PHP - Append new JSON object to nested array within JSON object - php

Question

Setup
I have retrieved a JSON string from a URL using 'file_get_contents' and have subsequently decoded it using `json_decode'
$search_URL="http://abcdefg.com"
$json = file_get_contents($search_URL);
$obj = json_decode($json, true);
The JSON represents an Apache Solr search response:
{
"responseHeader":{
"status":0,
"QTime":3,
"params":{
"q":"zzzzzzz",
"wt":"json"
}
},
"response":{
"numFound":20690,
"start":0,
"docs":[
{
"title":"yyyyy-y-y-yyyyy-yy-y",
"author":"author 1, author 2, author 3",
"url":"https://yyyyy.com",
"id":yyyy,
"_version_":yyyyy
},
{
"title":"xxxx-x-x-xxxx-xxxx",
"author":"author 1, author 2",
"url":"https://xxxxx.com",
"id":xxxxx,
"_version_":xxxxxx
},
]
}
}
I basically need to grab each author field in the docs[] array, split it by commas to get a new array
$author_array = explode(", ", $author);
I then need to call another web service with these author names that will return JSON. I would love to simply plug this JSON in to my existing JSON and send it all back
Question
I need to modify my JSON so that each doc contains this new JSON object. How can I do this?
{
"title":"xxxx-x-x-xxxx-xxxx",
"author":"author 1, author 2",
"url":"https://xxxxx.com",
"id":xxxxx,
"_version_":xxxxxx,
"authors":[
{
"name": "author1",
"id": "143"
},
{
"name": "author2",
"id": "72"
}
]
}
My Attempt
I have tried a simpler version of this where I simply have an array of author names
{
"title":"xxxx-x-x-xxxx-xxxx",
"author":"author 1, author 2",
"url":"https://xxxxx.com",
"id":xxxxx,
"_version_":xxxxxx,
"authors":[
"author1",
"author2"
]
}
I tried the following:
$response = $obj['response'];
$docs = $response['docs'];
foreach($docs as &$doc) {
$author = $doc['author'];
$authors_array = explode(" ,", $author);
$doc['authors'] = $authors_array;
}
This has ultimately failed as the new array is not appended.

Answer 1

Explode the author string, call the API on each element, make an array of all these results, and put it back into the object.
I use a reference below in foreach so it can modify the document element directly.
foreach ($obj['response']['docs'] AS &$doc) {
$author_names = explode(',', $doc['author']);
$author_array = array_map('author_api', $author_names);
$doc['authors'] = $author_array;
}