Retrieve filename from http download file

Question

I am trying to download a file from a webserver and save it under the original filename the server is sending with the file. Downloading works very well, but I am not able to get the real filename.

For real example I am trying to download this file (Foxit PDF Reader).

If I am using this link in a browser like Chrome the browser downloads the file with a exact name including version etc. Where do I get this name from? I tried reading the header informations and was searching for Content-Disposition but the server doesn't send this information. Where do I get the exact filename from?

I tried something like this:

try {            
  URL webfile = new URL("http://www.foxitsoftware.com/downloads/latest.php?product=Foxit-Reader");
  URLConnection con = webfile.openConnection();
  Map map = con.getHeaderFields();
  Set set = map.entrySet();
  Iterator iterator = set.iterator();
  while (iterator.hasNext()) {
      System.out.println(iterator.next());
  }
} catch (IOException ex) {
  System.out.println("Error: "+ex.getMessage());
}

As you can see in the output there is no Content-Disposition:

null=[HTTP/1.1 200 OK]
ETag=["244005-f36d40-4d003f3868000"]
Date=[Sat, 08 Dec 2012 12:29:02 GMT]
Content-Length=[15953216]
Last-Modified=[Tue, 04 Dec 2012 10:01:36 GMT]
Content-Type=[application/x-msdos-program]
Connection=[close]
Accept-Ranges=[bytes]
Server=[Apache/2.2.16 (Debian)]

So how can I retrieve the exact filename? The link in a browser downloads a file with the name FoxitReader544.11281_enu_Setup.exe.

Any ideas?!

score 3 · Accepted Answer · answered Dec 08 '12 at 12:52

3

GET /downloads/latest.php?product=Foxit-Reader HTTP/1.1

gives a response of HTTP/1.1 302 Found

and sets the response header

Location: http://cdn04.foxitsoftware.com/pub/foxit/reader/desktop/win/5.x/5.4/enu/FoxitReader544.11281_enu_Setup.exe

and finally, you issue,

GET /pub/foxit/reader/desktop/win/5.x/5.4/enu/FoxitReader544.11281_enu_Setup.exe HTTP/1.1

That is where the filename seems to be coming from. So, if the redirection is happening transparently, you could still probably get the filename from the request parameter.

answered Dec 08 '12 at 12:52

Anirudh Ramanathan

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Wow! I guessed the GET was Ok because of the `HTTP/1.1 200 OK` Information?! Why did I get a 200 if I should get a 302?! – Marco Dec 08 '12 at 12:56
3

It follows redirects automatically, if the parameter is set. See [**`getFollowRedirects()`**](http://docs.oracle.com/javase/1.5.0/docs/api/java/net/HttpURLConnection.html#getFollowRedirects()) and [**`setFollowRedirects()`**](http://docs.oracle.com/javase/1.5.0/docs/api/java/net/HttpURLConnection.html#setFollowRedirects(boolean)) – Anirudh Ramanathan Dec 08 '12 at 12:59
Nice! Thank you very much! Need to wait 2 more mins to accept... ;) – Marco Dec 08 '12 at 13:01

score 2 · Answer 2 · answered Dec 08 '12 at 12:54

When you request the URL above, the server is responding with a 302 redirection to (header key: Location): http://cdn04.foxitsoftware.com/pub/foxit/reader/desktop/win/5.x/5.4/enu/FoxitReader544.11281_enu_Setup.exe and FoxitReader544.11281_enu_Setup.exe is the file name that gets saved to my computer when I click the original link.

Retrieve filename from http download file

2 Answers2