Forcing the downloading of a file

[Rogue Chameleon]

Hi all

I apologize for the vagueness of the subject line... but it's the best that
I could do. Here is what I am trying to accomplish:

Our users will be receiving automated emails from a web server that will
contain an encrypted file attachment. The file has been encrypted with a
public key. For the file to be useful, it will obviously need to be
decrypted.

What I'd like to do is have a web servlet do the encryption for the users.
Once they get the email, they detach the file, and upload it to the servlet
(using <input type="file">), the decryption will occur. Immediately after
the decryption, I want to "force" the file back to the user. That is, I
want them to be immediately presented with the "download file" dialog box.

Can this be done? If so.... how?

 

[Michael Borgwardt]

Our users will be receiving automated emails from a web server that will
contain an encrypted file attachment. The file has been encrypted with a
public key. For the file to be useful, it will obviously need to be
decrypted.

What I'd like to do is have a web servlet do the encryption for the users.
Once they get the email, they detach the file, and upload it to the servlet
(using <input type="file">), the decryption will occur.

Using HTTPS, I hope. Otherwise it's rather pointless to encrypt the file
in the first place. And where is the passphrase going to be entered?

But if they're going to decrypt it that way anyway, why not just send them
a link and deliver the file directly via the servlet?

Immediately after
the decryption, I want to "force" the file back to the user. That is, I
want them to be immediately presented with the "download file" dialog box.

Can this be done? If so.... how?

Just have the servlet declare the a MIME type of application/octet-stream
for its response and send the file.

 

[Lee]

Immediately after

the decryption, I want to "force" the file back to the user. That is, I
want them to be immediately presented with the "download file" dialog box.

Can this be done? If so.... how?

response.sendRedirect("http://server.com/thedecryptedfile");

 

[Rogue Chameleon]

Just have the servlet declare the a MIME type of application/octet-stream
for its response and send the file.

Send the file.... how? If I have the file within a File object, should I
just send it out in a ServletOutputStream?

 

[Rogue Chameleon]

Just have the servlet declare the a MIME type of application/octet-stream
for its response and send the file.

Send the file.... how? If I have the file within a File object, should I
just send it out in a ServletOutputStream?

 

[Tor Iver Wilhelmsen]

Send the file.... how? If I have the file within a File object, should I
just send it out in a ServletOutputStream?

No, you need to read the contents and send that.

 

[Michael Borgwardt]

response.sendRedirect("http://server.com/thedecryptedfile");

If you do that (send the file unencrypted over HTTP) you needn't have bothered
encrypting it in the first place...