Lumen controller "talking" to TensorFlow Serving REST API

TensorController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class TensorController extends Controller
{
    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        //
    }


    public function showForm()
    {
        return view('form');
    }


    public function checkImage(Request $request) {

        if (!$request->hasFile('image')) {
            return 'No image uploaded';
        }

        $imageFile = $request->file('image');

        // resize image unproportionally to 380x380
        list($width, $height) = getimagesize($imageFile);

        $src = imagecreatefromjpeg($imageFile);
        $dst = imagecreatetruecolor(380, 380);
        imagecopyresampled($dst, $src, 0, 0, 0, 0, 380, 380, $width, $height);

        unlink($imageFile);

        // convert to JSON array
        $json = '{"inputs":[[';
        for ($y = 0; $y < 380; $y++) {
            $json .= '[';
            for ($x = 0; $x < 380; $x++) {
                $rgb = imagecolorat($dst, $x, $y);
                $r = (($rgb >> 16) & 0xFF) / 0xFF;
                $g = (($rgb >> 8) & 0xFF) / 0xFF;
                $b = ($rgb & 0xFF) / 0xFF;
                $json .= sprintf('[%06f,%06f,%06f]', $r, $g, $b);
                if ($x < 380 - 1) $json .= ',';
            }
            $json .= ']';
            if ($y < 380 - 1) $json .= ',';
        }
        $json .= ']]}';

        // return $json;

        // query TensorFlow Serving
        $ch = curl_init('http://tensorflow:8501/v1/models/orbit:predict');
        curl_setopt_array ($ch, [
            CURLOPT_POST => TRUE,
            CURLOPT_RETURNTRANSFER => TRUE,
            CURLOPT_CONNECTTIMEOUT => 2, // TODO: handle timeout error
            CURLOPT_TIMEOUT => 20,       // TODO: handle timeout error
            CURLOPT_POSTFIELDS => $json,
        ]);

        $response = curl_exec($ch);

        $result = json_decode($response);
        if (!$result) return 'Response JSON decode error: ' . $response;

        if (isset($result->error)) return 'Error: ' . $response;

        // { "outputs": [ [ 0.114583552, 0.104765795, 0.778343379, 0.00230731 ] ] }
        if (isset($result->outputs, $result->outputs[0])) {

            $weights = $result->outputs[0];

            $maxValue = max($weights);
            $maxIndex = array_search($maxValue, $weights);

            if ($maxValue < 0.9) $maxIndex = 2; // "not"
            
            $names_dict = ['bank_pack', 'mega_pack', 'not', 'standart_pack'];

            return $names_dict[$maxIndex];


        } else {
            return 'No outputs in the response: ' . $response;
        }


        return $result;

        return 'OK';

    }
}