Many users of my site have reported problems downloading a large file (80 MB). I am using a forced download using headers. I can provide additional php settings if necessary. I am using the CakePHP framework, but this code is all regular php. I am using php 5.2 with apache on a dedicated virtual server from media temple, CentOS Linux. Do you see any problems with the following code:
set_time_limit(1500);
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"" . basename($file_path) . "\"");
header("Content-Length: ".$content_length);
header("Content-Transfer-Encoding: binary");
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private', false);
header('Pragma: public');
header('Expires: 0');
//Change this part
$handle = fopen($file_path, 'rb');
while (!feof($handle))
{
echo fread($handle, 4096);
ob_flush();
flush();
}
fclose($handle);
exit;
Basically, the problem being reported is that the download starts and then stops in the middle. I was thinking it was a problem with the time limit, so I add the set_time_limit code. I was using the php readfile function before, but that also did not work smoothly.
The problem with PHP-initiated http transfers is that they seldomly support partial requests:
GET /yourfile HTTP/1.1
Range: bytes=31489531-79837582
Whenever a browser encounters a transmission problem, it will try to resume the download. Your php script does not accomodate for that (it's not trivial, so nobody does).
So really avoid that. Redirect users to a static file and let your webserver handle it. If you need to handle authorization, use tricks like symlinks or rewriterules that check for session cookies or even a static permission file (./allowed/178.224.2.55-file-1). Any required extra HTTP headers can be injected likewise, or with a .meta file.
I don't see any trouble, but for S&G's try placing the set_time_limit inside the while loop. This ensures they don't hit a hard limit and (as long as the client's taking the information) the time-limit gets extended.
Related
For some reason, our webserver is not responding while it's serving large files.
We use the windows platform, because we need to remotely call Win32 applications in order to generate the file that is to be served. This file is served through PHP's function: fpassthru, using this code:
if (file_exists($file)) {
$handle = #fopen($file, "rb");
header('Content-Description: File Transfer');
header('Content-Type: video/mp4');
if($stream==0){
header('Content-Disposition: attachment; filename='.basename($filename.".mp4"));
}
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_end_clean();
fpassthru($handle);
exit;
}
These files are often over 1GB in size and takes a while to transfer, but during this time, the webserver will not serve any pages. My firefox indicates it's 'connecting' but nothing else. Note that somebody else is transferring this file, not me, so different IP, different session.
Any clue where to look? Obviously, it's intolerable to have to wait 5 minutes for a website.
Thanks in advance!
This is commonly caused when you do not close the session before you begin sending the file data. This is because the session cache file can only be opened by one PHP process at a time, therefore the download is effectively blocking all other PHP processes at session_start().
The solution is to call session_write_close() to commit the session data to disk and close the file handle before you start outputting the file data.
I have an mp3 on my server (urls are just examples):
http://www.my-server.com/myaudio.mp3
I have a php script on the server at:
http://www.my-server.com/testmp3.php
Which contains the following code (which I got here):
<?
$file = "myaudio.mp3";
if (file_exists($file)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($file));
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_clean();
flush();
readfile($file);
exit;
}
?>
Is this all I have to do to mimic the behavior so that both request behave the same way and return the exact same response? Or is there anything I'm missing.
I'm using some streaming code on iOS (not relevant here) and both requests stream the audio fine but I can't seek properly using the php request but I can with the mp3 request directly.
So without getting into details about the app itself I wanted to eliminate this one variable first. Is there anything I need to do to make sure that from another app's perspective these two request will return the exact same data?
Thanks for any input you can give me here.
Update
It turns out my question really should have read "how do you support seeking of an mp3 when returning from a php script?".
To support seeking, you often will have to support a range request.
From the RFC: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35
See also: Resumable downloads when using PHP to send the file?
Its probably better to handle this with a .htaccess modification rather than some PHP code.
Here's a link on htaccess to get you started.
If you have a whole directory of .mp3 files that you want to appear as downloads instead of playing it in browser, you'd simply modify the .htaccess file in that folder to include
AddType application/octet-stream .mp3
I am using the simple file downloading script:
if (file_exists($file)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($file));
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_clean();
flush();
readfile($file);
exit;
}
It is working on my localserver upto 200mb.
When i try this code in my website it downloads 173KB instead of 200MB file.
I checked everything, wrote some custom code (using ob functions and fread instead of readfile) but can't download big files.
Thank you for your answers.
I am using Apache 2.2, PHP 5.3
All PHP settings to deal with big files are ok. (execution times, memory limits, ...
One issue I have with the following code is you have no control over the output stream, your letting PHP handle it without knowing exactly what is going on within the background:
What you should do is set up an output system that you can control and replicated accros servers.
For example:
if (file_exists($file))
{
if (FALSE!== ($handler = fopen($file, 'r')))
{
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($file));
header('Content-Transfer-Encoding: chunked'); //changed to chunked
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
//header('Content-Length: ' . filesize($file)); //Remove
//Send the content in chunks
while(false !== ($chunk = fread($handler,4096)))
{
echo $chunk;
}
}
exit;
}
echo "<h1>Content error</h1><p>The file does not exist!</p>";
This is only basic but give it a go!
Also read my reply here: file_get_contents => PHP Fatal error: Allowed memory exhausted
It seems readfile can have issues with long files. As #Khez asked, it could be that the script is running for too long. A quick Googling resulted in a couple examples of chunking the file.
http://teddy.fr/blog/how-serve-big-files-through-php
http://www.php.net/manual/en/function.readfile.php#99406
One solution to certain scenarios is that you can use PHP-script to intelligently decide what file from where to download, but instead of sending the file directly from PHP, you could return a redirection to the client which then contains the direct link which is processed by the web server alone.
This could be done at least in two ways: either PHP-script copies the file into a "download zone" which for example might be cleaned from "old" files regularly by some other background/service script or you expose the real permanent location to the clients.
There are of course drawbacks as is the case with each solution. In this one is that depending on the clients (curl, wget, GUI browser) requesting the file they may not support redirection you make and in the other one, the files are very exposed to the outer world and can be at all times read without the (access) control of the PHP script.
Have you made sure your script can run long enough and has enough memory?
Do you really need output buffering ?
The real solution is to avoid using a PHP script for just sending a file to the client, it's overkill and your webserver is better suited for the task.
Presumably you have a reason for sending the files through PHP, perhaps users must authenticate first? If that is the case then you should use X-Accel-Redirect (if you're using nginx) or X-Sendfile (previously X-LIGHTTPD-send-file) on lighttpd.
If you're using Apache I've found a few references to mod_xsendfile but I've never used it personally, and I doubt it's installed for you if you have managed hosting.
If these solutions are untenable I apologise, but I really need more information on the actual problem: Why are you sending these files through PHP in the first place?
I have just moved a web application to a windows server and having some problems. One of it is -
application stores list of names of files in a database table. when a files is requested for download it is sent to output by sending proper headers (depending upon mime type and then a readfile("document location/filename.extension");
it works fine in firefox but if I try to download in IE it throws
IE can not dowload this document from
www.mysite.com .. IE was unable to
open this Internet site. The requested
file is either unavailable or cannot
be found. Please try again later.
As it was working fine on previous server (non-windows), I tried to print document location and it read somewhat like C:/Apache/htdocs/FILENAME.ext and I guess this C:/ is causing problem in IE but not in firefox??
How do I get it working right in IE??
Thanks
UPDATE
I have got it working by
adding some more headers among others .. I think first 2 are more important for IE or so (atleast working for me for now :)
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_clean();
flush();
It works :
if (strstr($_HTTP_USER_AGENT, "MSIE")) {
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: doit-revalider, post-check = 0, pré-check = 0");
header("Content-Type: application de téléchargement; name=\"$sFilename\"");
header("Content-Length: $iTaille");
header("Content-Disposition: attachment; filename=\"$sFilename\"");
header("Content-Transfer-Encoding: binary");
} else {
header("Content-Type: application de téléchargement; name=\"$sFilename\"");
header("Content-Length: $iTaille");
header("Content-Disposition: attachment; filename=\"$sFilename\"");
}
this question had already been answered here PHP: Force file download and IE, yet again
Is this by any chance over SSL? If so, there are a whole host of bugs in MSIE which could be affecting your app. Try setting a very short caching time.
If it works on Firefox using the the same server, then the problem unlikely to be anything to do with the path on the server. Although beware that (IME) IIS seems to tunnel authorization from MSIE clients (but not others) in some instances.
I write a script to force download mp3 files from a site. The code is working very fine but the problem is that it can't download large files. I tried it with a file of 9.21mb and it downloaded correctly, but whenever i try to use the code to download a file of 25mb, it simply gives me a cannot find server page or The website cannot display the page. So i now know it has problems downloading large files. Below is the code snippet that does the downloading of files.
header("Pragma: public");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false);
header("Content-type: application/force-download");
header("Content-Disposition: attachment; filename=\"".$dname.".mp3\";" );
header("Content-Transfer-Encoding: binary");
header("Content-Length: ".filesize($secretfile));
$downloaded=readfile($secretfile);
The displayed error is: HTTP 500 Internal Server Error
thank u very much for ur time guys.
It could be memory limits, but usually PHP will output an error saying that the memory limit has been reached.
Also, before all of that you should disable output compression if it's enabled:
if(ini_get('zlib.output_compression')) {
ini_set('zlib.output_compression', 'Off');
}
Sometimes IE can screw up if output compression is enabled.
Watch your PHP configuration for memory limits and timeouts
In php.ini :
memory_limit = 32M
max_execution_time = 300
Note that if you want to go really high in execution time you also need to change your web server timeout.
i simply gives me a cannot find server page or The website cannot display the page
Is this the error as displayed by Internet Explorer? Do you get any server-side errors? Did you check your server logs?
Try this:
// empty output buffer
while (ob_get_level()) {
ob_end_clean();
}
if (ini_get('output_buffering')) {
ini_get('output_buffering', false);
}
// function to encode quoted-string tokens
function rfc2822_quoteString($string) {
return '"'.preg_replace('/[^\x00-\x0C\x0E-\x21\x23-\x5B\x5D-\x7F]/', '\\\$0', $string).'"';
}
// HTTP headers
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.rfc2822_quoteString($dname.'.mp3'));
header('Content-Length: '.filesize($secretfile));
// send file
readfile($secretfile);
exit;