Remove Jakarta Mail dependency from spring-web

This commit removes the dependency that the spring-web module has on
Jakarta Mail.

In FormHttpMessageConverter, a dependency on
jakarta.mail.internet.MimeUtility was replaced by existing encoding
logic in ContentDisposition.

In StandardMultipartHttpServletRequest, a dependency on the same
MimeUtility was replaced by new quoted-printable decoding logic in
ContentDisposition.

Closes gh-28392

spring-web/spring-web.gradle

@@ -15,7 +15,6 @@ dependencies {
 	optional("jakarta.el:jakarta.el-api")
 	optional("jakarta.faces:jakarta.faces-api")
 	optional("jakarta.json.bind:jakarta.json.bind-api")
-	optional("jakarta.mail:jakarta.mail-api")
 	optional("jakarta.validation:jakarta.validation-api")
 	optional("jakarta.xml.bind:jakarta.xml.bind-api")
 	optional("io.reactivex.rxjava3:rxjava")

spring-web/src/main/java/org/springframework/http/ContentDisposition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -33,6 +33,7 @@ import org.springframework.util.ObjectUtils;
 import org.springframework.util.StreamUtils;
 
 import static java.nio.charset.StandardCharsets.ISO_8859_1;
+import static java.nio.charset.StandardCharsets.US_ASCII;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.time.format.DateTimeFormatter.RFC_1123_DATE_TIME;
 
@@ -51,6 +52,9 @@ public final class ContentDisposition {
 	private final static Pattern BASE64_ENCODED_PATTERN =
 			Pattern.compile("=\\?([0-9a-zA-Z-_]+)\\?B\\?([+/0-9a-zA-Z]+=*)\\?=");
 
+	private final static Pattern QUOTED_PRINTABLE_ENCODED_PATTERN =
+			Pattern.compile("=\\?([0-9a-zA-Z-_]+)\\?Q\\?(\\p{Print}+)\\?=");
+
 	private static final String INVALID_HEADER_FIELD_PARAMETER_FORMAT =
 			"Invalid header field parameter format (as defined in RFC 5987)";
 
@@ -371,12 +375,20 @@ public final class ContentDisposition {
 					if (value.startsWith("=?") ) {
 						Matcher matcher = BASE64_ENCODED_PATTERN.matcher(value);
 						if (matcher.find()) {
-							String match1 = matcher.group(1);
-							String match2 = matcher.group(2);
-							filename = new String(Base64.getDecoder().decode(match2), Charset.forName(match1));
+							charset = Charset.forName(matcher.group(1));
+							String encodedValue = matcher.group(2);
+							filename = new String(Base64.getDecoder().decode(encodedValue), charset);
 						}
 						else {
-							filename = value;
+							matcher = QUOTED_PRINTABLE_ENCODED_PATTERN.matcher(value);
+							if (matcher.find()) {
+								charset = Charset.forName(matcher.group(1));
+								String encodedValue = matcher.group(2);
+								filename = decodeQuotedPrintableFilename(encodedValue, charset);
+							}
+							else {
+								filename = value;
+							}
 						}
 					}
 					else {
@@ -498,6 +510,43 @@ public final class ContentDisposition {
 				c == '.' || c == '^' || c == '_' || c == '`' || c == '|' || c == '~';
 	}
 
+	/**
+	 * Decode the given header field param as described in RFC 2047.
+	 * @param filename the filename
+	 * @param charset the charset for the filename
+	 * @return the encoded header field param
+	 * @see <a href="https://tools.ietf.org/html/rfc2047">RFC 2047</a>
+	 */
+	private static String decodeQuotedPrintableFilename(String filename, Charset charset) {
+		Assert.notNull(filename, "'input' String` should not be null");
+		Assert.notNull(charset, "'charset' should not be null");
+
+		byte[] value = filename.getBytes(US_ASCII);
+		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		int index = 0;
+		while (index < value.length) {
+			byte b = value[index];
+			if (b == '_') {
+				baos.write(' ');
+				index++;
+			}
+			else if (b == '=' && index < value.length - 2) {
+				int i1 = Character.digit((char) value[index + 1], 16);
+				int i2 = Character.digit((char) value[index + 2], 16);
+				if (i1 == -1 || i2 == -1) {
+					throw new IllegalArgumentException("Not a valid hex sequence: " + filename.substring(index));
+				}
+				baos.write((i1 << 4) | i2);
+				index += 3;
+			}
+			else {
+				baos.write(b);
+				index++;
+			}
+		}
+		return StreamUtils.copyToString(baos, charset);
+	}
+
 	private static String escapeQuotationsInFilename(String filename) {
 		if (filename.indexOf('"') == -1 && filename.indexOf('\\') == -1) {
 			return filename;

spring-web/src/main/java/org/springframework/http/converter/FormHttpMessageConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -18,7 +18,6 @@ package org.springframework.http.converter;
 
 import java.io.IOException;
 import java.io.OutputStream;
-import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.nio.charset.Charset;
@@ -29,9 +28,8 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
-import jakarta.mail.internet.MimeUtility;
-
 import org.springframework.core.io.Resource;
+import org.springframework.http.ContentDisposition;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpInputMessage;
@@ -526,7 +524,13 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 			if (messageConverter.canWrite(partType, partContentType)) {
 				Charset charset = isFilenameCharsetSet() ? StandardCharsets.US_ASCII : this.charset;
 				HttpOutputMessage multipartMessage = new MultipartHttpOutputMessage(os, charset);
-				multipartMessage.getHeaders().setContentDispositionFormData(name, getFilename(partBody));
+				String filename = getFilename(partBody);
+				ContentDisposition.Builder cd = ContentDisposition.formData()
+						.name(name);
+				if (filename != null) {
+					cd.filename(filename, this.multipartCharset);
+				}
+				multipartMessage.getHeaders().setContentDisposition(cd.build());
 				if (!partHeaders.isEmpty()) {
 					multipartMessage.getHeaders().putAll(partHeaders);
 				}
@@ -568,11 +572,7 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 	@Nullable
 	protected String getFilename(Object part) {
 		if (part instanceof Resource resource) {
-			String filename = resource.getFilename();
-			if (filename != null && this.multipartCharset != null) {
-				filename = MimeDelegate.encode(filename, this.multipartCharset.name());
-			}
-			return filename;
+			return resource.getFilename();
 		}
 		else {
 			return null;
@@ -655,20 +655,4 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 		}
 	}
 
-
-	/**
-	 * Inner class to avoid a hard dependency on the JavaMail API.
-	 */
-	private static class MimeDelegate {
-
-		public static String encode(String value, String charset) {
-			try {
-				return MimeUtility.encodeText(value, charset, null);
-			}
-			catch (UnsupportedEncodingException ex) {
-				throw new IllegalStateException(ex);
-			}
-		}
-	}
-
 }

spring-web/src/main/java/org/springframework/web/multipart/support/StandardMultipartHttpServletRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -20,7 +20,6 @@ import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.Serializable;
-import java.io.UnsupportedEncodingException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -32,7 +31,6 @@ import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
 
-import jakarta.mail.internet.MimeUtility;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.Part;
 
@@ -100,9 +98,6 @@ public class StandardMultipartHttpServletRequest extends AbstractMultipartHttpSe
 				ContentDisposition disposition = ContentDisposition.parse(headerValue);
 				String filename = disposition.getFilename();
 				if (filename != null) {
-					if (filename.startsWith("=?") && filename.endsWith("?=")) {
-						filename = MimeDelegate.decode(filename);
-					}
 					files.add(part.getName(), new StandardMultipartFile(part, filename));
 				}
 				else {
@@ -271,20 +266,4 @@ public class StandardMultipartHttpServletRequest extends AbstractMultipartHttpSe
 		}
 	}
 
-
-	/**
-	 * Inner class to avoid a hard dependency on the JavaMail API.
-	 */
-	private static class MimeDelegate {
-
-		public static String decode(String value) {
-			try {
-				return MimeUtility.decodeText(value);
-			}
-			catch (UnsupportedEncodingException ex) {
-				throw new IllegalStateException(ex);
-			}
-		}
-	}
-
 }

spring-web/src/test/java/org/springframework/http/ContentDispositionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -92,6 +92,18 @@ class ContentDispositionTests {
 		assertThat(parse(input).getFilename()).isEqualTo("日本語.csv");
 	}
 
+	@Test
+	void parseQuotedPrintableFilename() {
+		String input = "attachment; filename=\"=?UTF-8?Q?=E6=97=A5=E6=9C=AC=E8=AA=9E.csv?=\"";
+		assertThat(parse(input).getFilename()).isEqualTo("日本語.csv");
+	}
+
+	@Test
+	void parseQuotedPrintableShiftJISFilename() {
+		String input = "attachment; filename=\"=?SHIFT_JIS?Q?=93=FA=96{=8C=EA.csv?=\"";
+		assertThat(parse(input).getFilename()).isEqualTo("日本語.csv");
+	}
+
 	@Test
 	void parseEncodedFilenameWithoutCharset() {
 		assertThat(parse("form-data; name=\"name\"; filename*=test.txt"))