Comments on: Ajax File Download … Or Not

By: mike

mike — Sat, 13 Oct 2007 00:53:09 +0000

We try to use ajax file uploads, but now we write plugins for browsers. Why? I think, (first) ajax upload now is not an transparent technology and (second) we have requirements for restore upload process after crash. ps: we try to use flash uploaders, but it seems also non-stable and raw…

By: Ryan Campbell

Ryan Campbell — Thu, 11 Oct 2007 14:54:44 +0000

The conditions for the file are dynamic, so the hidden variable is always changing. I guess a similar example would be those JavaScript libraries that let you build in which functionality you would like before downloading.

By: Kai

Kai — Thu, 11 Oct 2007 14:15:05 +0000

Well, could’t you achieve the same effect with just plain HTML and no Javascript at all? Why do you need the Javascript in this example?

By: random8r

random8r — Thu, 11 Oct 2007 07:50:59 +0000

Yeah, you were pretty silly. It’s also fairly common to think that way. It comes about because you’re thinking AJAX is “doing something without updating the screen”, but AJAX is not that. AJAX is “get the server to give me a response as Javascript and execute it”.

You didn’t want Javascript, you wanted a file as a response.

You need to adjust your thinking to be more precise! :-)

By the way, here’s your hug: [[hug]].

By: Hemebond

Hemebond — Tue, 09 Oct 2007 12:21:59 +0000

Erg. I just re-read your second code block. It is just a regular form except it uses Javascript to set variables that would/should be set using form elements. I thought you were doing something with AJAX to get the download.

By: Hemebond

Hemebond — Tue, 09 Oct 2007 12:18:31 +0000

If your download doesn’t exist, is it not better that the user see the 404 rather than having a form that silently fails to do anything?

By: Ryan Campbell

Ryan Campbell — Tue, 09 Oct 2007 11:29:04 +0000

If you get a 404 or some other error, the user will leave the page. A way around that is to set the target of the form to a new window.

By: Hemebond

Hemebond — Tue, 09 Oct 2007 10:22:26 +0000

So what happened when you let the user submit a POST form, which returns nothing, and redirected to the download? What does the browser do?

By: hypotheek

hypotheek — Mon, 08 Oct 2007 23:11:12 +0000

Thanks for the easy and clearly described post. Im going to try it right away

By: Ryan Campbell

Ryan Campbell — Mon, 08 Oct 2007 16:48:42 +0000

If the conditions are detailed, they can get quite long. And since the max URL length for IE is ~2000, there are some situations where a POST is needed. In my case, the users are allowed to supply an infinite amount of conditions when “building” their file.