New simple SSE test that shows how to use the API in Helidon SE and a…

…lso shows how to interact with an SSE endpoint using WebClient.

examples/webserver/pom.xml

@@ -53,5 +53,6 @@
         <module>tracing</module>
         <module>tutorial</module>
         <module>websocket</module>
+        <module>sse</module>
     </modules>
 </project>

examples/webserver/sse/README.md

@@ -0,0 +1,17 @@
+# Helidon SE SSE Example
+
+This is a very simple example showing how to use the Helidon SSE API to send events from the
+server to a client. It defines a couple of SSE "hello world" endpoints that send either
+text or JSON messages. It also uses the SSE extensions to the Helidon WebClient API to test 
+these endpoints.
+
+## Build, run and test
+
+Build and start the server:
+```shell
+mvn package
+java -jar target/helidon-examples-webserver-sse.jar
+```
+
+See `SseServiceTest` for additional information on the tests that are executed during
+the build process.

examples/webserver/sse/pom.xml

@@ -0,0 +1,94 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+    Copyright (c) 2024 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.
+  -->
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>io.helidon.applications</groupId>
+        <artifactId>helidon-se</artifactId>
+        <version>4.2.0-SNAPSHOT</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>io.helidon.examples.webserver</groupId>
+    <artifactId>helidon-examples-webserver-sse</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+    <name>Helidon Examples WebServer SSE</name>
+
+    <properties>
+        <mainClass>io.helidon.examples.webserver.sse.SseMain</mainClass>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.helidon.webserver</groupId>
+            <artifactId>helidon-webserver</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.webserver</groupId>
+            <artifactId>helidon-webserver-sse</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.webclient</groupId>
+            <artifactId>helidon-webclient-sse</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.http.media</groupId>
+            <artifactId>helidon-http-media-jsonp</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>jakarta.json</groupId>
+            <artifactId>jakarta.json-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.http.media</groupId>
+            <artifactId>helidon-http-media-jsonb</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.webserver.testing.junit5</groupId>
+            <artifactId>helidon-webserver-testing-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-all</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-dependency-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>copy-libs</id>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

examples/webserver/sse/src/main/java/io/helidon/examples/webserver/sse/SseMain.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2024 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.examples.webserver.sse;
+
+import io.helidon.webserver.WebServer;
+import io.helidon.webserver.http.HttpRouting;
+
+class SseMain {
+
+    private SseMain() {
+    }
+
+    public static void main(String[] args) {
+        WebServer.builder()
+                .port(8080)
+                .routing(HttpRouting.builder().register(new SseService()))
+                .build()
+                .start();
+    }
+}

examples/webserver/sse/src/main/java/io/helidon/examples/webserver/sse/SseService.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2024 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.examples.webserver.sse;
+
+import io.helidon.http.sse.SseEvent;
+import io.helidon.webserver.http.HttpRules;
+import io.helidon.webserver.http.HttpService;
+import io.helidon.webserver.http.ServerRequest;
+import io.helidon.webserver.http.ServerResponse;
+import io.helidon.webserver.sse.SseSink;
+
+import jakarta.json.Json;
+import jakarta.json.JsonObject;
+
+class SseService implements HttpService {
+
+    @Override
+    public void routing(HttpRules httpRules) {
+        httpRules.get("/sse_text", this::sseText)
+                .get("/sse_json", this::sseJson);
+    }
+
+    void sseText(ServerRequest req, ServerResponse res) {
+        try (SseSink sseSink = res.sink(SseSink.TYPE)) {
+            sseSink.emit(SseEvent.builder()
+                                 .comment("first line")
+                                 .name("first")
+                                 .data("hello")
+                                 .build())
+                    .emit(SseEvent.builder()
+                                  .name("second")
+                                  .data("world")
+                                  .build());
+        }
+    }
+
+    void sseJson(ServerRequest req, ServerResponse res) {
+        JsonObject json = Json.createObjectBuilder()
+                .add("hello", "world")
+                .build();
+        try (SseSink sseSink = res.sink(SseSink.TYPE)) {
+            sseSink.emit(SseEvent.create(json));
+        }
+    }
+}

examples/webserver/sse/src/main/java/io/helidon/examples/webserver/sse/package-info.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2024 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.examples.webserver.sse;

examples/webserver/sse/src/test/java/io/helidon/examples/webserver/sse/SseServiceTest.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2024 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.examples.webserver.sse;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import io.helidon.http.sse.SseEvent;
+import io.helidon.webclient.http1.Http1Client;
+import io.helidon.webclient.http1.Http1ClientResponse;
+import io.helidon.webclient.sse.SseSource;
+import io.helidon.webserver.http.HttpRules;
+import io.helidon.webserver.testing.junit5.ServerTest;
+import io.helidon.webserver.testing.junit5.SetUpRoute;
+
+import jakarta.json.JsonObject;
+import org.junit.jupiter.api.Test;
+
+import static io.helidon.http.HeaderValues.ACCEPT_EVENT_STREAM;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+@ServerTest
+class SseServiceTest {
+
+    private final Http1Client client;
+
+    SseServiceTest(Http1Client client) {
+        this.client = client;
+    }
+
+    @SetUpRoute
+    static void routing(HttpRules rules) {
+        rules.register(new SseService());
+    }
+
+    @Test
+    void testSseText() throws InterruptedException {
+        try (Http1ClientResponse r = client.get("/sse_text").header(ACCEPT_EVENT_STREAM).request()) {
+            CountDownLatch latch = new CountDownLatch(1);
+            r.source(SseSource.TYPE, new SseSource() {
+                private int state = 0;
+
+                @Override
+                public void onEvent(SseEvent event) {
+                    switch (state) {
+                    case 0 -> {
+                        assertThat(event.comment().isPresent(), is(true));
+                        assertThat(event.comment().get(), is("first line"));
+                        assertThat(event.name().isPresent(), is(true));
+                        assertThat(event.name().get(), is("first"));
+                        assertThat(event.data(), is("hello"));
+                    }
+                    case 1 -> {
+                        assertThat(event.name().isPresent(), is(true));
+                        assertThat(event.name().get(), is("second"));
+                        assertThat(event.data(), is("world"));
+                    }
+                    }
+                    state++;
+                }
+
+                @Override
+                public void onClose() {
+                    latch.countDown();
+                }
+            });
+            assertThat(latch.await(5, TimeUnit.SECONDS), is(true));
+        }
+    }
+
+    @Test
+    void testSseJson() throws InterruptedException {
+        try (Http1ClientResponse r = client.get("/sse_json").header(ACCEPT_EVENT_STREAM).request()) {
+            CountDownLatch latch = new CountDownLatch(1);
+            r.source(SseSource.TYPE, event -> {
+                JsonObject json = event.data(JsonObject.class);
+                assertThat(json, is(notNullValue()));
+                assertThat(json.getString("hello"), is("world"));
+                latch.countDown();
+            });
+            assertThat(latch.await(5, TimeUnit.SECONDS), is(true));
+        }
+    }
+}