Download file using wpg_docload doesn't work

Question

Hello All,
I am creating a web page that uploads and downloads files. Oracle table that stores BLOB content and type is working fine.
Upload works fine. When I download file, it opens in the same browser and same tab instead of opening in 'Save As' dialog box . The code is as below:
IF params('submit') ='Download' THEN
SELECT mime_type, dbms_lob.getlength( blob_content ), blob_content
INTO s_mime_type, n_length, lob_cont
FROM rowan.FILE_UPLOAD
WHERE name=params('txtFilename');
-- Set the size so the browser knows how much it will be downloading.
owa_util.mime_header('text/plain', FALSE );
htp.p( 'Content-Length:' || n_length );
-- The filename will be used by the browser if the users does a "Save as"
htp.p('Content-Disposition: attachment; filename="'||params('submit')||'"');
owa_util.http_header_close;
-- Download the BLOB
wpg_docload.download_file( lob_cont );
--htp.showpage ();
END IF;
Thanks,
Himadri.

Answer 1

Your SQL select statement includes the column mime_type.
The HTTP header that is created by your code, sets the Mime type as follows:
owa_util.mime_header('text/plain', FALSE );
So.. the file could be binary, could be an image - and this code tells the browser that the data in that HTTP response is in fact plain ASCII text.
Obviously the browser will choke on that HTTP response as the content is not ASCII text. And it will use the application that is associated with Mime type text/plain to receive that response. By default, that is the browser itself. So it will open a new rendering window/tab (or use the existing one) to display this "text" contents that is expects to receive.
Change that statement in your code to:
owa_util.mime_header(s_mime_type, FALSE );