使用PHP CURL调用self Restful API永远挂起

I want to write a script to call one of my Restful APIs every one hour.

I use Laravel framework.

Here are the codes:

TestController.php

class TestController extends BaseController
{
    public function __construct(ItemCriteria $itemCriteria)
    {
        parent::__construct($itemCriteria);
    }

    public function sayHi()
    {
        echo 'hi';
    }

    public function getHi()
    {
        $ch = curl_init();

        curl_setopt($ch, CURLOPT_URL, "http://127.0.0.1:8888/api/v1/sayhi");

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

        $output = curl_exec($ch);

        curl_close($ch);

        echo $output;
    }

 }

routes.php:

Route::group(array('prefix' => 'api/v1'), function () {
    Route::get('sayhi', 'Api\TestController@sayHi');
    Route::get('gethi', 'Api\TestController@getHi');
}

I call api/v1/gethi, but the response never comes back. Browse just shows loading.

What I have tried:

Searched on Google, many people say this is due to the session being locked. Therefore, I add the code to close session before curl_exec:

public function getHi()
{
    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, "http://127.0.0.1:8888/api/v1/sayhi");

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

    session_write_close();

    $output = curl_exec($ch);

    curl_close($ch);

    echo $output;

}

Sadly, this does not work. I check phpinfo(), sessions should not start automatically as per my settings: session.auto_start Off.

I also did a small experiment: made an API api/vi/sleep, which forces the thread to sleep for 10 seconds. During this time I call api/v1/sayhi, I found it won't respond until first call is finished.

public function sleep()
{
    sleep(10);
}

I thought this might be Apache thread configuration problem, but all configurations seem fine:

<IfModule mpm_winnt_module>
    ThreadsPerChild        150
    MaxConnectionsPerChild   0
</IfModule>

My environment:

• Windows 7 64bit.
• Xampp (Apache 2.4.16; PHP 5.6.12).

I am stuck with this for a few weeks. I don't know that else I can do...