PHP - Need Help Declaring And Using a Constant

Question

I'm new to PHP. I've been looking at the documentation and am having a problem. I have a multi-page PHP site I am working on. I was having a problem with relative paths (PHP Relative Path Issues) and was pointed to the following url(PHP include relative path). I want to use something similar to the following code snippet in the post:

if (is_production()) {
    define('ROOT_PATH', '/some/production/path');
}
else {
    define('ROOT_PATH', '/root');
}
include ROOT_PATH . '/connect.php';

On what page do I add the define statement (index.php?) and how can I reference the ROOT_PATH on every subsequent page that has an include statement?

I tried adding the define statement to the index.php page but calling the ROOT_PATH on any other page results in: Use of undefined constant ROOT_PATH

Index.php: define('ROOT_PATH', '/some/production/path');
some other page: include_once(ROOT_PATH."/Library/API/database.inc.php");

you create a config file for all environment variable and add this file to all of your php files @FlyFish — Parth Mahida, Nov 10 '16 at 18:06
@RyanVincent I tried adding the define statement to the index.php but it wasn't being recognized on any subsequent pages. — FlyFish, Nov 10 '16 at 18:29
To expand on @parthmahida ... create a file called something like config.php and in there, add all of your configs, constants, etc ... then on each page, include the config.php file at the top. — Spechal, Nov 10 '16 at 18:42
@Spechal I'm stuck at the issue that started this. How do I reference the config file without using the complete absolute path Which is what I am trying to avoid in the first place. — FlyFish, Nov 10 '16 at 19:01
I'm doing something wrong. I created a config.php file. I added in the following: return array('ROOT_PATH' => 'C:/Users/Me/Documents/app/site'); I added an include (include_once(ROOT_PATH."/Library/API/database.inc.php"); )to the file at the top of the page, but I get the following error: Notice: Use of undefined constant ROOT_PATH - assumed 'ROOT_PATH' — FlyFish, Nov 10 '16 at 19:18

score 0 · Answer 1 · answered Nov 10 '16 at 18:47

0

You have 2 possible (common) approaches:

Create files for each environment like production.inc.php and development.inc.php and include the one you need in your index.php by using your is_production() condition.

-- OR --

Create a single file that contains

if (is_production()) {
    define('ROOT_PATH', '/some/production/path');
} else {
    define('ROOT_PATH', '/root');
}

and then just include that single file to all your pages that need those constants.

answered Nov 10 '16 at 18:47

dokgu

4,957
3
39
77

I think I wasn't clear. I'm only looking to have a SINGLE define statement. My issue is that I can't figure out how to populate the 'ROOT_PATH' constant and then access it on other pages. – FlyFish Nov 10 '16 at 18:58
@FlyFish that's what I meant with the last sentence on my answer. Just do `include_once("config.inc.php");` on all the pages that needs to access the contant. – dokgu Nov 10 '16 at 21:02

score 0 · Answer 2 · answered Nov 10 '16 at 20:55

0

I believe my issue was a SCOPING Issue. Although I went with @ parthmahida and @Spechal suggestion, there was still an issue. I ended up having to look at scoping to see it in the functions.

answered Nov 10 '16 at 20:55

FlyFish

491
5
22

score 0 · Answer 3 · answered Nov 10 '16 at 22:17

If you want to include a file that will contain your environment configuration information and constants, it will always have to be relative to the script calling it.

<?php

// config.php
function is_production(){ // do something to return boolean }
if (is_production()) {
    define('ROOT_PATH', '/some/production/path');
}
else {
    define('ROOT_PATH', '/root');
}

...

<?php

// index.php
include 'config.php';
include ROOT_PATH . 'some-file.php';
// do stuff

...

<?php

// some-page.php
include 'config.php';
include ROOT_PATH . 'other-file.php';
// do stuff

PHP - Need Help Declaring And Using a Constant

3 Answers3