Include function in php - php

Question

I have a navigation bar page that I can use for all the pages in my website. However, I built a new login page but it is having errors when I connect to the navigation bar page.
The structure of all my files:
I want to apply the navigation bar to my login.php under the uploadTesting2 file. The code for navigation bar I have put in my login.php is :
<?php include '../navHeader.php'; ?>
The code in the navHearder.php is:
<div class="collapse navbar-collapse navHeaderCollapse">
<ul class="nav navbar-nav navbar-right">
<li class="active">About</li>
<li>News</li>
<li class="dropdown">
Collection <b class="caret"></b>
<ul class="dropdown-menu">
<?php
include './data.php';
for ($i = 0; $i < count($collectionArr); $i++) {
echo '<li>';
echo '<a href=\'collectionPage.php?cat=' . $collectionArr[$i]['catCode'] . '\'>';
echo $collectionArr[$i]['catName'];
echo '</a>';
echo '</li>';
}
?>
</ul>
</li>
<li>Ordering</li>
<li>Contact</li>
<li>Admin</li>
</ul>
</div>
However, the code is not working. When I click the index.php, it will show error. the url is wrong and the url is showing: http://localhost:7777/ca2/CA2script/uploadTesting2/index.php
Should I apply one more navgation php in my uploadTesting2 or I can make changes in the navHeader.php?

Answer 1

For best practice define your main(base) url as constant then use it any where.
Suppose your base url is "http://localhost:7777/ca2/CA2script/"
You can do it like following:
define('BASE_URL',"http://localhost:7777/ca2/CA2script/");
then in any file you can use it for link
Ex: in your navHearder.php use like this:
<li class="active">About</li>
suppose your file is in directory then:
link

Answer 2

Problem with include
The include statement relates file according to the location relative to the entry point. For example, if you have a file structure like this:
/
/uploadTesting2
/login.php
/navHeader.php
/data.php
When you visits /uploadTesting2/login.php as the entry point, the location of navHeader.php and data.php should be ../navHeader.php and ../data.php. This is true even within the scripts included by login.php. So navHeader.php should only find data.php in as ../data.php.
A usual way to solve this issue is to use __DIR__ constant as a reference. This constant will always to be the script file's parent folder (not the entry file). If you echo __DIR__ inside navHeader.php, it will be the system path of your root no matter what is including it.
Thus instead of this include statement:
include './data.php';
you may do this:
include __DIR__ . '/data.php';
Problem with links
Links is also resolved relative to your current path. Thus
<a href="collectionPage.php?cat=abc">
in /uploadTesting2/index.php URL resolves to /uploadTesting2/collectionPage.php?cat=abc. Instead you should do
<a href="../collectionPage.php?cat=abc">