2.x: Fix #44: streaming example fails to start

examples/webserver/streaming/README.md

@@ -14,6 +14,6 @@ java -jar target/helidon-examples-webserver-streaming.jar
 
 Upload a file and download it back with `curl`:
 ```shell
-curl --data-binary "@target/classes/large-file.bin" http://localhost:8080/upload
-curl http://localhost:8080/download
+curl --data-binary "@large-file.bin" http://localhost:8080/upload
+curl http://localhost:8080/download --output myfile.bin
 ```

examples/webserver/streaming/pom.xml

@@ -57,8 +57,13 @@
             <scope>test</scope>
         </dependency>
         <dependency>
-            <groupId>io.helidon.webserver</groupId>
-            <artifactId>helidon-webserver-test-support</artifactId>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.webclient</groupId>
+            <artifactId>helidon-webclient</artifactId>
             <scope>test</scope>
         </dependency>
     </dependencies>

examples/webserver/streaming/src/main/java/io/helidon/webserver/examples/streaming/Main.java

@@ -24,8 +24,6 @@
  */
 public class Main {
 
-    static final String LARGE_FILE_RESOURCE = "/large-file.bin";
-
     private Main() {
     }
 

examples/webserver/streaming/src/main/java/io/helidon/webserver/examples/streaming/StreamingService.java

@@ -16,52 +16,87 @@
 
 package io.helidon.webserver.examples.streaming;
 
-import java.net.URISyntaxException;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.channels.ReadableByteChannel;
+import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
+import io.helidon.common.configurable.ScheduledThreadPoolSupplier;
+import io.helidon.common.http.DataChunk;
+import io.helidon.common.http.Http;
+import io.helidon.common.reactive.IoMulti;
 import io.helidon.webserver.Routing;
 import io.helidon.webserver.ServerRequest;
 import io.helidon.webserver.ServerResponse;
 import io.helidon.webserver.Service;
 
-import static io.helidon.webserver.examples.streaming.Main.LARGE_FILE_RESOURCE;
-
 /**
  * StreamingService class. Uses a {@code Subscriber<RequestChunk>} and a
  * {@code Publisher<ResponseChunk>} for uploading and downloading files.
  */
 public class StreamingService implements Service {
     private static final Logger LOGGER = Logger.getLogger(StreamingService.class.getName());
-
-    private final Path filePath;
+    private final ScheduledExecutorService executor = ScheduledThreadPoolSupplier.create().get();
+    private volatile Path filePath;
 
     StreamingService() {
-        try {
-            filePath = Paths.get(getClass().getResource(LARGE_FILE_RESOURCE).toURI());
-        } catch (URISyntaxException e) {
-            throw new RuntimeException(e);
-        }
     }
 
     @Override
     public void update(Routing.Rules routingRules) {
         routingRules.get("/download", this::download)
-                .post("/upload", this::upload);
+                    .post("/upload", this::upload);
     }
 
     private void upload(ServerRequest request, ServerResponse response) {
         LOGGER.info("Entering upload ... " + Thread.currentThread());
-        request.content().subscribe(new ServerFileWriter(response));
+        Path tempFilePath = createTempFile("large-file", ".tmp");
+        filePath = tempFilePath;
+        LOGGER.info("Storing upload as " + tempFilePath);
+        request.content()
+               .map(DataChunk::data)
+               .flatMapIterable(Arrays::asList)
+               .to(IoMulti.writeToFile(tempFilePath)
+                          .executor(executor)
+                          .build())
+               .thenRun(() -> response.status(Http.Status.OK_200).send());
         LOGGER.info("Exiting upload ...");
     }
 
     private void download(ServerRequest request, ServerResponse response) {
         LOGGER.info("Entering download ..." + Thread.currentThread());
+        if (filePath == null) {
+            LOGGER.warning("No file to download.");
+            response.status(Http.Status.BAD_REQUEST_400).send("No file to download. Please upload file first.");
+            return;
+        }
         long length = filePath.toFile().length();
-        response.headers().add("Content-Length", String.valueOf(length));
-        response.send(new ServerFileReader(filePath));
-        LOGGER.info("Exiting download ...");
+        response.headers().contentLength(length);
+        response.send(IoMulti.multiFromByteChannelBuilder(newByteChannel(filePath))
+                             .executor(executor)
+                             .build()
+                             .map(DataChunk::create));
+        LOGGER.info("Exiting download. Returning " + length + " bytes...");
+    }
+
+    @SuppressWarnings("SameParameterValue")
+    private static Path createTempFile(String prefix, String suffix) {
+        try {
+            return Files.createTempFile(prefix, suffix);
+        } catch (IOException ex) {
+            throw new UncheckedIOException(ex);
+        }
+    }
+
+    private static ReadableByteChannel newByteChannel(Path path) {
+        try {
+            return Files.newByteChannel(path);
+        } catch (IOException ex) {
+            throw new UncheckedIOException(ex);
+        }
     }
 }