSecurity.AUTHORIZATION_KEY,
+						"Bearer " + BearerTokenAuthenticationInterceptor.this.token.get());
+				super.start(responseListener, headers);
+			};
+		};
+	}
+
+}