How to load a file into a variable only once

How to load a file into a variable only once
The application scenario is this:
I have a CSV file that contains some key-value mapping relationships, which are generally invariant.
Several different interfaces need to use the data in this file, so I want to load it all at once, and the other interface calls.

I use singleton mode and the _globals cannot guarantee the load once, every time the refresh interface is load once.

How do I handle it?
------Solution--------------------
PHP is a short connection, one-time loading and then reading bad do
------Solution--------------------
It's best to post the code to see.
------Solution--------------------
Because each request is a separate process, "normal variables" cannot be shared. You can place data in a place that can be accessed uniformly:
1. In the file (not your original file). Hehe, can actually be saved into a K-v array, do not have to read the CSV file every time
In 2.session.
3. In-Memory (reference memcached, Redis and other memory cache principles, KV common storage)
4. In the database.
5. Other storage that can be shared.
The key is not the load once. It is the performance of load.

