In PHP scripts, whether calling include(), require(), fopen(), or their derivatives such as include_once, require_once, or even, move_uploaded_file(), one often runs into an error or warning:
Failed to open stream : No such file or directory.
What is a good process to quickly find the root cause of the problem?
This question is related to
php
require
fopen
include-path
Samba Shares
If you have a Linux test server and you work from a Windows Client, the Samba share interferes with the chmod command. So, even if you use:
chmod -R 777 myfolder
on the Linux side it is fully possible that the Unix Group\www-data still doesn't have write access. One working solution if your share is set up that Windows admins are mapped to root: From Windows, open the Permissions, disable Inheritance for your folder with copy, and then grant full access for www-data.
To add to the (really good) existing answer
open_basedir is one that can stump you because it can be specified in a web server configuration. While this is easily remedied if you run your own dedicated server, there are some shared hosting software packages out there (like Plesk, cPanel, etc) that will configure a configuration directive on a per-domain basis. Because the software builds the configuration file (i.e. httpd.conf) you cannot change that file directly because the hosting software will just overwrite it when it restarts.
With Plesk, they provide a place to override the provided httpd.conf called vhost.conf. Only the server admin can write this file. The configuration for Apache looks something like this
<Directory /var/www/vhosts/domain.com>
<IfModule mod_php5.c>
php_admin_flag engine on
php_admin_flag safe_mode off
php_admin_value open_basedir "/var/www/vhosts/domain.com:/tmp:/usr/share/pear:/local/PEAR"
</IfModule>
</Directory>
Have your server admin consult the manual for the hosting and web server software they use.
It's important to note that executing a file through your web server is very different from a command line or cron job execution. The big difference is that your web server has its own user and permissions. For security reasons that user is pretty restricted. Apache, for instance, is often apache, www-data or httpd (depending on your server). A cron job or CLI execution has whatever permissions that the user running it has (i.e. running a PHP script as root will execute with permissions of root).
A lot of times people will solve a permissions problem by doing the following (Linux example)
chmod 777 /path/to/file
This is not a smart idea, because the file or directory is now world writable. If you own the server and are the only user then this isn't such a big deal, but if you're on a shared hosting environment you've just given everyone on your server access.
What you need to do is determine the user(s) that need access and give only those them access. Once you know which users need access you'll want to make sure that
That user owns the file and possibly the parent directory (especially the parent directory if you want to write files). In most shared hosting environments this won't be an issue, because your user should own all the files underneath your root. A Linux example is shown below
chown apache:apache /path/to/file
The user, and only that user, has access. In Linux, a good practice would be chmod 600 (only owner can read and write) or chmod 644 (owner can write but everyone can read)
You can read a more extended discussion of Linux/Unix permissions and users here
The following PHP settings in php.ini if set to non-existent directory can also raise
PHP Warning: Unknown: failed to open stream: Permission denied in Unknown on line 0
sys_temp_dir
upload_tmp_dir
session.save_path
That was my case. It actually links to question #4485874, but I'm going to explain it here shortly.
When you try to require path/to/script.php?parameter=value, PHP looks for file named script.php?parameter=value, because UNIX allows you to have paths like this.
If you are really need to pass some data to included script, just declare it as $variable=... or $GLOBALS[]=... or other way you like.
For me I got this error because I was trying to read a file which required HTTP auth, with a username and password. Hope that helps others. Might be another corner case.
My code worked fine on all machines but only on this one started giving problem (which used to work find I guess). Used echo "document_root" path to debug and also looked closely at the error, found this
Warning: include(D:/MyProjects/testproject//functions/connections.php): failed to open stream:
You can easily see where the problems are. The problems are // before functions
$document_root = $_SERVER['DOCUMENT_ROOT'];
echo "root: $document_root";
include($document_root.'/functions/connections.php');
So simply remove the lading / from include and it should work fine. What is interesting is this behaviors is different on different versions. I run the same code on Laptop, Macbook Pro and this PC, all worked fine untill. Hope this helps someone.
Source: Stackoverflow.com