如何从PHP中获取环境变量PHP / phpinfo（）
我试图使用SendGrid的API，我需要使用以下命令访问我添加到我的根目录的环境变量。
I'm trying to use SendGrid's API for which I need to access an environment variable that I've added to my root directory using the following command.
echo "export SENDGRID_API_KEY='YOUR_API_KEY'" > sendgrid.env
echo "sendgrid.env" >> .gitignore
source ./sendgrid.env
这创建了一个我的根文件夹中的sendgrid.env 文件，将 sendgrid.env 添加到我的 .gitignore 文件，并将 SENDGRID_API_KEY 添加为环境变量。
This has created a sendgrid.env file in my root folder, added sendgrid.env to my .gitignore file, and added SENDGRID_API_KEY as an environment variable.
但是，PHP的 getenv 'SENDGRID_API_KEY'）键不返回任何东西，PHP的 phpinfo（）不反映 SENDGRID_API_KEY 作为一个环境变量。
However, PHP's getenv('SENDGRID_API_KEY') key is not returning anything, and PHP's phpinfo() does not reflect SENDGRID_API_KEY as an environment variable.
这里是 API安装说明。
这意味着您应该使用另一个包来阅读 .env 文件。 示例在他们的官方网站使用 Dotenv 类将文件的内容加载到环境中：
It is implied that you should use another package for reading the .env files. There is a sample on their official site that uses a Dotenv class to load contents of the files into environment:
<?php
require 'vendor/autoload.php';
Dotenv::load(__DIR__);
$sendgrid_apikey = getenv('YOUR_SENDGRID_APIKEY');
尽管如此，他们甚至没有解释课程来自哪里。显然，这意味着您应该安装 vlucas / phpdotenv 包。请注意，在这个软件包的当前版本中， load 方法是非静态的（实际上在早期版本中是静态的）：
Still, they don't even explain where the class comes from. Apparently, they mean that you should install vlucas/phpdotenv package. Note, that in the current version of this package, the load method is non-static (it actually was static in early versions):
$dotenv = new Dotenv\Dotenv(__DIR__);
$dotenv->load();