CommonsMultipartFile.getOriginalFilename() can be configured to preserve header-specified filename as-is

Issue: SPR-14613
(cherry picked from commit aa29495)

Author: jhoeller

spring-web/src/main/java/org/springframework/web/multipart/MultipartFile.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -48,9 +48,8 @@ public interface MultipartFile extends InputStreamSource {
 	 * Return the original filename in the client's filesystem.
 	 * <p>This may contain path information depending on the browser used,
 	 * but it typically will not with any other than Opera.
-	 * @return the original filename, or the empty String if no file
-	 * has been chosen in the multipart form, or {@code null}
-	 * if not defined or not available
+	 * @return the original filename, or the empty String if no file has been chosen
+	 * in the multipart form, or {@code null} if not defined or not available
 	 */
 	String getOriginalFilename();
 

spring-web/src/main/java/org/springframework/web/multipart/commons/CommonsFileUploadSupport.java

@@ -68,6 +68,8 @@ public abstract class CommonsFileUploadSupport {
 
 	private boolean uploadTempDirSpecified = false;
 
+	private boolean preserveFilename = false;
+
 
 	/**
 	 * Instantiate a new CommonsFileUploadSupport with its
@@ -174,6 +176,20 @@ protected boolean isUploadTempDirSpecified() {
 		return this.uploadTempDirSpecified;
 	}
 
+	/**
+	 * Set whether to preserve the filename as sent by the client, not stripping off
+	 * path information in {@link CommonsMultipartFile#getOriginalFilename()}.
+	 * <p>Default is "false", stripping off path information that may prefix the
+	 * actual filename e.g. from Opera. Switch this to "true" for preserving the
+	 * client-specified filename as-is, including potential path separators.
+	 * @since 4.3.5
+	 * @see MultipartFile#getOriginalFilename()
+	 * @see CommonsMultipartFile#setPreserveFilename(boolean)
+	 */
+	public void setPreserveFilename(boolean preserveFilename) {
+		this.preserveFilename = preserveFilename;
+	}
+
 
 	/**
 	 * Factory method for a Commons DiskFileItemFactory instance.
@@ -265,7 +281,7 @@ protected MultipartParsingResult parseFileItems(List<FileItem> fileItems, String
 			}
 			else {
 				// multipart file field
-				CommonsMultipartFile file = new CommonsMultipartFile(fileItem);
+				CommonsMultipartFile file = createMultipartFile(fileItem);
 				multipartFiles.add(file.getName(), file);
 				if (logger.isDebugEnabled()) {
 					logger.debug("Found multipart file [" + file.getName() + "] of size " + file.getSize() +
@@ -277,6 +293,20 @@ protected MultipartParsingResult parseFileItems(List<FileItem> fileItems, String
 		return new MultipartParsingResult(multipartFiles, multipartParameters, multipartParameterContentTypes);
 	}
 
+	/**
+	 * Create a {@link CommonsMultipartFile} wrapper for the given Commons {@link FileItem}.
+	 * @param fileItem the Commons FileItem to wrap
+	 * @return the corresponding CommonsMultipartFile (potentially a custom subclass)
+	 * @since 4.3.5
+	 * @see #setPreserveFilename(boolean)
+	 * @see CommonsMultipartFile#setPreserveFilename(boolean)
+	 */
+	protected CommonsMultipartFile createMultipartFile(FileItem fileItem) {
+		CommonsMultipartFile multipartFile = new CommonsMultipartFile(fileItem);
+		multipartFile.setPreserveFilename(this.preserveFilename);
+		return multipartFile;
+	}
+
 	/**
 	 * Cleanup the Spring MultipartFiles created during multipart parsing,
 	 * potentially holding temporary data on disk.
@@ -323,6 +353,7 @@ protected static class MultipartParsingResult {
 
 		public MultipartParsingResult(MultiValueMap<String, MultipartFile> mpFiles,
 				Map<String, String[]> mpParams, Map<String, String> mpParamContentTypes) {
+
 			this.multipartFiles = mpFiles;
 			this.multipartParameters = mpParams;
 			this.multipartParameterContentTypes = mpParamContentTypes;

spring-web/src/main/java/org/springframework/web/multipart/commons/CommonsMultipartFile.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -47,6 +47,8 @@ public class CommonsMultipartFile implements MultipartFile, Serializable {
 
 	private final long size;
 
+	private boolean preserveFilename = false;
+
 
 	/**
 	 * Create an instance wrapping the given FileItem.
@@ -66,6 +68,21 @@ public final FileItem getFileItem() {
 		return this.fileItem;
 	}
 
+	/**
+	 * Set whether to preserve the filename as sent by the client, not stripping off
+	 * path information in {@link CommonsMultipartFile#getOriginalFilename()}.
+	 * <p>Default is "false", stripping off path information that may prefix the
+	 * actual filename e.g. from Opera. Switch this to "true" for preserving the
+	 * client-specified filename as-is, including potential path separators.
+	 * @since 4.3.5
+	 * @see #getOriginalFilename()
+	 * @see CommonsMultipartResolver#setPreserveFilename(boolean)
+	 */
+	public void setPreserveFilename(boolean preserveFilename) {
+		this.preserveFilename = preserveFilename;
+	}
+
+
 	@Override
 	public String getName() {
 		return this.fileItem.getFieldName();
@@ -78,6 +95,10 @@ public String getOriginalFilename() {
 			// Should never happen.
 			return "";
 		}
+		if (this.preserveFilename) {
+			// Do not try to strip off a path...
+			return filename;
+		}
 
 		// Check for Unix-style path
 		int unixSep = filename.lastIndexOf("/");