How to create/write code in text/json file and get content of file in PHP | Codeigniter

Create file and directory

public function createfileanddir() {
    $directoryname = 'directoryname';
    $filename = 1;
    $directory = APPPATH . 'uploads/cache/'.$directoryname;
    if (!file_exists($directory)) {
        mkdir($directory, 0777, true);
    }
    $file = APPPATH . 'uploads/cache/'.$directoryname.'/'.$filename.'.json';
    if (file_exists($file)) {
        unlink($file);
    }
    if (!file_exists($file)) {
        $settings = [
            'settings'=>[],
            'socialSettingsArr'=>[],
            'pageSettings'=>[],
        ];
        $fh = fopen($file, 'w');
        fwrite($fh, json_encode($settings));
        fclose($fh);
    }
}

Get content from file and directory

public function getfiles() {
    $directoryname = 'directoryname';
    $directory = 'uploads/cache/'.$directoryname;
    $files = array_diff(scandir($directory), array('.', '..'));
    if(count($files) > 0){
        foreach ($files as $file):
            $file = $directory . '/'.$file;
            $storedata = file_get_contents($file);
            $storedata = json_decode($storedata, true);
            echo '<pre>';print_r($storedata);
        endforeach;
    }
}

SQLSTATE[HY000]: General error: 1 Can't create/write to file '/tmp/#sql_83d_0.MYI' (Errcode: 28) Magento / PHP

Problem can be connected with inodes. Maybe you have too many small files and your inodes are full. You can check inode status with df -i