Reading from file (require)

问题:

I have something like this: http://i.imgur.com/KPulyBg.png and im currently working on "admin" folder and inside of that i have "admin.php", but the problem is that i want to read "core/init.php" from there. Now i have this in admin.php

<?php
require '../includes/header.php';
?>

<?php
$user = new User();
if(!$user->isLoggedIn()){
    Redirect::to(404);
}
else if(!$user->hasPermission('admin')){
    Redirect::to(404);
}
?>
<div id="content">

</div>

<?php
require '../includes/footer.php';
?>

And inside the "includes/header.php" i have php require_once 'core/init.php'; but i get this for my admin page:

Warning: require(core/init.php): failed to open stream: No such file or directory in C:\xampp\htdocs\OOP\includes\header.php on line 2

Fatal error: require(): Failed opening required 'core/init.php' (include_path='.;C:\xampp\php\PEAR') in C:\xampp\htdocs\OOP\includes\header.php on line 2

I know i have to add ../ but then i get that error on my index.php page which must be run without that because its not inside the folder, it only runs header and footer from includes folder.

回答1:

As the documentation explains:

Files are included based on the file path given or, if none is given, the include_path specified.

...

If a path is defined — whether absolute (starting with a drive letter or \ on Windows, or / on Unix/Linux systems) or relative to the current directory (starting with . or ..) — the include_path will be ignored altogether.

How this applies to your code?

require_once 'core/init.php'; - PHP searches all the paths from the php.ini directive include_path. It appends core/init.php to each path from the list and checks if the path computed this way exists. Most probably it doesn't.

require_once './core/init.php'; - include_path doesn't matter; the provided relative path (core/init.php) is appended to the current directory to get the path of the file;

What's the solution?

None of the above ways actually works in practice.

The safest method to include files using subdirectories is to use the magic constant __DIR__ and the function dirname() to compute the correct file path.

require '../includes/header.php';

becomes

require dirname(__DIR__).'/includes/header.php';

and

require_once 'core/init.php';

becomes

require_once dirname(__DIR__).'/core/init.php';

because __DIR__ is the directory where the current file (includes/header.php) is located.

回答2:

Can you try to use $_SERVER["DOCUMENT_ROOT"] instead of "../" I think that will solve your issue about require operation.

<?php
require ($_SERVER["DOCUMENT_ROOT"].'/includes/header.php');
?>

<?php
$user = new User();
if(!$user->isLoggedIn()){
    Redirect::to(404);
}
else if(!$user->hasPermission('admin')){
    Redirect::to(404);
}
?>
<div id="content">

</div>

<?php
require ($_SERVER["DOCUMENT_ROOT"].'/includes/footer.php');
?>

You can find reference about DOCUMENT_ROOT key here: http://php.net/manual/en/reserved.variables.server.php

回答3:

Define in your header.php HEADER_DIR based on __FILE__ variable. Where __FILE__ is one of php's magic constants see here for more info: http://php.net/manual/en/language.constants.predefined.php

define('HEADER_DIR', dirname(__FILE__)); 

// then use it in all includes 
require HEADER_DIR . "/../core/init.php";
require HEADER_DIR . "../some_other_folder/some_file.php";