(Re)introduce DefaultMultipartMessageReader

This commit introduces the DefaultMultipartMessageReader, a fully
reactive multipart parser without third party dependencies.

An earlier version of this code was introduced in fb642ce, but removed
again in 77c24aa because of buffering issues.

Closes gh-21659

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

@@ -0,0 +1,373 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ *      https://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.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Stream;
+
+import io.netty.buffer.PooledByteBufAllocator;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.reactivestreams.Subscription;
+import reactor.core.Exceptions;
+import reactor.core.publisher.BaseSubscriber;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+
+import org.springframework.core.codec.DecodingException;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.io.buffer.DataBufferUtils;
+import org.springframework.core.io.buffer.NettyDataBufferFactory;
+import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
+import org.springframework.web.testfixture.http.server.reactive.MockServerHttpRequest;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.singletonMap;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.params.provider.Arguments.arguments;
+import static org.springframework.core.ResolvableType.forClass;
+import static org.springframework.core.io.buffer.DataBufferUtils.release;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class DefaultPartHttpMessageReaderTests  {
+
+	private static final String LOREM_IPSUM = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer iaculis metus id vestibulum nullam.";
+
+	private static final String MUSPI_MEROL = new StringBuilder(LOREM_IPSUM).reverse().toString();
+
+	private static final int BUFFER_SIZE = 64;
+
+	private static final DataBufferFactory bufferFactory = new NettyDataBufferFactory(new PooledByteBufAllocator());
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void canRead(String displayName, DefaultPartHttpMessageReader reader) {
+		assertThat(reader.canRead(forClass(Part.class), MediaType.MULTIPART_FORM_DATA)).isTrue();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void simple(String displayName, DefaultPartHttpMessageReader reader) throws InterruptedException {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("simple.multipart", getClass()), "simple-boundary");
+
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		CountDownLatch latch = new CountDownLatch(2);
+		StepVerifier.create(result)
+				.consumeNextWith(part -> testPart(part, null,
+						"This is implicitly typed plain ASCII text.\r\nIt does NOT end with a linebreak.", latch)).as("Part 1")
+				.consumeNextWith(part -> testPart(part, null,
+						"This is explicitly typed plain ASCII text.\r\nIt DOES end with a linebreak.\r\n", latch)).as("Part 2")
+				.verifyComplete();
+
+		latch.await();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void noHeaders(String displayName, DefaultPartHttpMessageReader reader) {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("no-header.multipart", getClass()), "boundary");
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+			StepVerifier.create(result)
+					.consumeNextWith(part -> {
+						assertThat(part.headers()).isEmpty();
+						part.content().subscribe(DataBufferUtils::release);
+					})
+					.verifyComplete();
+		}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void noEndBoundary(String displayName, DefaultPartHttpMessageReader reader) {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("no-end-boundary.multipart", getClass()), "boundary");
+
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		StepVerifier.create(result)
+				.expectError(DecodingException.class)
+				.verify();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void garbage(String displayName, DefaultPartHttpMessageReader reader) {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("garbage-1.multipart", getClass()), "boundary");
+
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		StepVerifier.create(result)
+				.expectError(DecodingException.class)
+				.verify();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void noEndHeader(String displayName, DefaultPartHttpMessageReader reader)  {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("no-end-header.multipart", getClass()), "boundary");
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		StepVerifier.create(result)
+				.expectError(DecodingException.class)
+				.verify();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void noEndBody(String displayName, DefaultPartHttpMessageReader reader) {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("no-end-body.multipart", getClass()), "boundary");
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		StepVerifier.create(result)
+				.expectError(DecodingException.class)
+				.verify();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void cancelPart(String displayName, DefaultPartHttpMessageReader reader) {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("simple.multipart", getClass()), "simple-boundary");
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		StepVerifier.create(result, 1)
+				.consumeNextWith(part -> part.content().subscribe(DataBufferUtils::release))
+				.thenCancel()
+				.verify();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void cancelBody(String displayName, DefaultPartHttpMessageReader reader) throws Exception {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("simple.multipart", getClass()), "simple-boundary");
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		CountDownLatch latch = new CountDownLatch(1);
+		StepVerifier.create(result, 1)
+				.consumeNextWith(part -> part.content().subscribe(new CancelSubscriber()))
+				.thenRequest(1)
+				.consumeNextWith(part -> testPart(part, null,
+						"This is explicitly typed plain ASCII text.\r\nIt DOES end with a linebreak.\r\n", latch)).as("Part 2")
+				.verifyComplete();
+
+		latch.await(3, TimeUnit.SECONDS);
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void cancelBodyThenPart(String displayName, DefaultPartHttpMessageReader reader) {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("simple.multipart", getClass()), "simple-boundary");
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		StepVerifier.create(result, 1)
+				.consumeNextWith(part -> part.content().subscribe(new CancelSubscriber()))
+				.thenCancel()
+				.verify();
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void firefox(String displayName, DefaultPartHttpMessageReader reader) throws InterruptedException {
+		testBrowser(reader, new ClassPathResource("firefox.multipart", getClass()),
+				"---------------------------18399284482060392383840973206");
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void chrome(String displayName, DefaultPartHttpMessageReader reader) throws InterruptedException {
+		testBrowser(reader, new ClassPathResource("chrome.multipart", getClass()),
+				"----WebKitFormBoundaryEveBLvRT65n21fwU");
+	}
+
+	@ParameterizedDefaultPartHttpMessageReaderTest
+	public void safari(String displayName, DefaultPartHttpMessageReader reader) throws InterruptedException {
+		testBrowser(reader, new ClassPathResource("safari.multipart", getClass()),
+				"----WebKitFormBoundaryG8fJ50opQOML0oGD");
+	}
+
+	@Test
+	public void tooManyParts() throws InterruptedException {
+		MockServerHttpRequest request = createRequest(
+				new ClassPathResource("simple.multipart", getClass()), "simple-boundary");
+
+		DefaultPartHttpMessageReader reader = new DefaultPartHttpMessageReader();
+		reader.setMaxParts(1);
+
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+
+		CountDownLatch latch = new CountDownLatch(1);
+		StepVerifier.create(result)
+				.consumeNextWith(part -> testPart(part, null,
+						"This is implicitly typed plain ASCII text.\r\nIt does NOT end with a linebreak.", latch)).as("Part 1")
+				.expectError(DecodingException.class)
+				.verify();
+
+		latch.await();
+	}
+
+	private void testBrowser(DefaultPartHttpMessageReader reader, Resource resource, String boundary)
+			throws InterruptedException {
+
+		MockServerHttpRequest request = createRequest(resource, boundary);
+
+		Flux<Part> result = reader.read(forClass(Part.class), request, emptyMap());
+		CountDownLatch latch = new CountDownLatch(3);
+		StepVerifier.create(result)
+				.consumeNextWith(part -> testBrowserFormField(part, "text1", "a")).as("text1")
+				.consumeNextWith(part -> testBrowserFormField(part, "text2", "b")).as("text2")
+				.consumeNextWith(part -> testBrowserFile(part, "file1", "a.txt", LOREM_IPSUM, latch)).as("file1")
+				.consumeNextWith(part -> testBrowserFile(part, "file2", "a.txt", LOREM_IPSUM, latch)).as("file2-1")
+				.consumeNextWith(part -> testBrowserFile(part, "file2", "b.txt", MUSPI_MEROL, latch)).as("file2-2")
+				.verifyComplete();
+		latch.await();
+	}
+
+	private MockServerHttpRequest createRequest(Resource resource, String boundary) {
+		Flux<DataBuffer> body = DataBufferUtils
+				.readByteChannel(resource::readableChannel, bufferFactory, BUFFER_SIZE);
+
+		MediaType contentType = new MediaType("multipart", "form-data", singletonMap("boundary", boundary));
+		return MockServerHttpRequest.post("/")
+				.contentType(contentType)
+				.body(body);
+	}
+
+	private void testPart(Part part, @Nullable String expectedName, String expectedContents, CountDownLatch latch) {
+		if (expectedName != null) {
+			assertThat(part.name()).isEqualTo(expectedName);
+		}
+
+		Mono<String> content = DataBufferUtils.join(part.content())
+				.map(buffer -> {
+					byte[] bytes = new byte[buffer.readableByteCount()];
+					buffer.read(bytes);
+					release(buffer);
+					return new String(bytes, UTF_8);
+				});
+
+		content.subscribe(s -> assertThat(s).isEqualTo(expectedContents),
+				throwable -> {
+					throw new AssertionError(throwable.getMessage(), throwable);
+				},
+				latch::countDown);
+	}
+
+
+	private static void testBrowserFormField(Part part, String name, String value) {
+		assertThat(part).isInstanceOf(FormFieldPart.class);
+		assertThat(part.name()).isEqualTo(name);
+		FormFieldPart formField = (FormFieldPart) part;
+		assertThat(formField.value()).isEqualTo(value);
+	}
+
+	private static void testBrowserFile(Part part, String name, String filename, String contents, CountDownLatch latch) {
+		try {
+			assertThat(part).isInstanceOf(FilePart.class);
+			assertThat(part.name()).isEqualTo(name);
+			FilePart filePart = (FilePart) part;
+			assertThat(filePart.filename()).isEqualTo(filename);
+
+			Path tempFile = Files.createTempFile("DefaultMultipartMessageReaderTests", null);
+
+			filePart.transferTo(tempFile)
+					.subscribe(null,
+							throwable -> {
+								throw Exceptions.bubble(throwable);
+							},
+							() -> {
+								try {
+									verifyContents(tempFile, contents);
+								}
+								finally {
+									latch.countDown();
+								}
+
+							});
+		}
+		catch (Exception ex) {
+			throw new AssertionError(ex);
+		}
+	}
+
+	private static void verifyContents(Path tempFile, String contents) {
+		try {
+			String result = String.join("", Files.readAllLines(tempFile));
+			assertThat(result).isEqualTo(contents);
+		}
+		catch (IOException ex) {
+			throw new AssertionError(ex);
+		}
+	}
+
+
+	private static class CancelSubscriber extends BaseSubscriber<DataBuffer> {
+
+		@Override
+		protected void hookOnSubscribe(Subscription subscription) {
+			request(1);
+		}
+
+		@Override
+		protected void hookOnNext(DataBuffer buffer) {
+			DataBufferUtils.release(buffer);
+			cancel();
+		}
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@Target(ElementType.METHOD)
+	@ParameterizedTest(name = "[{index}] {0}")
+	@MethodSource("org.springframework.http.codec.multipart.DefaultPartHttpMessageReaderTests#messageReaders()")
+	public @interface ParameterizedDefaultPartHttpMessageReaderTest {
+	}
+
+	public static Stream<Arguments> messageReaders() {
+		DefaultPartHttpMessageReader streaming = new DefaultPartHttpMessageReader();
+		streaming.setStreaming(true);
+
+		DefaultPartHttpMessageReader inMemory = new DefaultPartHttpMessageReader();
+		inMemory.setStreaming(false);
+		inMemory.setMaxInMemorySize(1000);
+
+		DefaultPartHttpMessageReader onDisk = new DefaultPartHttpMessageReader();
+		onDisk.setStreaming(false);
+		onDisk.setMaxInMemorySize(100);
+
+		return Stream.of(
+				arguments("streaming", streaming),
+				arguments("in-memory", inMemory),
+				arguments("on-disk", onDisk)
+				);
+	}
+
+
+}

spring-web/src/test/java/org/springframework/http/codec/support/ServerCodecConfigurerTests.java

@@ -56,9 +56,9 @@ import org.springframework.http.codec.json.Jackson2JsonDecoder;
 import org.springframework.http.codec.json.Jackson2JsonEncoder;
 import org.springframework.http.codec.json.Jackson2SmileDecoder;
 import org.springframework.http.codec.json.Jackson2SmileEncoder;
+import org.springframework.http.codec.multipart.DefaultPartHttpMessageReader;
 import org.springframework.http.codec.multipart.MultipartHttpMessageReader;
 import org.springframework.http.codec.multipart.PartHttpMessageWriter;
-import org.springframework.http.codec.multipart.SynchronossPartHttpMessageReader;
 import org.springframework.http.codec.protobuf.ProtobufDecoder;
 import org.springframework.http.codec.protobuf.ProtobufHttpMessageWriter;
 import org.springframework.http.codec.xml.Jaxb2XmlDecoder;
@@ -92,7 +92,7 @@ public class ServerCodecConfigurerTests {
 		assertStringDecoder(getNextDecoder(readers), true);
 		assertThat(getNextDecoder(readers).getClass()).isEqualTo(ProtobufDecoder.class);
 		assertThat(readers.get(this.index.getAndIncrement()).getClass()).isEqualTo(FormHttpMessageReader.class);
-		assertThat(readers.get(this.index.getAndIncrement()).getClass()).isEqualTo(SynchronossPartHttpMessageReader.class);
+		assertThat(readers.get(this.index.getAndIncrement()).getClass()).isEqualTo(DefaultPartHttpMessageReader.class);
 		assertThat(readers.get(this.index.getAndIncrement()).getClass()).isEqualTo(MultipartHttpMessageReader.class);
 		assertThat(getNextDecoder(readers).getClass()).isEqualTo(Jackson2JsonDecoder.class);
 		assertThat(getNextDecoder(readers).getClass()).isEqualTo(Jackson2SmileDecoder.class);
@@ -146,10 +146,10 @@ public class ServerCodecConfigurerTests {
 		assertThat(((StringDecoder) getNextDecoder(readers)).getMaxInMemorySize()).isEqualTo(size);
 		assertThat(((ProtobufDecoder) getNextDecoder(readers)).getMaxMessageSize()).isEqualTo(size);
 		assertThat(((FormHttpMessageReader) nextReader(readers)).getMaxInMemorySize()).isEqualTo(size);
-		assertThat(((SynchronossPartHttpMessageReader) nextReader(readers)).getMaxInMemorySize()).isEqualTo(size);
+		assertThat(((DefaultPartHttpMessageReader) nextReader(readers)).getMaxInMemorySize()).isEqualTo(size);
 
 		MultipartHttpMessageReader multipartReader = (MultipartHttpMessageReader) nextReader(readers);
-		SynchronossPartHttpMessageReader reader = (SynchronossPartHttpMessageReader) multipartReader.getPartReader();
+		DefaultPartHttpMessageReader reader = (DefaultPartHttpMessageReader) multipartReader.getPartReader();
 		assertThat((reader).getMaxInMemorySize()).isEqualTo(size);
 
 		assertThat(((Jackson2JsonDecoder) getNextDecoder(readers)).getMaxInMemorySize()).isEqualTo(size);
@@ -190,7 +190,7 @@ public class ServerCodecConfigurerTests {
 		MultipartHttpMessageReader multipartReader = findCodec(readers, MultipartHttpMessageReader.class);
 		assertThat(multipartReader.isEnableLoggingRequestDetails()).isTrue();
 
-		SynchronossPartHttpMessageReader reader = (SynchronossPartHttpMessageReader) multipartReader.getPartReader();
+		DefaultPartHttpMessageReader reader = (DefaultPartHttpMessageReader) multipartReader.getPartReader();
 		assertThat(reader.isEnableLoggingRequestDetails()).isTrue();
 	}
 
@@ -213,7 +213,7 @@ public class ServerCodecConfigurerTests {
 	public void cloneConfigurer() {
 		ServerCodecConfigurer clone = this.configurer.clone();
 
-		MultipartHttpMessageReader reader = new MultipartHttpMessageReader(new SynchronossPartHttpMessageReader());
+		MultipartHttpMessageReader reader = new MultipartHttpMessageReader(new DefaultPartHttpMessageReader());
 		Jackson2JsonEncoder encoder = new Jackson2JsonEncoder();
 		clone.defaultCodecs().multipartReader(reader);
 		clone.defaultCodecs().serverSentEventEncoder(encoder);

spring-web/src/test/resources/org/springframework/http/codec/multipart/files.multipart

@@ -0,0 +1,13 @@
+------WebKitFormBoundaryG8fJ50opQOML0oGD
+Content-Disposition: form-data; name="file2"; filename="a.txt"
+Content-Type: text/plain
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer iaculis metus id vestibulum nullam.
+
+------WebKitFormBoundaryG8fJ50opQOML0oGD
+Content-Disposition: form-data; name="file2"; filename="b.txt"
+Content-Type: text/plain
+
+.mallun mulubitsev di sutem silucai regetnI .tile gnicsipida rutetcesnoc ,tema tis rolod muspi meroL
+
+------WebKitFormBoundaryG8fJ50opQOML0oGD--

spring-web/src/test/resources/org/springframework/http/codec/multipart/no-end-body.multipart

@@ -0,0 +1,4 @@
+--boundary
+Header: Value
+
+a

spring-web/src/test/resources/org/springframework/http/codec/multipart/no-end-boundary.multipart

@@ -0,0 +1,5 @@
+--boundary
+Header: Value
+
+a
+--boundary

spring-web/src/test/resources/org/springframework/http/codec/multipart/no-end-header.multipart

@@ -0,0 +1,6 @@
+--boundary
+Header-1: Value1
+Header-2: Value2
+Header-3: Value3
+Header-4: Value4
+--boundary--

spring-web/src/test/resources/org/springframework/http/codec/multipart/no-header.multipart

@@ -0,0 +1,4 @@
+--boundary
+
+a
+--boundary--

spring-web/src/test/resources/org/springframework/http/codec/multipart/simple.multipart

@@ -0,0 +1,16 @@
+This is the preamble.  It is to be ignored, though it
+is a handy place for mail composers to include an
+explanatory note to non-MIME compliant readers.
+--simple-boundary
+
+This is implicitly typed plain ASCII text.
+It does NOT end with a linebreak.
+--simple-boundary
+Content-type: text/plain; charset=us-ascii
+
+This is explicitly typed plain ASCII text.
+It DOES end with a linebreak.
+
+--simple-boundary--
+This is the epilogue.  It is also to be ignored.
+