PHP File Download using POST data via jQuery AJAX

Question

So I know there have been a number of similar posts, but I think this is enough of a variation to warrant its own question:

I am building an XLS exporter in PHP and

Answer 1

It is possible to POST to a hidden iframe. Therefore, you don't need to worry about the length of the query string; you will post the key/value pairs which will generate your XLS file and subsequently force the file download to the browser.

<form method="post" action="/download/xls" target="download_xls"> 
  <fieldset>
    <label>Key 1:</label>
    <input type="text" name="key_1" />
  </fieldset>

  <fieldset>
    <label>Key 2:</label>
    <input type="text" name="key_2" />
  </fieldset>

    <fieldset>
            <input type="submit" value="Submit" /> 
    </fieldset> 
</form>

<iframe id="download_xls" name="download_xls" width="0" height="0" scrolling="no" frameborder="0"></iframe>

UPDATE A quick Google search turned up this article: http://particletree.com/notebook/ajax-file-download-or-not/

Basically, the suggestion is to POST your form to the current page and respond with a file download. This alternative might be good enough for you.

Answer 2

This seems like it should be pretty simple, but it all depends on where you're putting those XLS files you're generating. If you're intending that the response to the post should be a "Save File" dialog — that is, the file itself — then all you have to do is make sure the "Content-Disposition" header is set to "attachment", and then stream out the file contents.

If you're going to generate the file and keep it around, well you're going to have to store it somewhere with an identifier. In that case, you'd just respond with an ordinary page that's got a "download" link, such that that link includes the file identifier. That can trigger either a GET or a POST, and the server would respond to that pretty much as I described above.

A hidden <iframe> doesn't really figure into this, in my opinion.