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dotenv: Environmental Variables

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The $debug and $environment variables are hardcoded in index.php. So if we deploy this, we'll either have a web debug toolbar on production, or we'll need to manually modify this file to set $debug to false. Both situations stink.

PHP dotenv Fanciness

To help, we'll install a new library: composer require vlucas/phpdotenv:

composer require vlucas/phpdotenv

While we're waiting, Google for that library and find its documentation.

This is a popular library these days, and I really like it too. It allows you to have a .env file at the root of your project. It'll look something like this:


This library reads these values and turns S3_BUCKET and SECRET_KEY into environment variables. Then, in our app, whenever we need some configuration - like whether we're in debug mode, the database password or the S3 bucket - we'll read from the environment variables. When you eventually deploy, you can set those variables in two different ways. First, you can have a .env file. Or second, you can set the variables via something like your web server configuration. Some platforms - like Heroku also have a way to set environment variables. The important point is that your app isn't bound to a configuration file: it's just reading environment variables, which is a pretty standard way of setting config.

Our .env File

The first things we want to set are the $env and $debug flags. Create a .env file and say SYMFONY_ENV=dev and SYMFONY_DEBUG=1:

4 lines .env
# basic setup

Remove the old variables in index.php. Replace it with $dotenv = new DotEnv\DotEnv(). The argument is the directory where the .env file lives - it's actually up one directory from here. Then, call $dotenv->load():

26 lines web/index.php
... lines 1 - 9
// load the environmental variables
$dotenv = new Dotenv\Dotenv(__DIR__.'/../');
... lines 13 - 26

At this point, those two flags have been set as environment variables. That means we can say $env = $_SERVER['SYMFONY_ENV']; and $debug = $_SERVER['SYMFONY_DEBUG'];:

26 lines web/index.php
... lines 1 - 9
// load the environmental variables
$dotenv = new Dotenv\Dotenv(__DIR__.'/../');
... lines 15 - 26

Go back and refresh the new setup - we should still see the toolbar. Yep, there it is. But now go back to .env and set SYMFONY_DEBUG to 0. Because of config.yml, this should turn the toolbar off. Change the environment to prod too - that's not being used anywhere yet, but it may avoid a temporary cache error:

4 lines .env
# basic setup

Try it out: no web debug toolbar.

Add .env to the .gitignore file - this shouldn't be committed:

5 lines .gitignore
... lines 1 - 3

But copy .env to .env.example - we will commit this so that new developers have something they can use as a guide.

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What PHP libraries does this tutorial use?

// composer.json
    "require": {
        "symfony/symfony": "^2.7", // v2.7.2
        "sensio/framework-extra-bundle": "^3.0", // v3.0.9
        "vlucas/phpdotenv": "^2.0", // v2.0.1
        "symfony/monolog-bundle": "^2.7" // v2.7.1