Use Symfony to execute lm_sensors and return a json response.

GetCPUTemps.php

<?php

namespace App;

use Symfony\Component\Process\Process;
use Symfony\Component\Process\Exception\ProcessFailedException;

class GetCPUTemps
{
    public function getTemps(){

        $process = new Process('sensors');
        $process->run();
        if (!$process->isSuccessful()) {
            return 'fail';
        }
        $sensors_out = $process->getOutput();
        preg_match_all("/Core\s(?<Core>\N):\s+\+(?<Current>\N+)\s(?<Format>\w)\s+\(high\s=\s\+(?<Warn>\N+)\s\w,\scrit\s=\s\+(?<Crit>\N{5})\s\w/", $sensors_out, $matches);
        
        for ($i = 0; $i < count($matches['Core']); $i++) {
            $arrOut[$i] = ['core_'.$i => $matches['Current'][$i] ] ;
        }
        return json_encode((['Warn' => $matches['Warn'][0],
                             'Crit' => $matches['Crit'][0],
                             'Temps' => $arrOut, 
                             ]));
    }
}

Example output:

{ Warn: "89.0", Crit: "105.0", Temps: [ { core_0: "35.0" }, { core_1: "28.0" } ] }