Relative paths : going down and up

问题

I have a bunch of directories, and I have trouble including some files. Here's my structure.

index.php

vian/vian.php

includes/overall/head_content.php

includes/overall/head.php

Here is my head_content.php.

testing text
<?php include 'includes/overall/head.php'; ?>
<div class="wrapper row3">
    <div id="container" class="clear"> 
        <div id="content">

I want to include that file in vian/vian.php

I use '../includes/overall/head_content.php';, and the path works since 'testing text' shows up. But it cannot include includes/overall/head.php. I vaguely understand why it doesn't work, but I can't figure out how to fix it.

'../includes/overall/head_content.php'; is used on all my pages, including index.php, which is in my root directory.

回答1:

In your structure:

 + index.php
 + vian
 |  ` vian.php
 ` includes
    + overall
        + head_content.php
        ` head.php

Each file has a specific relationship to the other. Because of that you can make use of relative links from one file to another.

Of help in PHP for that is the __DIR__ magic constant. It contains the directory in each file automatically. You can use it, to make the relative path an absolute one. Absolute paths are very robust.

Examples:

From index.php to includes/overall/head.php:
__DIR__ . '/includes/overall/head.php'
From includes/overall/head.php to vian/vian.php:
__DIR__ . '/../../vian/vian.php'
From includes/overall/head_content.php to includes/overall/head.php:
__DIR__ . '/head.php'

And so on and so forth.

回答2:

Try

<?php include 'head.php'; ?>

来源：https://stackoverflow.com/questions/13088553/relative-paths-going-down-and-up

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