HTML code to use to save a downloaded file with an other name that the URL

jlinkels · 06-12-2007, 01:54 PM

Hi All,

On a web page I have a link to a file. This file is a temporary file with a unique random file name, like mr_station_2ckAZW.csv.

The idea is that when the user clicks on this file name he is presented the usual dialog "open or save the file"

Now when he chooses to save the file, he must edit the file name to something which is sensible, like mr_station_july_2007.csv.

In my PHP script I do know this file name which the user is most likely to use, but on the other hand I am stuck with the real name of the file.

The reason for that is that when the user enters the page, the PHP script generates the CSV file, and stores it as a temporary file. I cannot use a single filename because every user entering this page will generate it. If I use the same file name, the file can be overwritten while it is viewed by someone else etc. Neither can I assign a sensible name to the file like : july_2007, because there are an infinite number of options to generate the file. I cannot allow that user2 downloads the file which was just generated by user1 etc.

Summarizing, if I have a file XXX.CSV and the downloads it, can the default filename to save it be YYY.CSV?

I use Apache, PHP and Javascript. Since it is just "nice to have" I don't want to add another requirement to the enveronment like Java or so.

jlinkels

Guttorm · 06-13-2007, 08:24 AM

Hi

I think you can't do that with HTML, but PHP can do it:

PHP Code:



<?php 
header("Content-Type: text/plain"); 
header("Content-Disposition: attachment; filename=\"yadayada.txt\""); 
echo "Yada\nYada\n"; 
?>

The name of the PHP script doesn't matter to the client - it will be "yadayada.txt".

Hope this helps.

jlinkels · 06-13-2007, 09:36 AM

Man!

This is EXACTLY what I needed! It also solves my next problem: "How To Generate A PDF Document On Demand After Clicking On A Link And Download It Without Leaving The Page"

I had seen the header function in PHP but I never comprehended that it should be used in this way.

Thanks a lot!

jlinkels

jlinkels · 06-21-2007, 07:28 PM

An important addition to this.

I did exactly as Guttorm pointed out. It worked like a charm for CSV files in both Opera and IE.

Then I continued with the project and tried to download a dynamically generated PDF file. Saving or opening in Opera was no problem again, but in IE I could only save. Trying to open would download the file all right, but Acroread does not open te file and gives an error message "file not found".

I copied this piece of code from the PHP manual:

Code:

<?php
$mm_type="application/octet-stream";

header("Cache-Control: public, must-revalidate");
header("Pragma: hack");
header("Content-Type: " . $mm_type);
header("Content-Length: " .(string)(filesize($url)) );
header('Content-Disposition: attachment; filename="'.basename($url).'"');
header("Content-Transfer-Encoding: binary\n");
                   
$fp = fopen($url, 'rb');
$buffer = fread($fp, filesize($url));
fclose ($fp);
                   
print $buffer;
?>

(The code is on the manual page of the "header" function on php.net and posted by rich at pioneering-principles dot co dot uk.)

Now don't ask me which line exactly causes the opening to work. I was in a hurry (who isn't?) and I was happy enough to have it working.

Opening the file in IE 6 works now, and it still works in Opera.

jlinkels

Edit: PS how do you guys get that nicely colored PHP syntax posted here?

jlinkels · 06-21-2007, 07:40 PM

One more thing:

The call to the header function header should generate the very first output of a web page. Even a <html> tag or a space is not allowed.

This is especially tricky when you include some other PHP files. They might output some innocent code which you do not normally see on a web page (like <strong></strong>)

The recommended method for avoiding this is to call this function:

Code:

<?
ob_start();
--- blah blah blah and other output ---
ob_end_flush();
header("Content-Type: text/plain"); 
header("Content-Disposition: attachment; filename=\"yadayada.txt\"");
?>

Now the problem her is that when you call ob_end_flush, everything which was nicely buffered is sent to your browser and picked up by the save function.

So instead of the wanted file, you receive all that buffered output that you didn't want in the first place! It really screws up the downloaded file.

So it is essential that you do:

Code:

ob_start();
--- blah blah blah and other output ---
ob_end_clean();
ob_end_flush();

to clean the buffer before you start sending downloaded files!

jlinkels