Add reading reactive multipart request support

This commit introduces reactive multipart support by adding a new
MultipartHttpMessageReader interface (with default methods) and a
SynchronossMultipartHttpMessageReader implementation based on
the Synchronoss NIO Multipart implementation
(https://github.com/synchronoss/nio-multipart).

Issue: SPR-14546

spring-web/src/test/java/org/springframework/http/codec/multipart/MultipartHttpMessageReaderTests.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2002-2017 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
+ *
+ *      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 org.springframework.http.codec.multipart;
+
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.http.MediaType;
+import org.springframework.util.MultiValueMap;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+
+/**
+ * @author Sebastien Deleuze
+ */
+public class MultipartHttpMessageReaderTests {
+
+	private MultipartHttpMessageReader reader;
+
+	@Before
+	public void setUp() throws Exception {
+		this.reader = (elementType, message, hints) -> {
+			throw new UnsupportedOperationException();
+		};
+	}
+
+	@Test
+	public void canRead() {
+		assertTrue(this.reader.canRead(
+				ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, Part.class),
+				MediaType.MULTIPART_FORM_DATA));
+
+		assertFalse(this.reader.canRead(
+				ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, Object.class),
+				MediaType.MULTIPART_FORM_DATA));
+
+		assertFalse(this.reader.canRead(
+				ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, String.class),
+				MediaType.MULTIPART_FORM_DATA));
+
+		assertFalse(this.reader.canRead(
+				ResolvableType.forClassWithGenerics(Map.class, String.class, String.class),
+				MediaType.MULTIPART_FORM_DATA));
+
+		assertFalse(this.reader.canRead(
+				ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, Part.class),
+				MediaType.APPLICATION_FORM_URLENCODED));
+	}
+
+}

spring-web/src/test/java/org/springframework/http/codec/multipart/SynchronossMultipartHttpMessageReaderTests.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright 2002-2017 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
+ *
+ *      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 org.springframework.http.codec.multipart;
+
+import java.io.IOException;
+import java.util.Optional;
+
+import static java.util.Collections.emptyMap;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import org.junit.Test;
+import static org.springframework.http.HttpHeaders.CONTENT_LENGTH;
+import static org.springframework.http.HttpHeaders.CONTENT_TYPE;
+import static org.springframework.http.MediaType.MULTIPART_FORM_DATA;
+import static org.springframework.http.codec.multipart.MultipartHttpMessageReader.*;
+
+import reactor.core.publisher.Flux;
+import reactor.test.StepVerifier;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+
+import org.springframework.http.MediaType;
+import org.springframework.http.MockHttpOutputMessage;
+import org.springframework.http.converter.FormHttpMessageConverter;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+
+/**
+ * @author Sebastien Deleuze
+ */
+public class SynchronossMultipartHttpMessageReaderTests {
+
+	@Test
+	public void resolveParts() throws IOException {
+		ServerHttpRequest request = generateMultipartRequest();
+		MultipartHttpMessageReader multipartReader = new SynchronossMultipartHttpMessageReader();
+		MultiValueMap<String, Part> parts = multipartReader.readMono(MULTIPART_VALUE_TYPE, request, emptyMap()).block();
+		assertEquals(2, parts.size());
+
+		assertTrue(parts.containsKey("fooPart"));
+		Part part = parts.getFirst("fooPart");
+		assertEquals("fooPart", part.getName());
+		Optional<String> filename = part.getFilename();
+		assertTrue(filename.isPresent());
+		assertEquals("foo.txt", filename.get());
+		DataBuffer buffer = part
+				.getContent()
+				.reduce((s1, s2) -> s1.write(s2))
+				.block();
+		assertEquals(12, buffer.readableByteCount());
+		byte[] byteContent = new byte[12];
+		buffer.read(byteContent);
+		assertEquals("Lorem\nIpsum\n", new String(byteContent));
+
+		assertTrue(parts.containsKey("barPart"));
+		part = parts.getFirst("barPart");
+		assertEquals("barPart", part.getName());
+		filename = part.getFilename();
+		assertFalse(filename.isPresent());
+		assertEquals("bar", part.getContentAsString().block());
+	}
+
+	@Test
+	public void bodyError() {
+		ServerHttpRequest request = generateErrorMultipartRequest();
+		MultipartHttpMessageReader multipartReader = new SynchronossMultipartHttpMessageReader();
+		StepVerifier.create(multipartReader.readMono(MULTIPART_VALUE_TYPE, request, emptyMap()))
+				.verifyError();
+	}
+
+	private ServerHttpRequest generateMultipartRequest() throws IOException {
+		HttpHeaders fooHeaders = new HttpHeaders();
+		fooHeaders.setContentType(MediaType.TEXT_PLAIN);
+		ClassPathResource fooResource = new ClassPathResource("org/springframework/http/codec/multipart/foo.txt");
+		HttpEntity<ClassPathResource> fooPart = new HttpEntity<>(fooResource, fooHeaders);
+		HttpEntity<String> barPart = new HttpEntity<>("bar");
+		FormHttpMessageConverter converter = new FormHttpMessageConverter();
+		MockHttpOutputMessage outputMessage = new MockHttpOutputMessage();
+		MultiValueMap<String, Object> parts = new LinkedMultiValueMap<>();
+		parts.add("fooPart", fooPart);
+		parts.add("barPart", barPart);
+		converter.write(parts, MULTIPART_FORM_DATA, outputMessage);
+		byte[] content = outputMessage.getBodyAsBytes();
+		MockServerHttpRequest request = MockServerHttpRequest
+				.post("/foo")
+				.header(CONTENT_TYPE, outputMessage.getHeaders().getContentType().toString())
+				.header(CONTENT_LENGTH, String.valueOf(content.length))
+				.body(new String(content));
+		return request;
+	}
+
+	private ServerHttpRequest generateErrorMultipartRequest() {
+		DataBufferFactory bufferFactory = new DefaultDataBufferFactory();
+		MockServerHttpRequest request = MockServerHttpRequest
+				.post("/foo")
+				.header(CONTENT_TYPE, MULTIPART_FORM_DATA.toString())
+				.body(Flux.just(bufferFactory.wrap("invalid content".getBytes())));
+		return request;
+	}
+
+}