Merge pull request #4542 from IQSS/4524-s3-redirects-utf8-filenames

4524 s3 redirects utf8 filenames

src/main/java/edu/harvard/iq/dataverse/dataaccess/S3AccessIO.java

@@ -39,6 +39,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URL;
+import java.net.URLEncoder;
 import java.nio.channels.Channel;
 import java.nio.channels.Channels;
 import java.nio.channels.WritableByteChannel;
@@ -650,7 +651,19 @@ public String generateTemporaryS3Url() throws IOException {
             generatePresignedUrlRequest.setMethod(HttpMethod.GET); // Default.
             generatePresignedUrlRequest.setExpiration(expiration);
             ResponseHeaderOverrides responseHeaders = new ResponseHeaderOverrides();
-            responseHeaders.setContentDisposition("attachment; filename="+this.getDataFile().getDisplayName());
+            //responseHeaders.setContentDisposition("attachment; filename="+this.getDataFile().getDisplayName());
+            // Encode the file name explicitly specifying the encoding as UTF-8:
+            // (otherwise S3 may not like non-ASCII characters!)
+            // Most browsers are happy with just "filename="+URLEncoder.encode(this.getDataFile().getDisplayName(), "UTF-8") 
+            // in the header. But Firefox appears to require that "UTF8" is 
+            // specified explicitly, as below:
+            responseHeaders.setContentDisposition("attachment; filename*=UTF-8''"+URLEncoder.encode(this.getDataFile().getDisplayName(), "UTF-8"));
+            // - without it, download will work, but Firefox will leave the special
+            // characters in the file name encoded. For example, the file name 
+            // will look like "1976%E2%80%932016.txt" instead of "1976–2016.txt", 
+            // where the dash is the "long dash", represented by a 3-byte UTF8 
+            // character "\xE2\x80\x93"
+
             responseHeaders.setContentType(this.getDataFile().getContentType());
             generatePresignedUrlRequest.setResponseHeaders(responseHeaders);