php header() function problem about download file - php

I have a file download function in my website. it works fine before. but after we moved the site to another server with runs PHP 5 (it runs on PHP 4 before). when click to download, it automatically adds a extra blank line at the beginning and the end of the file which we don't want to. Here is the code for downloading function:
header("Content-Type: application/gas");
header("Cache-control: private");
header("Content-Disposition: attachment; filename=aaa.gas");
Could anyone please help me out? Thanks!

There may be an extra blank line after the ?> that closes the PHP within the script. Exit the script after sending the file in order to prevent this from mattering.

Related

can download file in localhost but not server

Anyone face this problem before?
like i implement a backup php script.
when i click the button download.
the file will auto download and store in my localhost folder.
but when i upload the script to server and try to run, the script can run and display the successful message. but no any file download.
//SAVE THE BACKUP AS SQL FILE
$handle = fopen($DbName.'-Database-Backup-'.$table.date('Y-m-d #h-i-s').'.sql','w+');
fwrite($handle,$data);
fclose($handle);
below is the script that i wrote.
Php script
Try using the following header in php.
Example:
header('Content-disposition: attachment; filename=my.sql');
header('Content-type: text/plain');

Generated xml file is harmful for computer?

I did an xml file and force download it by these headers:
header('Content-disposition: attachment; filename="export.xml"');
header('Content-type: application/xml; charset=utf8');
readfile('export.xml');
But before the download I see a dialog that this file can be harmful for my computer? How to get rid of this dialog? Maybe my headers is wrong?
upd Well, can do nothing, I did a test on my test-hosting, u can check it here: site with generation link, and an xml file as is: export.xml
Try changing application/xml to text/xml. Probably your browser thinks that application means executable.
Try this :
<?php
header('Content-disposition: attachment; filename="export.xml"');
header('Content-type: "text/xml"; charset="utf8"');
readfile('export.xml');
?>
Note: This does not solve your issue, however it did solve an issue I had on my computer giving that notice (windows, chrome, apache webserver, PHP 5.4.10). I leave it here for future visitors.
Some browsers do not only look for the headers but also for the "filename" in the URL.
For example if you download a PHP file that contains XML, the browser might identify it as a dangerous file (because it can be executed on your system or is not within some whitelist or what not):
http://example.com/xml-download.php
A simple solution is to make this file not end with .php any longer, for example by adding a ?:
http://example.com/xml-download.php?
And continue with that to even signal the filename that way:
http://example.com/xml-download.php?export.xml
(the last one is not necessary but can be useful especially with some older browsers)

Why downloaded file is not downloaded instead it is shown in browser?

I redirect the visitors in my website from page A to page B. In page B I expect users to get the downloaded PDF file (to be downloaded when page B is loading).
I have taken the code from another article (see a previous question answered here) and my code of page B is the following:
<?php
header('Content-Disposition: attachment; filename=nature.pdf');
header('Content-type: application/pdf');
$fn=fopen("/wp-content/nature.pdf","r");
fpassthru($fn);
?>
The output is not by opening a download dialog box, instead some unreadable characters are displayed in browser such as the following (I have just picked up a small sample below):
%PDF-1.4 %���� 3 0 obj <>stream x���MK1�o�+�$zIg&�� V=T�=Xo����K��i+#V�yx3��඀(BX�pW`
Server: OS Linux; PHP version: 5.2.17
The visitor -> Browser: Firefox; OS: Windows 2000
Is it possible to fail due to the old OS on client side? If not, does anybody know a solution how to force the download? Any help would be highly appreciated.
Thanks.
Try it with the Content-Length header:
ob_clean(); ob_start();
header('Content-Disposition: attachment; filename=nature.pdf');
header('Content-type: application/pdf');
header ("Content-Length: ".filesize("/wp-content/nature.pdf"));
readfile("/wp-content/nature.pdf");
exit;
There was a quirk in the really old browsers when Content-disposition was first being introduced, some of the really old browsers wouldn't show the "Save As" dialogue unless it couldn't recognize the type of file you were trying to open. Try setting the Content-type to nothing (or something unrecognizable), and see if that'll force the older browser to pop the save-as dialogue.
header('Content-type: ');
If that works, then I'd suggest adding in a line of PHP to detect whether or not they're on an old browser before running that line, as modern browsers will use that header to determine what program the file should be opened with.

simultaneously download on server and on user

I am currently developing an application in PHP in which my server (a dedicated server) must to download a file, and the user should download the file in same time.
Here is an example :
Server start to download a file at a time A.
User wants to download this file at the time A + 3 seconds (for example)
I already solved the problem :"If the user downloads the file faster than the server..". But I didn't know how to make a php script in which the user is gonna to download the full file (it means that the size must be the full size of the file, not the size it's currently downloaded at the time A+3seconds). I already make that :
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.$data['name'].'";');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.$data['size']);
readfile($remoteFile);
But it doesn't work, the user is gonna download just the size it is currently on the server (which corrupt the file) and not the full file...
If you have any solution, thank you.
You could probably pipe the file manually, by opening the connection and reading until you're past all headers. Then once you've figured out the Content-Length, send that to the user and just echo all remaining data you get (do use flush() and avoid output buffers).
Pseudocode(-ish):
open the file
# grab headers
while you didn't get all HTTP headers:
read more
look for the Content-Length header
send the Content-Length header
# grab the file
while the rest of the request isn't done
read more
send it to the user
flush the buffers
done
Expanding on #Tom answer, you can use cURL to greatly simplify the algorithm by using the CURLOPT_HEADERFUNCTION and CURLOPT_READFUNCTION callbacks - see curl_setopt().
Don't send the content-length header. It's not required assuming you're using http 1.1(your webserver almost certainly does). Drawback is their browser cant show download time/size remaining.

PHP Headers and downloads

I am currently trying to develop a PHP application in which my server downloads a file and the user can do the same almost simultaneously. I already think about the problem "If the user downloads fastly than the server...", but it's not a problem at this moment.
To do so, I used the header and readfile functions of php. Here is my code :
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.$data['name'].'";');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.$data['size']);
readfile($remoteFile);
I must to use the Content-length header to set the proper size of the file and not the size that is downloaded when the user clicks on the link. However, after some seconds or minutes, download is stopped and I need to restart...
If you think about a solution, even if it didn't use the header(); function, please tell me.
Thank you in advance...
I have experienced that this is directly related to maximum runtime settings, that are enforced upon you if you run with safe_mode on.
If you have the option, try setting set_time_limit(0) and see if that makes it work.
if you have your own server, you should look into the mod_xsendfile module for apache, since that is built specifically to send large files to the user.
Oh, and its stupidly easy to use
header("X-Sendfile: $path_to_somefile");
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"$somefile\"");
exit;

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