Creating a library of classes in php - how to handle the library root location?

Question

I am about to create a collection of classes in php which are interrelated. Now I would like to include files using their absolute path, ie

If I were in

'/com/mysite/licences/Generator.class.php'

I would like to include files like this:

include '/com/mysite/lib/Utils.class.php'

I don't want to include like this, I think it is confusing and ugly

include '../licenses/Utils.class.php'

This works ok, unless 'com' is not in the root of public_html. I assume I will need some sort of prefix to append to each file LIBRARY_ROOT that hold the location of 'com' in the current filesystem. So it might look like this

include LIBRARY_ROOT.'com/mysite/lib/Utils.class.php'

What is the best way to do this?

-----------------MY SOLUTION----------------

UPDATE :

It looks like this solution didn't work either because the set_include_path('/'); appears to reset at the closing php tag ?> not the one in the including file.

---

This is what I did

Created a file called like the following in the root of the filesytem

com.mysite.setup.inc.php

the long name is in the Java format for package names, it is like this to help prevent naming conflicts. If I called it setup.php it is possible that another file will also be called setup.php in the root folder.

com.mysite.setup.inc.php contains the following:

<?php
/**
 * Setup file for each class
 */

//Path
set_include_path('/');

//Other common setup

?>

This will always be in the root folder so all classes can call it like this:

include '/com.mysite.setup.inc.php';

If the library gets moved all you have to do is update com.mysite.setup.inc.php to reflect the changes.

What we get is a clean naming convention with no need to append ugly PREFIXES to every single include. We can now include like this in any class file.

include '/com.mysite.setup.inc.php';
include 'com/mysite/lib/Utils.class.php';
include 'com/mysite/lib/text_utilities/Text.class.php';
include 'com/mysite/encryption/Cipher.class.php';

class MyClass {.......

Answer 1

Just

define ('LIBROOT', $_SERVER['DOCUMENT_ROOT'].'/com/mysite/');

And include like

include LIBROOT. 'lib/Utils.class.php';

$_SERVER['DOCUMENT_ROOT'] will work in 99% cases.

Answer 2

You could alternatively consider setting the include_path to your library base directory, and just include("lib/utils.class.php").

Answer 3

Basing your path on DOCUMENT_ROOT can end up a little messy if your scripts are outside the document root (which ideally, they will be). You may also need to watch out for cross-platform compatibility when it comes to directory separators. Windows is usually not too fussy and will accept backslashes and forward slashes, but that tends not to be the case on other operating systems.

You could derive your library root path from the filename of a script. Choose a script with a path that, relative to your library, will remain constant. I usually have a script (called constants.php) which I call right at the start of my application. It defines a series of constants that are used in the application.

From there, I use SCRIPT_FILENAME to derive a path to my library files. This method means that you can move your scripts around on the filesystem, or to another filesystem, and they will still resolve the correct paths. I've included a quick and dirty function which breaks one or more paths down, then recombines them using the correct operating system directory separator:

In constants.php:

define(
    'MY_LIB',
    combine_path(
        dirname($_SERVER['SCRIPT_FILENAME']),
        'lib/my_lib'
    )
);

define(
    'THIRD_PARTY_LIB',
    combine_path(
        dirname($_SERVER['SCRIPT_FILENAME']),
        'lib/third_party_lib'
    )
);

function combine_path() {
    // Get an array of function arguments.
    $args = func_get_args();

    // Prepare an array to hold the list of path nodes.
    $path = array();

    // Process each argument.
    foreach ($args as $arg) {
        // Split the path at backslash or forward slash separators.
        $nodes = preg_split('/[\\/\\\]/', $arg);

        // Push each node onto the end of the path array.
        foreach ($nodes as $node) {
            $path[] = $node;
        }
    }

    // Join the path nodes with the system's directory separator.
    return implode(DIRECTORY_SEPARATOR, $path);
}

Answer 4

you should use the autoload function, and in your autoload keep going up a dir in a loop till you find you lib dir, then append the path onto the classfile you are looking for.

something like

<?php
function __autoload( $className ){
// where all your classes are. 
//you can add logic for namespaces fairly easily here as well
$classDir = "lib"; 
// the path to your library we wil modify this in the loop
$pathPrefix = '';

while( !is_dir( $pathPrefix . $classDir )){
    $pathPrefix .= '../';
}

if( file_exists( $pathPrefix . $classDir . DIRECTORY_SEPARATOR . $className . 'php' )){
    include( $pathPrefix . $classDir . DIRECTORY_SEPARATOR . $className . 'php' );
}else{
    throw new Exception( $className . ' could not be found by autoload' );
}

}