StandardMultipartFile.transferTo falls back to manual copy

Issue: SPR-15257

Author: jhoeller

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -27,7 +27,7 @@
  *
  * <p>The file contents are either stored in memory or temporarily on disk.
  * In either case, the user is responsible for copying file contents to a
- * session-level or persistent store as and if desired. The temporary storages
+ * session-level or persistent store as and if desired. The temporary storage
  * will be cleared at the end of request processing.
  *
  * @author Juergen Hoeller
@@ -50,6 +50,8 @@ public interface MultipartFile extends InputStreamSource {
 	 * 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
+	 * @see org.apache.commons.fileupload.FileItem#getName()
+	 * @see org.springframework.web.multipart.commons.CommonsMultipartFile#setPreserveFilename
 	 */
 	String getOriginalFilename();
 
@@ -81,7 +83,7 @@ public interface MultipartFile extends InputStreamSource {
 
 	/**
 	 * Return an InputStream to read the contents of the file from.
-	 * The user is responsible for closing the stream.
+	 * <p>The user is responsible for closing the returned stream.
 	 * @return the contents of the file as stream, or an empty stream if empty
 	 * @throws IOException in case of access errors (if the temporary store fails)
 	 */
@@ -91,18 +93,22 @@ public interface MultipartFile extends InputStreamSource {
 	/**
 	 * Transfer the received file to the given destination file.
 	 * <p>This may either move the file in the filesystem, copy the file in the
-	 * filesystem, or save memory-held contents to the destination file.
-	 * If the destination file already exists, it will be deleted first.
-	 * <p>If the file has been moved in the filesystem, this operation cannot
-	 * be invoked again. Therefore, call this method just once to be able to
-	 * work with any storage mechanism.
-	 * <p><strong>Note:</strong> when using Servlet 3.0 multipart support you
-	 * need to configure the location relative to which files will be copied
-	 * as explained in {@link javax.servlet.http.Part#write}.
-	 * @param dest the destination file
+	 * filesystem, or save memory-held contents to the destination file. If the
+	 * destination file already exists, it will be deleted first.
+	 * <p>If the target file has been moved in the filesystem, this operation
+	 * cannot be invoked again afterwards. Therefore, call this method just once
+	 * in order to work with any storage mechanism.
+	 * <p><b>NOTE:</b> Depending on the underlying provider, temporary storage
+	 * may be container-dependent, including the base directory for relative
+	 * destinations specified here (e.g. with Servlet 3.0 multipart handling).
+	 * For absolute destinations, the target file may get renamed/moved from its
+	 * temporary location or newly copied, even if a temporary copy already exists.
+	 * @param dest the destination file (typically absolute)
 	 * @throws IOException in case of reading or writing errors
 	 * @throws IllegalStateException if the file has already been moved
 	 * in the filesystem and is not available anymore for another transfer
+	 * @see org.apache.commons.fileupload.FileItem#write(File)
+	 * @see javax.servlet.http.Part#write(String)
 	 */
 	void transferTo(File dest) throws IOException, IllegalStateException;
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * 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.
@@ -165,22 +165,26 @@ public void transferTo(File dest) throws IOException, IllegalStateException {
 			if (logger.isDebugEnabled()) {
 				String action = "transferred";
 				if (!this.fileItem.isInMemory()) {
-					action = isAvailable() ? "copied" : "moved";
+					action = (isAvailable() ? "copied" : "moved");
 				}
 				logger.debug("Multipart file '" + getName() + "' with original filename [" +
 						getOriginalFilename() + "], stored " + getStorageDescription() + ": " +
 						action + " to [" + dest.getAbsolutePath() + "]");
 			}
 		}
 		catch (FileUploadException ex) {
-			throw new IllegalStateException(ex.getMessage());
+			throw new IllegalStateException(ex.getMessage(), ex);
+		}
+		catch (IllegalStateException ex) {
+			// Pass through when coming from FileItem directly
+			throw ex;
 		}
 		catch (IOException ex) {
+			// From I/O operations within FileItem.write
 			throw ex;
 		}
 		catch (Exception ex) {
-			logger.error("Could not transfer to file", ex);
-			throw new IOException("Could not transfer to file: " + ex.getMessage());
+			throw new IOException("File transfer failed", ex);
 		}
 	}
 

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

@@ -17,6 +17,7 @@
 package org.springframework.web.multipart.support;
 
 import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.Serializable;
@@ -307,6 +308,15 @@ public InputStream getInputStream() throws IOException {
 		@Override
 		public void transferTo(File dest) throws IOException, IllegalStateException {
 			this.part.write(dest.getPath());
+			if (dest.isAbsolute() && !dest.exists()) {
+				// Servlet 3.0 Part.write is not guaranteed to support absolute file paths:
+				// may translate the given path to a relative location within a temp dir
+				// (e.g. on Jetty whereas Tomcat and Undertow detect absolute paths).
+				// At least we offloaded the file from memory storage; it'll get deleted
+				// from the temp dir eventually in any case. And for our user's purposes,
+				// we can manually copy it to the requested location as a fallback.
+				FileCopyUtils.copy(this.part.getInputStream(), new FileOutputStream(dest));
+			}
 		}
 	}