Php 无法使用curl将动态数据从窗体传递到api

我有一个表单，我希望通过它捕获值，并将其以json格式传递到api中，为此我使用以下代码

<?php
$name = $this->input->post('name');
$location = $this->input->post('location');
$age = $this->input->post('age');

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "https://example.com");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "{
    'name' => $name,
    'location' => $location,
    'age' => $age
}");

curl_setopt($ch, CURLOPT_POST, 1);

$headers = array();
$headers[] = "Apikey: ***";
$headers[] = "Cache-Control: no-cache";
$headers[] = "Content-Type: application/json";
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$result = curl_exec($ch);

$http_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);

print_r($http_status);

echo "<br>";

if (curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
}
curl_close ($ch);

print_r($result);
?>

---

不要发明轮子。传递数据时使用
json\u encode
：

$post_fields = array(
    'name' => $name,
    'location' => $location,
    'age' => $age
);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($post_fields));

我收到此错误：此异常已记录为id 73jbj3e8b。