Why would $_FILES be empty when uploading files to PHP?

user_120763 0
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I have WampServer 2 installed on my Windows 7 computer. I'm using Apache 2.2.11 and PHP 5.2.11. When I attempt to upload any file from a form, it seems to upload, but in PHP, the $_FILES array is empty. There is no file in the c:\wamp\tmp folder. I have configured php.ini to allow file uploads and such. The tmp folder has read/write privileges for the current user. I'm stumped.

HTML:

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
    <form enctype="multipart/form-data" action="vanilla-upload.php" method="POST">
        Choose a file to upload: <input name="uploadedfile" type="file" /><br />
        <input type="submit" value="Upload File" />
    </form>
</body>
</html>

PHP:

<?php
echo 'file count=', count($_FILES),"\n";
var_dump($_FILES);
echo "\n";
?>
file-upload apache php
22 Answers

Do not trust the temp folder location provided by sys_get_temp_dir if you're in a shared hosting environment.

Here is one more thing to check that has not yet been mentioned...

I assumed, naturally, that the folder where my PHP script stored temporary file uploads was /tmp. This belief was reinforced by the fact that echo sys_get_temp_dir() . PHP_EOL; returns/tmp. Also, echo ini_get('upload_tmp_dir'); returns nothing.

To verify that the uploaded file does in fact briefly appear in my /tmp folder, I added a sleep(30); statement to my script (as suggested here) and navigated to my /tmp folder in cPanel File Manager to locate the file. However, no matter what, the uploaded file was nowhere to be found there.

I spent hours trying to determine the reason for this, and implemented every suggestion that's been offered here.

Finally, after searching my website files for the query tmp, I discovered that my site contained other folders named tmp in different directories. I realized that my PHP script was actually writing the uploaded files to .cagefs/tmp. (The "Show Hidden Files" setting must be enabled in cPanel in order to view this folder.)

So, why does the sys_get_temp_dir function return inaccurate info?

Here's an explanation from the PHP.net webpage for sys_get_temp_dir (i.e., the top comment):

If running on a Linux system where systemd has PrivateTmp=true (which is the default on CentOS 7 and perhaps other newer distros), this function will simply return "/tmp", not the true, much longer, somewhat dynamic path.

This SO post delves into the issue, as well:

user_88406170

Detach your form form the page you-re using into a simple php page that has the form and php code only, and test it like that.

Any bootstrap or java script might clean out the _FILES[]. That was my case

user_21954630

If you're using AJAX instead of a Form submission, then ensure the request header Content-Type is set to multipart/form-data; boundary=myAwesomeBoundary' where myAwesomeBoundary is the unique string that separates the request body parts. I made the mistake of overriding the Content-Type header by setting it to only multipart/form-data without setting the boundary. The fix was to not override the header but let the browser generate it for me.

user_39799060
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