Make definitions safer

In the index, there is `define("ENVIRONMENT", ....)`
However, for my case, and I guess a general case, the first line of the index loads a config file.
For me, that config file the ENVIRONMENT definition, so the index throws an error.

Solution:
Add to index:
if(!defined("ENVIRONMENT"))

Have you modified index.php? The first line in the default CI3.1.0 one defines the ENVIRONMENT constant.

Have you modified index.php? The first line in the default CI3.1.0 one defines the ENVIRONMENT constant.

I did. It seemed like the best place to load my bootstrap file. (only line I added)
My bootstrap file does:
- Headers setup (allow-origin, allow-methods, allow-headers)
- 'die' for OPTIONS requests (preflight requests should not be processed)
- Load from a JSON config file that is generated using an init process, and is different between servers, into constant definitions

I understand this is not the most ordinary case, because I am basically running a bootstrap code outside/before CI is loading, but I still think, that the case doesn't matter, and like before every function you write `if(!function_exists('is_php'))` that before every definition there would be a `!defined`

Specifically for my case, if you are interested to know, I load the settings from a config file, because I bring up machines and replications and stuff with a very simple process, and modifying the JSON file is a piece of cake compared to htaccess, because I am working both with Apache and with nginx. So I wanna be prepared for every scenario