Storing multiple artist info from API into file (PHP) - php

Question

I really need help. I'm using an API to gather artist information depending on the artist name ($artist_name = $_GET['artistname']).
I need to add the API results into an array and store it into a file (NOT a database). This file will be ever growing as more and more artist entries are added to it.
Once I have an array in the file, I need to be able to read it and parse it. That way I can display the information without repeatedly using the API.
I have figured out how to add an array to a file with one entry, but how can I add more keys into the same array?
This is what I'm using now...
//ARRAY
$artist_info_location_array = array($artist_name => $location_entry);
//FILE
$artist_location_file = get_template_directory()."/Database/Artists/info-location.json";
//GET ARRAY FILE
$get_location_array[] = json_decode(file_get_contents($artist_location_file), true);
if (is_array($get_location_array)) {
if (!array_key_exists($artist_name, $get_location_array)) {
file_put_contents($artist_location_file, json_encode($artist_info_location_array));
}
}
It prints this to the file:
{"Imagine Dragons":"Las Vegas, NV, US"}
That's cool, but I need to be able to add more artists to this SAME ARRAY. So the result should look like this with another artist added:
{"Imagine Dragons":"Las Vegas, NV, US", "Adele":"London, UK"}
That shows Imagine Dragons and Adele both added to the same array.
Can someone help me "append" or add extra keys and values to the same array as they are added to the file?
Thanks.
EDIT 1 (In response to Martin):
I have a panel on the side of the page in question. This panel will show relevant information about the artist that has been searched for. Let's say you search for the artist "Adele". $artist_name would = Adele.
Lets say I'd like to store all artist locations, I would use the example I posted to store each artist location in the file called info-location.json ($artist_location_file).
So every time an artist page is loaded, the artist name and location would be added to the array in the file.
If my example doesn't make any sense, please show me an example on how to add multiple entries into ONE ARRAY. I am using an API and would like to cache this information to use instead of requesting the API on each load.
Hope this makes sense. :)

Answer 1

I might be misunderstanding your question, but if you just want to read in a json file, add an associative array key to it if it does not exist and then put it back into the json file why dont you do something like this:
if (is_array($get_location_array)) {
if (!array_key_exists($artist_name, $get_location_array)) {
$get_location_array[$artist_name] = $location;
file_put_contents($artist_location_file, json_encode($artist_info_location_array));
}
}
file_put_contents will overwrite an existing file (pretty sure). But your best option is to use a database. If you can't do that, then I suggest to prevent writing to the file while you are doing this I suggest you use fopen, flock, and fwrite and then fclose