次のプログラムを差し替え

app/Models/Cities.php

<?php
// --------------------------------------------------------------------
/*
	app/Models/Cities.php

					Jun/07/2018

*/
// --------------------------------------------------------------------
namespace App\Models;

use Illuminate\Database\Eloquent\Model;

// --------------------------------------------------------------------
class someclass
{
  var $id = "";
  var $name = "";
  var $population = "";
  var $date_mod = "";
  
  function do_something() {
    echo "メソッド内部から出力";
  }
}

// --------------------------------------------------------------------
class cities extends Model
{
  public function getData()
  {
	$url = storage_path() . '/app/public/data/cities.json';
	$json_string = file_get_contents($url);
	$dict_aa = json_decode ($json_string,true);
	$data = array();
	foreach ($dict_aa as $key => $value)
		{
		$unit_aa = new someclass();
		$unit_aa->id = $key;
		$unit_aa->name = $value["name"];
		$unit_aa->population = $value["population"];
		$unit_aa->date_mod = $value["date_mod"];
		array_push($data,$unit_aa);
		}
	return $data;
  }
}

// --------------------------------------------------------------------

次の JSON を配置

mkdir storage/app/public/data

storage/app/public/data/cities.json

{
  "t0921": {
    "date_mod": "1922-10-8",
    "name": "宇都宮",
    "population": 76381
  },
  "t0922": {
    "date_mod": "1922-8-12",
    "name": "小山",
    "population": 91237
  },
  "t0923": {
    "date_mod": "1922-3-28",
    "name": "佐野",
    "population": 23158
  },
  "t0924": {
    "date_mod": "1922-7-21",
    "name": "足利",
    "population": 51426
  },
  "t0925": {
    "date_mod": "2018-5-29",
    "name": "日光",
    "population": 342
  },
  "t0927": {
    "date_mod": "1922-7-17",
    "name": "さくら",
    "population": 46185
  },
  "t0929": {
    "date_mod": "1922-5-9",
    "name": "真岡",
    "population": 71823
  },
  "t0930": {
    "date_mod": "1922-8-12",
    "name": "栃木",
    "population": 82361
  },
  "t0931": {
    "date_mod": "1922-5-25",
    "name": "大田原",
    "population": 36128
  },
  "t0932": {
    "date_mod": "1922-4-8",
    "name": "鹿沼",
    "population": 19254
  },
  "t0933": {
    "date_mod": "1922-3-17",
    "name": "那須塩原",
    "population": 35682
  },
  "t0934": {
    "date_mod": "1922-2-21",
    "name": "那須烏山",
    "population": 24931
  }
}

他には変更はありません。

サーバーの起動

php artisan serve

ブラウザーでアクセス

http://127.0.0.1:8000/sample/model/

確認したバージョン

$ uname -a
Linux shimizu 6.2.0-32-generic #32-Ubuntu SMP PREEMPT_DYNAMIC Mon Aug 14 10:03:50 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

$ php --version
PHP 8.1.12-1ubuntu4.3 (cli) (built: Aug 17 2023 17:37:48) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.12, Copyright (c) Zend Technologies
    with Zend OPcache v8.1.12-1ubuntu4.3, Copyright (c), by Zend Technologies

$ php artisan --version
Laravel Framework 10.22.0