This question already has answers here:
What is double dot(..) and single dot(.) in Linux?
(4 answers)
Closed 4 years ago.
I am working on a PHP website where I needed to get a list of the files in the Images directory. The example in PHP.net shows the addressing with just a forward slash as shown in the example. This addressing pattern did not work. Instead the address needs to start with ./ . What is the difference?
<?php
$dir = '/tmp';
$files1 = scandir($dir);
$files2 = scandir($dir, 1);
print_r($files1);
print_r($files2);
?>
A search for other questions have addressed single dot and double dot, but I don't see posts for a forward slash with no dot.
the . indicates the current directory. Assume, for instance, that your current path is /var/www:
If you say ./tmp the directory you are looking for is /var/www/tmp
If you say /tmp you are looking for /tmp (starting from the root)
Maybe you're a Windows user and you are not familiar with the way Linux addresses files, but essentially there are no drive letters. / is the root of the file system, basically equivalent to C:\ on Windows (though not quite). It also works on Windows except it will refer to the root of the partition your script is running in as Windows separates each partition on a different drive letter.
There's a standard folder in the root of the file system called tmp, and if you want to refer to it you want to specify full path, /tmp.
Just using tmp or ./tmp will refer to a tmp folder on your local path, which is a completely different folder just with the same name (that might not even exist).
When you don't want to specify a full path but somewhere relative or local path instead, you don't put / in the beginning. You might just put nothing, or you can put ./ to explicitate this is a path relative to your current working directory which is ..
It doesn't matter in which folder your script working, . always represents it. It is actually unnecessary to put ./ in most cases since relative paths are implicit.
On a relate note, .. represents the parent folder.
Example, my script is /var/www/script.php, when I run it:
. is the folder /var/www.
fopen('note.txt', 'r') will open file /var/www/note.txt for reading.
fopen('./note.txt', 'r') will do the exact same thing.
.. is the folder /var.
../../tmp is the same as /tmp.
Note the current working directory represented by . remains constant even if you include() a script from a subfolder.
This might get things confusing because . may not be the folder the script you included is in. To workaround this problem, use __DIR__ to get the folder your script is in, it will get the current folder of your script even if you are calling it through a include() or calling it from a different directory.
/ denotes the root directory of your server. As in /var/www/.
./ denotes the current directory that the script is executing in. This is the equivalent of getcwd(). For example, you're currently in /php/scripts, it will refer to /var/www/php/scripts.
../ denotes the parent folder, and can be chained to move up multiple levels.
The use of each depends on which file or folder you're trying to manipulate from which script.
If you're trying to access /var/www/tmp from /var/www/php/scripts/script.php, you can use either:
../../tmp
/tmp
Note that if you're unsure how many levels you need to 'move up', you can affix an infinite number of ../; it won't 'break out' of the root. Having said that, referencing directly from the root is often much more straight-forward.
Related
This question already has answers here:
What is double dot(..) and single dot(.) in Linux?
(4 answers)
Closed 5 years ago.
I always use require('dbc.php'); to include file but what is the difference when I prefix 2 dots ../ as below, is there is any extra security.
require('../dbc.php');
require('../lib/bootstrap.php');
require_once '../../../conf/config.php';
If you do
../../
You've gone back two directory
../
You've gone back one directory
This basically going out the current directory the file u are working on is in. It depends on the location of the db file relative to the file that needs it. It has nothing to do with security.
The . gives you the ability to set the path of the included files relatively to the path of the original file that run (the file that included them). The ./ indicates the current directory. So if including a file like such:
require('./config.php')
You are telling PHP to look in the current directory for "config.php". Which is the same as
require('config.php')
The ../ indicates the directory above or "parent directory"
require('../dbc.php');
This is telling PHP to go one directory up and look for "dbc.php".
These commands can be chained like so:
require('../lib/bootstrap.php');
require_once '../../../conf/config.php';
The dots simply are used to traverse the directory structure. What is double dot(..) and single dot(.) in Linux?, though you should avoid using relative paths and use absolute paths. Absolute vs. relative paths.
Security:
In its self, it introduces no security benefits, except if you get it wrong your app won't work at all!
It does add some protection against code disclosure if PHP fails to parse. This applies ONLY if you store your main code outside of the webroot, though I have never encountered or seen this issue spontaneously happen, though it possibly could. Storing script files outside web root.
I was curious if ../ and /../ is the same in PHP so I tried these:
require_once('/../frame/header.php');
require_once('../frame/header.php');
Both of them worked. Was I just lucky or they realy do the same exact thing? Why?
In your context if they both worked, that implies that your scripts are at the root of the filesystem you have access to, or one level in. They are not the same however! /../ refers to the filesystem root (and .. one directory up, which just gets eaten and is still the root), while ../ refers to one directory higher than the current one. Any path beginning with / is an absolute path from the filesystem root.
From anywhere other than the filesystem root, these would not function equivalently.
Suppose your working directory is /var/www/scripts.
require_once('../include.php');
Will include a file at /var/www/include.php.
But from that same location, if you did
require_once('/../include.php');
...php will attempt to load the file /include.php at the filesystem root, and it probably won't exist.
Now, a lot of web hosts will supply you with a filesystem whose root / is also the web server's document root, the web server document root is only one directory level in from the root like /www. In that case, /../ may work fine, but beware if you ever attempt to move it to another server with a different filesystem configuration.
So if the script's working directory was /www, just by luck, these two would function the same way:
require_once('../include.php');
require_once('/../include.php');
Both would include the file /include.php at the filesystem root.
Note, this is not PHP-specific, but a property of filesystems which use the .. in general...
Preceding any link with a / mean that you are coming from the root of the context you are in. If you are already in the root directory, or a chroot jail, then both statements are the same.
I'm needing to include a file from the parent directory, and other sub-directories, into a sub-directory. I've done it before by simply using include('/rootdirectory/file.php'); but now it won't seem to work.
Just wondering how I can do this, thanks.
Here's my exact line:
include('/forums/groups.php');
It's giving me this error(the page still runs):
Warning: include(/forums/groups.php) [function.include]: failed to
open stream: No such file or directory in
C:\xampp\htdocs\forums\blog\posts.php on line
Warning: include() [function.include]: Failed opening
'/forums/groups.php' for inclusion
(include_path='.;C:\xampp\php\PEAR') in
C:\xampp\htdocs\forums\blog\posts.php on line 3
include() and its relatives take filesystem paths, not web paths relative to the document root. To get the parent directory, use ../
include('../somefilein_parent.php');
include('../../somefile_2levels_up.php');
If you begin with a /, an absolute system file path will be used:
// Full absolute path...
include('/home/username/sites/project/include/config.php');
If your server is not resolving the file from the parent directory using
include '../somefilein_parent.php'
try this (using the parent directory relative to the script):
include __DIR__ . "/../somefilein_parent.php";
Here's something I wrote with that problem in mind:
<?
function absolute_include($file)
{
/*
$file is the file url relative to the root of your site.
Yourdomain.com/folder/file.inc would be passed as
"folder/file.inc"
*/
$folder_depth = substr_count($_SERVER["PHP_SELF"] , "/");
if($folder_depth == false)
$folder_depth = 1;
include(str_repeat("../", $folder_depth - 1) . $file);
}
?>
hope it helps.
Depends on where the file you are trying to include from is located.
Example:
/rootdir/pages/file.php
/someotherDir/index.php
If you wrote the following in index.php:
include('/rootdir/pages/file.php');it would error becuase it would try to get:
/someotherDir/rootdir/pages/file.php Which of course doesn't exist...
So you would have to use include('../rootdir/pages/file.php');
In laymans terms, and practicality, I see this as an old DOS trick/thing. Whoa! What was that? DOS? Never heard of it!
".." backs you out of the current sub-directory one time to a higher folder/directory, and .. enter typed twice backs you out too 2 higher parent folders. Keep adding the ".. enter" back to back and you will soon find yourself at the top level of the directory.
As for Newbies to understand this better, consider this (in terms of the home PC or "C:\ drive" if you know what that means, rather than the web-servers/host "root directory" ). While your at it, Consider your website existing somewhere on your home PC's hard drive, buried in some folder under the C:\ drive. Lastly, you can think of it as ".." is back one directory and "/" is forward one directory/folder.
Now!
If you are using the command prompt and are within the "myDocuments" folder of your PC you must back out of that folder to get closer to the higher directory "C:\" by typing the "../".
If you wanted to access a file that is located in the widows directory while you are still in the myDocuments folder you would theoretically type ../windows; in reality of DOS command prompt you would simply type .., but I am setting you up for the web. The / redirects forward to another directory naturally.
Using "myDocuments" lets pretend that you created 2 folders within it called "PHP1" and "PHP2", in such we now have the folders:
C:\myDocuments\PHP1
C:\myDocuments\PHP2
In PHP1 you place a file called index.php. and in PHP2 folder you placed a file called Found.php. it now becomes:
C:\myDocuments\PHP1\index.php
C:\myDocuments\PHP2\found.php
Inside the
C:\myDocuments\PHP1\index.php file you would need to edit and type something like:
<?php include ('../php2/found.php')?>
The ../ is positional thus it considers your current file location "C:\myDocuments\PHP1\index.php" and is a directive telling it to back out of PHP1 directory and enter or move forward into PHP2 directory to look for the Found.php file. But does it read it? See my thoughts on trouble shooting below.
Now! suppose you have 1 folder PHP1 and a sub-folder PHP2:
C:\myDocuments\PHP1\PHP2
you would simply reference/code
<?php include('/PHP2/found.php') ?>
as PHP2 exist as a sub-directory, below or within PHP1 directory.
If the above does not work it may have something to do with access/htaccess or permission to the directory or a typo. To enhance this...getting into trouble shooting...If the "found.php" file has errors/typo's within it, it will crash upon rendering at the error, such could be the reason (require/require_once) that you are experiencing the illusion that it is not changing directories or accessing the file.
At last thought on the matter, you may need to instantiate your functions or references in order to use the included/require "whatever" by creating a new variable or object such as
$newObject = new nameobject("origianlThingy");
Remember, just because you are including/requiring something, sometimes means just that, it is included/required to run, but it might need to be recreated to make it active or access it. New will surely re-create an instance of it "if it is readable" and make it available within the current document while preserving the original. However you should reference the newly created variable $newObject in all instances....if its global.
To put this in perspective of some web host account; the web host is some whopping over sized hard-drive (like that on your PC) and your domain is nothing more than a folder they have assigned to you. Your folder is called the root. Inside that folder you can do anything you are allowed to do.
your "one of many ways" to move between directories/folders is to use the ../ however many times to back out of your current in reference to folder position you want to find.
In my drunken state I realize that I know too much to be sane, and not
enough to be insane!"
Any path beginning with a slash will be an absolute path. From the root-folder of the server and not the root-folder of your document root. You can use ../ to go into the parent directory.
You may interest in using php's inbuilt function realpath().
and passing a constant DIR
for example:
$TargetDirectory = realpath(__DIR__."/../.."); //Will take you 2 folder's back
String realpath() :: Returns canonicalized absolute pathname ..
I took inspiration from frank and I added something like this in my "settings.php" file that is then included in all pages when there is a link:
"settings.php"
$folder_depth = substr_count($_SERVER["PHP_SELF"] , "/");
$slash="";
for ($i=1;$i<=($folder_depth-2);++$i){
$slash= $slash."../";
}
in my header.php to be included in all pages:
a href= .... php echo $slash.'index.php'....
seems it works both on local and hosted environment....
(NOTE: I am an absolute beginner )
Had same issue earlier solved like this :
include('/../includes/config.php'); //note '/' appearing before '../includes/config.php'
the root directory (in PHP) is the directory of the file that is pinged. For example, I go to http://localhost/directory/to/file/index.php, the root directory will be "/dictory/to/file", since it's the one that you've made a web request for.
I can't believe none of the answers pointed to the function dirname() (available since PHP 4).
Basically, it returns the full path for the referenced object. If you use a file as a reference, the function returns the full path of the file. If the referenced object is a folder, the function will return the parent folder of that folder.
https://www.php.net/manual/en/function.dirname.php
For the current folder of the current file, use $current = dirname(__FILE__);.
For a parent folder of the current folder, simply use $parent = dirname(__DIR__);.
If your configuration file PHP.ini is set up correctly then you can use:
include($_SERVER["DOCUMENT_ROOT"]."/my_script.php");
// or
require($_SERVER["DOCUMENT_ROOT"]."/my_script.php");
Okay so I'm learning about uploads and need to copy the tmp file to a specified directory so I use the copy command.
I use this inside my index.php of the main directory (learningupload/ folder)
copy($_FILES['photo']['tmp_name']['file'], './pics/'.$photoname.'.jpg');
Now I'm doing this on Xampp local host, and my uploads go to the tmp folder which is of course different from where I want the upload to go
so there's
C:\xampp\tmp
C:\xampp\htdocs\learningupload\pics\
My question is this: What is this ./ inside the destination string I need to have? Doesn't it usually mean you're moving UP a directory? Why not have it '/pics' no dot? I tried that and said it couldn't open the stream. Does the dot here mean it's referring to whatever directory index.php is in? Or am I thinking ../ moves up a directory? And single dot is different?
Thanks.
./ means "current working directory". Which directory is current working one you can see with echo getcwd();
The parent directory (the upper one) is ../
You can change your working directory using chdir() or you can just specify the full path instead.
In HTML, I can find a file starting from the web server's root folder by beginning the filepath with "/". Like:
/images/some_image.jpg
I can put that path in any file in any subdirectory, and it will point to the right image.
With PHP, I tried something similar:
include("/includes/header.php");
...but that doesn't work.
I think that that this page is saying that I can set include_path once and after that, it will be assumed. But I don't quite get the syntax. Both examples start with a period, and it says:
Using a . in the include path allows for relative includes as it means the current directory.
Relative includes are exactly what I don't want.
How do I make sure that all my includes point to the root/includes folder? (Bonus: what if I want to place that folder outside the public directory?)
Clarification
My development files are currently being served by XAMPP/Apache. Does that affect the absolute path? (I'm not sure yet what the production server will be.)
Update
I don't know what my problem was here. The include_path thing I referenced above was exactly what I was looking for, and the syntax isn't really confusing. I just tried it and it works great.
One thing that occurs to me is that some people may have thought that "/some/path" was an "absolute path" because they assumed the OS was Linux. This server is Windows, so an absolute path would have to start with the drive name.
Anyway, problem solved! :)
What I do is put a config.php file in my root directory. This file is included by all PHP files in my project. In that config.php file, I then do the following;
define( 'ROOT_DIR', dirname(__FILE__) );
Then in all files, I know what the root of my project is and can do stuff like this
require_once( ROOT_DIR.'/include/functions.php' );
Sorry, no bonus points for getting outside of the public directory ;) This also has the unfortunate side affect that you still need a relative path for finding config.php, but it makes the rest of your includes much easier.
One strategy
I don't know if this is the best way, but it has worked for me.
$root = $_SERVER['DOCUMENT_ROOT'];
include($root."/path/to/file.php");
The include_path setting works like $PATH in unix (there is a similar setting in Windows too).It contains multiple directory names, seperated by colons (:). When you include or require a file, these directories are searched in order, until a match is found or all directories are searched.
So, to make sure that your application always includes from your path if the file exists there, simply put your include dir first in the list of directories.
ini_set("include_path", "/your_include_path:".ini_get("include_path"));
This way, your include directory is searched first, and then the original search path (by default the current directory, and then PEAR). If you have no problem modifying include_path, then this is the solution for you.
There is nothing in include/require that prohibits you from using absolute an path.
so your example
include('/includes/header.php');
should work just fine. Assuming the path and file are corect and have the correct permissions set.
(and thereby allow you to include whatever file you like, in- or outside your document root)
This behaviour is however considered to be a possible security risk. Therefore, the system administrator can set the open_basedir directive.
This directive configures where you can include/require your files from and it might just be your problem.
Some control panels (plesk for example) set this directive to be the same as the document root by default.
as for the '.' syntax:
/home/username/public_html <- absolute path
public_html <- relative path
./public_html <- same as the path above
../username/public_html <- another relative path
However, I usually use a slightly different option:
require_once(__DIR__ . '/Factories/ViewFactory.php');
With this edition, you specify an absolute path, relative to the file that contains the require_once() statement.
Another option is to create a file in the $_SERVER['DOCUMENT_ROOT'] directory with the definition of your absolute path.
For example, if your $_SERVER['DOCUMENT_ROOT'] directory is
C:\wamp\www\
create a file (i.e. my_paths.php) containing this
<?php if(!defined('MY_ABS_PATH')) define('MY_ABS_PATH',$_SERVER['DOCUMENT_ROOT'].'MyProyect/')
Now you only need to include in every file inside your MyProyect folder this file (my_paths.php), so you can user MY_ABS_PATH as an absolute path for MyProject.
Not directly answering your question but something to remember:
When using includes with allow_url_include on in your ini beware that, when accessing sessions from included files, if from a script you include one file using an absolute file reference and then include a second file from on your local server using a url file reference that they have different variable scope and the same session will not be seen from both included files. The original session won't be seen from the url included file.
from: http://us2.php.net/manual/en/function.include.php#84052
hey all...i had a similar problem with my cms system.
i needed a hard path for some security aspects.
think the best way is like rob wrote. for quick an dirty coding
think this works also..:-)
<?php
$path = getcwd();
$myfile = "/test.inc.php";
/*
getcwd () points to:
/usr/srv/apache/htdocs/myworkingdir (as example)
echo ($path.$myfile);
would return...
/usr/srv/apache/htdocs/myworkingdir/test.inc.php
access outside your working directory is not allowed.
*/
includ_once ($path.$myfile);
//some code
?>
nice day
strtok
I follow Wordpress's example on this one. I go and define a root path, normally the document root, and then go define a bunch of other path's along with that (one for each of my class dirs. IE: database, users, html, etc). Often I will define the root path manually instead of relying on a server variable.
Example
if($_SERVER['SERVERNAME'] == "localhost")
{
define("ABS_PATH", "/path/to/upper/most/directory"); // Manual
}
else
{
define("ABS_PATH, dirname(__FILE__));
// This defines the path as the directory of the containing file, normally a config.php
}
// define other paths...
include(ABS_PATH."/mystuff.php");
Thanks - this is one of 2 links that com up if you google for php apache windows absolute path.
As a newbie to intermed PHP developer I didnt understand why absolute paths on apache windopws systems would be c:\xampp\htdocs (apache document root - XAMPP default) instead of /
thus if in http//localhost/myapp/subfolder1/subfolder2/myfile.php I wanted to include a file from http//localhost/myapp
I would need to specify it as:
include("c:\xampp\htdocs\myapp\includeme.php")
or
include("../../includeme.php")
AND NOT
include("/myapp/includeme.php")
I've come up with a single line of code to set at top of my every php script as to compensate:
<?php if(!$root) for($i=count(explode("/",$_SERVER["PHP_SELF"]));$i>2;$i--) $root .= "../"; ?>
By this building $root to bee "../" steps up in hierarchy from wherever the file is placed.
Whenever I want to include with an absolut path the line will be:
<?php include($root."some/include/directory/file.php"); ?>
I don't really like it, seems as an awkward way to solve it, but it seem to work whatever system php runs on and wherever the file is placed, making it system independent.
To reach files outside the web directory add some more ../ after $root, e.g. $root."../external/file.txt".