session_start() interfering with "zip" header.

[adrianTNT]

Hello.

I have a code that should prompt for a zip file download.

 

header("Content-Type: application/zip");
header('Content-length:'.filesize('zips/'.$_REQUEST['listing_id'].'.zip'));
readfile('blabla.zip');

 

It works OK but the problem is that I have to add session_start() right before that code, to check some user properties.

When I do this I get "corrupted zip file" error in browser.

 

Is it wrong to add session_start() with zip header info? Maybe there is some known issue?

Thank you.

[mapleleaf]

send the user to another page which checks the session data and header on to your zip download.

The answer to your question I do not have but maybe a solution is enough

[adrianTNT]

That was my solution too, I thought there is another way around this.

Otherwise, (as you said) I will have to separate session_start() from the file download.

 

Any other ideas why that would happen ?!

[kenrbnsn]

Can you post more of you code? Just doing a

<?php
session_start();
?>

shouldn't corrupt the file.

 

Ken

[adrianTNT]

Can you post more of you code? ... session_start(); shouldn't corrupt the file.

I simplified it as much as I could removing db queries, this gives an error:

 

if(isset($_REQUEST['file_to_get']) and $_REQUEST['file_to_get']!=''){
session_start();
header("Content-Type: application/zip");
header('Content-length:'.filesize('temp_zips/'.$_REQUEST['file_to_get']));
header("Content-Disposition: attachment; filename=".$_REQUEST['file_to_get']);
readfile('temp_zips/'.$_REQUEST['file_to_get']);
unlink('temp_zips/'.$_REQUEST['file_to_get']);
exit;
}
?>

 

Just adding session_start() there shows me this error:

 

 

Maybe I should add some encoding header information?

[kenrbnsn]

I bet there are error messages you're not seeing.

 

Save the file and try opening it up with a text editor, you will probably see them.

 

Ken

[adrianTNT]

I looked with notepad and first characters appear to be pczip something (the library that creates the zip) but I dont see any errors.

I attached that zip if you want to look but I think there is nothing helpfull.

 

This happens in InternetExplorer only, if I chose directly "open" at download prompt.

If I chose "save" then after download completed I chose "open" it works fine.

 

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