error: charset malformed JSON... this happen with columns fields from db with specials characters... any fix? about api HOT 7 OPEN

        case 'text':
            $d = mb_detect_encoding($v);
            if ($d=='ASCII') { $v=utf8_encode($v); } else { $v=utf8_encode($v); };
            if ($d=='UTF-8') { $v=$v; };
            break;

        case 'text':
       $v=utf8_encode($v);
            break;

<?php
require_once 'vendor/autoload.php';

// Config
$config = [
    'db' => 'mysql://root@localhost/sampledb;charset=utf8',
    'uri' => '.'.$_SERVER['SCRIPT_NAME'],
];
/*
// No need to add character set and collation because these are default settings anyway
CREATE TABLE test_utf8 (
    id int unsigned not null auto_increment,
    desc_en varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci,
    desc_it varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci,
    desc_fr varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci,
    desc_de varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci,
    PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;

this is white cat
questo è gatto bianco
c'est chat blanc
Das ist weiße Katze
*/

// Initialize App
$app = new \atk4\ui\App(['API UTF8 test', 'always_run' => false]); // always_run=false to not render App on shutdown
$app->initLayout('Centered');
$app->init();

// Connect DB
$db = $app->dbConnect($config['db']);

// Header
$app->add(['Header', 'subHeader'=>'https://github.com/atk4/api/issues/8'])
    ->set('Testing utf8');

// Model
class TestModel extends \atk4\data\Model {
    public $table = 'test_utf8';
    public function init() {
        parent::init();
        $this->getElement($this->id_field)->ui['visible'] = true; // to see it in CRUD
        $this->addField('desc_en', ['type' => 'string']);
        $this->addField('desc_it', ['type' => 'string']);
        $this->addField('desc_fr', ['type' => 'string']);
        $this->addField('desc_de', ['type' => 'string']);
    }
}
$m = new TestModel($db);
$m->tryLoadAny();

// CRUD test - works perfectly
$c = $app->add('CRUD');
$c->setModel($m);

// API test
$api = $app->add(new \atk4\api\Api());
$api->rest('/test_utf8', new TestModel($db));

/*
    By default GET converts utf8 entities to \u notation
    See https://stackoverflow.com/a/16498304/1466341
    
    http://localhost/utf8.php/test_utf8/1 returns
{
    "id": "1",
    "desc_en": "this is white cat",
    "desc_it": "questo \u00e8 gatto bianco",
    "desc_fr": "c\u0027est chat blanc",
    "desc_de": "Das ist wei\u00dfe Katze"
}
    If you add JSON_UNESCAPED_UNICODE in Api->successResponse, then it will not convert characters to \u notation,
    but French character ' still will be converted to \u0027 because of this contant JSON_HEX_APOS we have in api.
{
    "id": "1",
    "desc_en": "this is white cat",
    "desc_it": "questo è gatto bianco",
    "desc_fr": "c\u0027est chat blanc",
    "desc_de": "Das ist weiße Katze"
}
*/

$endpoint = $config['uri'].'/test_utf8/';
$c->addModalAction('GET', 'GET request', function($p, $id) use ($m, $endpoint){
    $p->add('Console')->set(function ($console) use ($id, $m, $endpoint, $id) {

        // Make GET request
        $console->debug('Making GET request... ');
        $curl = curl_init();
        curl_setopt_array($curl, [
            CURLOPT_RETURNTRANSFER => 1,
            CURLOPT_URL => $endpoint.$id,
        ]);
        $result = curl_exec($curl);
        curl_close($curl);

        // Response
        $console->debug('Response:');
        $console->output($result);

        // Decode JSON
        $console->debug('Decoded JSON:');
        $data = json_decode($result, true);
        $console->output(var_export($data, true));
        $before = $data;
        
        // Set values in model
        $console->debug('Set received values in model:');
        $m->set($data);
        $fields = $m->get();
        unset($fields['field_sql']); // new bug in atk4/data? what the hell is field_sql ???
        $console->output(var_export($fields, true));
        
        // POST request
        $console->debug('Making POST request...');
        $curl = curl_init();
        curl_setopt_array($curl, [
            CURLOPT_RETURNTRANSFER => 1,
            CURLOPT_URL => $endpoint.$id,
            CURLOPT_POST => 1,
            CURLOPT_POSTFIELDS => $fields,
        ]);
        $result = curl_exec($curl);
        curl_close($curl);

        // Response
        $console->debug('Response:');
        $console->output($result);

        // Make GET request again
        $console->debug('Making GET request again...');
        $curl = curl_init();
        curl_setopt_array($curl, [
            CURLOPT_RETURNTRANSFER => 1,
            CURLOPT_URL => $endpoint.$id,
        ]);
        $result = curl_exec($curl);
        curl_close($curl);

        // Response
        $console->debug('Response:');
        $console->output($result);

        // Decode JSON
        $console->debug('Decoded JSON:');
        $data = json_decode($result, true);
        $console->output(var_export($data, true));
        $after = $data;
        
        // Compare old and new values
        if ($before == $after) {
            $console->info('Old and new values are equal');
        } else {
            $console->error('Old and new values are different');
        }
    });
});

// Render App
// If API URL was called, then we don't go here and App will not be rendered becauseof always_run=false
$app->run();

Making GET request... 
Response:
{
    "id": "1",
    "desc_en": "this is white cat",
    "desc_it": "questo \u00e8 gatto bianco",
    "desc_fr": "c\u0027est chat blanc",
    "desc_de": "Das ist wei\u00dfe Katze"
}
Decoded JSON:
array (
  'id' => '1',
  'desc_en' => 'this is white cat',
  'desc_it' => 'questo è gatto bianco',
  'desc_fr' => 'c\'est chat blanc',
  'desc_de' => 'Das ist weiße Katze',
)
Set received values in model:
array (
  'id' => '1',
  'desc_en' => 'this is white cat',
  'desc_it' => 'questo è gatto bianco',
  'desc_fr' => 'c\'est chat blanc',
  'desc_de' => 'Das ist weiße Katze',
)
Making POST request...
Response:
{
    "id": "1",
    "desc_en": "this is white cat",
    "desc_it": "questo \u00e8 gatto bianco",
    "desc_fr": "c\u0027est chat blanc",
    "desc_de": "Das ist wei\u00dfe Katze"
}
Making GET request again...
Response:
{
    "id": "1",
    "desc_en": "this is white cat",
    "desc_it": "questo \u00e8 gatto bianco",
    "desc_fr": "c\u0027est chat blanc",
    "desc_de": "Das ist wei\u00dfe Katze"
}
Decoded JSON:
array (
  'id' => '1',
  'desc_en' => 'this is white cat',
  'desc_it' => 'questo è gatto bianco',
  'desc_fr' => 'c\'est chat blanc',
  'desc_de' => 'Das ist weiße Katze',
)

Old and new values are equal