Format UTF-8 filenames correctly for download (#16556)

The code is the same for both FileDownloader and DownloadStream except
that FileDownloader forces the content-type to be an "attachment".

Change-Id: I50abf3b0f019b773bc0a44b16536a9479f9f472f

2 files changed, 45 insertions, 13 deletions

diff --git a/server/src/com/vaadin/server/DownloadStream.java b/server/src/com/vaadin/server/DownloadStream.java
index 681c438967..0dfd9e42c3 100644
--- a/server/src/com/vaadin/server/DownloadStream.java
+++ b/server/src/com/vaadin/server/DownloadStream.java
@@ -20,9 +20,12 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.Serializable;
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.logging.Logger;
 
 import javax.servlet.http.HttpServletResponse;
 
@@ -40,6 +43,8 @@ import javax.servlet.http.HttpServletResponse;
 @SuppressWarnings("serial")
 public class DownloadStream implements Serializable {
 
+    public static final String CONTENT_DISPOSITION = "Content-Disposition";
+
     /**
      * Maximum cache time.
      */
@@ -280,17 +285,14 @@ public class DownloadStream implements Serializable {
                     }
                 }
 
-                // suggest local filename from DownloadStream if
-                // Content-Disposition
-                // not explicitly set
-                String contentDispositionValue = getParameter("Content-Disposition");
-                if (contentDispositionValue == null) {
-                    contentDispositionValue = "filename=\"" + getFileName()
-                            + "\"";
-                    response.setHeader("Content-Disposition",
-                            contentDispositionValue);
+                // Content-Disposition: attachment generally forces download
+                String contentDisposition = getParameter(CONTENT_DISPOSITION);
+                if (contentDisposition == null) {
+                    contentDisposition = getContentDispositionFilename(getFileName());
                 }
 
+                response.setHeader(CONTENT_DISPOSITION, contentDisposition);
+
                 int bufferSize = getBufferSize();
                 if (bufferSize <= 0 || bufferSize > Constants.MAX_BUFFER_SIZE) {
                     bufferSize = Constants.DEFAULT_BUFFER_SIZE;
@@ -318,6 +320,30 @@ public class DownloadStream implements Serializable {
     }
 
     /**
+     * Returns the filename formatted for inclusion in a Content-Disposition
+     * header. Includes both a plain version of the name and a UTF-8 version
+     * 
+     * @since
+     * @param filename
+     *            The filename to include
+     * @return A value for inclusion in a Content-Disposition header
+     */
+    public static String getContentDispositionFilename(String filename) {
+        try {
+            String encodedFilename = URLEncoder.encode(filename, "UTF-8");
+            return String.format("filename=\"%s\"; filename*=utf-8''%s",
+                    encodedFilename, encodedFilename);
+        } catch (UnsupportedEncodingException e) {
+            return null;
+        }
+
+    }
+
+    public static Logger getLogger() {
+        return Logger.getLogger(DownloadStream.class.getName());
+    }
+
+    /**
      * Helper method that tries to close an output stream and ignores any
      * exceptions.
      * 
diff --git a/server/src/com/vaadin/server/FileDownloader.java b/server/src/com/vaadin/server/FileDownloader.java
index 42c2f76e1a..b0c3bb1120 100644
--- a/server/src/com/vaadin/server/FileDownloader.java
+++ b/server/src/com/vaadin/server/FileDownloader.java
@@ -141,12 +141,17 @@ public class FileDownloader extends AbstractExtension {
             }
             stream = ((ConnectorResource) resource).getStream();
 
-            if (stream.getParameter("Content-Disposition") == null) {
-                // Content-Disposition: attachment generally forces download
-                stream.setParameter("Content-Disposition",
-                        "attachment; filename=\"" + stream.getFileName() + "\"");
+            String contentDisposition = stream
+                    .getParameter(DownloadStream.CONTENT_DISPOSITION);
+            if (contentDisposition == null) {
+                contentDisposition = "attachment; "
+                        + DownloadStream.getContentDispositionFilename(stream
+                                .getFileName());
             }
 
+            stream.setParameter(DownloadStream.CONTENT_DISPOSITION,
+                    contentDisposition);
+
             // Content-Type to block eager browser plug-ins from hijacking
             // the file
             if (isOverrideContentType()) {
@@ -158,4 +163,5 @@ public class FileDownloader extends AbstractExtension {
         stream.writeResponse(request, response);
         return true;
     }
+
 }