File Download

[D L H]

Hello.

I want to create a gwt application that generates a file and allows
the client to download it. I was planning on generating the file with
a servlet, but how do i allow the client to download it without
navigating away from the application?

-DLH

[georgopoul...@gmail.com]

I use something like this:

String url = GWT.getModuleBaseURL() + "fileDownload?file=" +
URL.decode(path).toString();
Window.open(url, "_self", ""); // or windowName = _blank

Where 'fileDownload' is a servlet. In the HttpServletResponse I put:

response.setContentType("application/octet-stream");
response.setContentLength(Long.valueOf(
mRemoteFileIOService.getFileSize(pUserName, pUserPath,
fileName)).intValue());
response.setHeader("Content-disposition", "attachement; filename=
\""
+ getRealFileName(getFileName(fileName)) + "\";");
response.setHeader("Pragma", "public");
response.setHeader("Cache-Control", "max-age=0");

[Mr. Len Weincier]

Hi

You can do it in a servlet something like this

Regards,
Len

/**
* Allow us to retrieve static content
* Author: <a href="mailto:l...@guruhut.com">Len Weincier</a>
*/
public class DocServlet extends HttpServlet {

public void service(HttpServletRequest request,
HttpServletResponse response) throws IOException {
ServletContext context = getServletContext();

File file = new
File(context.getRealPath(getPath(request.getRequestURI())));

// Return a 404 if we could not find the file
if (!file.exists() || !file.canRead()) {
response.setStatus(HttpServletResponse.SC_NOT_FOUND);
return;
}
response.setContentType(mimeType);
response.setContentLength((int) file.length());

FileInputStream in = new FileInputStream(file);
OutputStream out = response.getOutputStream();

// Copy the contents of the file to the output stream in chunks
byte[] buf = new byte[1024];
int count = 0;
while ((count = in.read(buf)) >= 0) {
out.write(buf, 0, count);
}
in.close();
out.close();

[D L H]

Thanks! It works great.

I only have one more question. The file i'm generating with this
application is an xml-based format that I created specifically for
this application. What mime type would you recommend? i don't want
firefox (or any other browser) to give the option to open the file
with some xml reader.

[Reinier Zwitserloot]

application/xml+foobar

where foobar is something you come up with. And if that doesn't fly,
then you're stuck with just application/xml.

[Reinier Zwitserloot]

uhhh, you DONT want firefox to offer to open it with an external app.
application/octet-stream is what you're looking for.

[Len Weincier]

Hi

Well if its not really xml - i.e. just for your app then you can
create your own Text/MyCustomMimeType for it

Len