Jersey example with multipart file upload support (#1555)

servicetalk-examples/http/jaxrs/build.gradle

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2019 Apple Inc. and the ServiceTalk project authors
+ * Copyright © 2019, 2021 Apple Inc. and the ServiceTalk project authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@ dependencies {
   implementation project(":servicetalk-data-jackson-jersey")
   implementation project(":servicetalk-http-netty")
   implementation project(":servicetalk-http-router-jersey")
+  implementation "org.glassfish.jersey.media:jersey-media-multipart:$jerseyVersion"
   implementation "org.slf4j:slf4j-api:$slf4jVersion"
 
   runtimeOnly "org.apache.logging.log4j:log4j-slf4j-impl:$log4jVersion"

servicetalk-examples/http/jaxrs/src/main/java/io/servicetalk/examples/http/jaxrs/HelloWorldJaxRsApplication.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2018 Apple Inc. and the ServiceTalk project authors
+ * Copyright © 2018, 2021 Apple Inc. and the ServiceTalk project authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,9 +15,14 @@
  */
 package io.servicetalk.examples.http.jaxrs;
 
+import org.glassfish.jersey.media.multipart.MultiPartFeature;
+
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.Set;
 import javax.ws.rs.core.Application;
 
+import static java.util.Arrays.asList;
 import static java.util.Collections.singleton;
 
 /**
@@ -26,6 +31,10 @@
 public class HelloWorldJaxRsApplication extends Application {
     @Override
     public Set<Class<?>> getClasses() {
-        return singleton(HelloWorldJaxRsResource.class);
+        return new HashSet<>(asList(
+                MultiPartFeature.class,
+                HelloWorldJaxRsResource.class
+            )
+        );
     }
 }

servicetalk-examples/http/jaxrs/src/main/java/io/servicetalk/examples/http/jaxrs/HelloWorldJaxRsResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2018 Apple Inc. and the ServiceTalk project authors
+ * Copyright © 2018, 2021 Apple Inc. and the ServiceTalk project authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,10 +17,14 @@
 
 import io.servicetalk.buffer.api.Buffer;
 import io.servicetalk.buffer.api.BufferAllocator;
+import io.servicetalk.buffer.api.CompositeBuffer;
 import io.servicetalk.concurrent.api.Publisher;
 import io.servicetalk.concurrent.api.Single;
 import io.servicetalk.transport.api.ConnectionContext;
 
+import org.glassfish.jersey.media.multipart.FormDataParam;
+
+import java.io.InputStream;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
@@ -36,10 +40,12 @@
 import javax.ws.rs.core.Response;
 
 import static io.servicetalk.concurrent.api.Publisher.from;
+import static io.servicetalk.concurrent.api.Publisher.fromInputStream;
 import static java.lang.Math.random;
 import static java.util.Collections.singletonMap;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static javax.ws.rs.core.MediaType.APPLICATION_JSON;
+import static javax.ws.rs.core.MediaType.MULTIPART_FORM_DATA;
 import static javax.ws.rs.core.MediaType.TEXT_PLAIN;
 import static javax.ws.rs.core.Response.accepted;
 import static javax.ws.rs.core.Response.ok;
@@ -145,6 +151,33 @@ public Single<Buffer> hello(final Single<Buffer> who,
                 .addBuffer(allocator.fromAscii("!")));
     }
 
+    /**
+     * Resource that relies on multi-part file upload on the consume side, and {@link Publisher} with
+     * operators for processing it on the produce side.
+     * <p>
+     * Test with:
+     * <pre>
+     * echo "An empty file" > sample.txt && curl -vF "file=@sample.txt" \
+     * http://localhost:8080/greetings/multipart-hello
+     * </pre>
+     *
+     * @param ctx the {@link ConnectionContext}.
+     * @param file the multi-part file contents.
+     * @return greetings as a {@link Single} {@link Buffer}.
+     */
+    @POST
+    @Path("multipart-hello")
+    @Consumes(MULTIPART_FORM_DATA)
+    @Produces(TEXT_PLAIN)
+    public Single<Buffer> multipartHello(@Context final ConnectionContext ctx,
+                                         @FormDataParam("file") InputStream file) {
+        final BufferAllocator allocator = ctx.executionContext().bufferAllocator();
+        return from(allocator.fromAscii("Hello multipart! Content: "))
+                .concat(fromInputStream(file).map(allocator::wrap))
+                .collect(allocator::newCompositeBuffer,
+                        (collector, item) -> ((CompositeBuffer) collector).addBuffer(item));
+    }
+
     /**
      * Resource that only relies on {@link Single}/{@link Publisher} for consuming and producing data,
      * and returns a JAX-RS {@link Response} in order to set its status.