Add unary-first SDK-native gRPC client transport on Restlet

changes.md

@@ -81,6 +81,14 @@ Changes log
           supporting helper class. Applications with multiple STDIO protocol helpers must
           select one explicitly.
     - Enhancements
+        - Added an experimental SDK-native gRPC unary client on a borrowed Restlet HTTP/2
+          connector, with explicit plaintext opt-in, bounded messages and call admission.
+          Regression tests cover authority mapping, cancellation before and after headers,
+          disconnect recovery, malformed responses and shared connector ownership. Empty
+          responses retain SDK missing-status diagnostics instead of failing on a null stream.
+          Shutdown arriving before SDK listener installation is replayed once; interrupted
+          shutdown still closes owned transport resources and preserves the interrupt.
+          TLS, streaming methods and physical gRPC connection controls remain unsupported.
         - Added the supported `org.restlet.util.StreamTransport` seam for protocol-neutral,
           bounded synchronous byte I/O, serialized writes, borrowed-stream cancellation and
           owned subprocess lifecycle with separate bounded stderr capture. No protocol

org.restlet.ext.grpc/pom.xml

@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.restlet</groupId>
+        <artifactId>org.restlet.parent</artifactId>
+        <version>3.0.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>org.restlet.ext.grpc</artifactId>
+    <name>Restlet Framework - gRPC extension</name>
+    <description>Native gRPC unary client on a borrowed Restlet HTTP/2 connector.</description>
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>com.google.guava</groupId>
+                <artifactId>guava</artifactId>
+                <version>33.6.0-android</version>
+            </dependency>
+            <dependency>
+                <groupId>com.google.errorprone</groupId>
+                <artifactId>error_prone_annotations</artifactId>
+                <version>2.50.0</version>
+            </dependency>
+            <dependency>
+                <groupId>io.grpc</groupId>
+                <artifactId>grpc-bom</artifactId>
+                <version>${lib-grpc-version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    <dependencies>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.restlet</groupId>
+            <artifactId>org.restlet</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-core</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-stub</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-protobuf</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-netty-shaded</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-services</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${lib-junit-version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

org.restlet.ext.grpc/src/main/java/module-info.java

@@ -0,0 +1,17 @@
+/**
+ * Copyright 2005-2026 Qlik
+ *
+ * <p>The content of this file is subject to the terms of the Apache 2.0 open source license
+ * available at https://www.opensource.org/licenses/apache-2.0
+ *
+ * <p>Restlet is a registered trademark of QlikTech International AB.
+ */
+@SuppressWarnings({"requires-automatic", "requires-transitive-automatic"})
+module org.restlet.ext.grpc {
+    requires transitive org.restlet;
+    requires transitive io.grpc;
+    requires io.grpc.internal;
+    requires com.google.common;
+
+    exports org.restlet.ext.grpc;
+}