PHP CURL调用始终显示NULL

Question

This question has been asked. But any of those didn't work out for me. I am getting NULL when CURL call is made all the time.

The following is my list_clients.php file.

<?php

require_once 'init.php';
header('Content-Type: application/json');
$clientResults  = mysqli_query($link, "SELECT * FROM clients");
$clients        = array();
while($client = mysqli_fetch_assoc($clientResults)){
    $clients[] = $client;
}
echo json_encode($clients);
exit;

So the output of the above is :

[{"ip_address":"192.168.177.137","mac_address":"3a:1a:cf:7c:92:89","added_on":"2017-08-19 12:48:34"},{"ip_address":"192.168.177.137","mac_address":"3a:1a:cf:7c:92:89","added_on":"2017-08-20 08:09:29"}]

The following is my curl_call.php file

<?php
$url    = 'http://127.0.0.1/testing/list_clients.php';
$curl   = curl_init();

curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($curl, CURLOPT_HTTPGET, TRUE);
curl_setopt($curl, CURLOPT_HEADER, 0);
//curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
//curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);
curl_setopt($curl, CURLOPT_HTTPHEADER, array(
                'Content-Type : application/json',
                'Accept: application/json'
        ));
$clientResult   = curl_exec($curl);
if($clientResult == FALSE) {
    var_dump(curl_error($curl));
}
curl_close($curl);

var_dump($clientResult); //For this line I am getting the following image eror

$clients        = json_decode($clientResult, TRUE);

var_dump($clients);

If I var_dump($clientResult); then I am getting the following error

It's displaying NULL all the time. What might be causing the error.

Answer 1

Just now figured out. If I comment the following line of code in the curl_call.php it will work fine.

<?php
$url    = 'http://127.0.0.1/testing/list_clients.php';
$curl   = curl_init();

curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($curl, CURLOPT_HTTPGET, TRUE);
curl_setopt($curl, CURLOPT_HEADER, 0);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);
/* curl_setopt($curl, CURLOPT_HTTPHEADER, array(
                'Content-Type : application/json',
                'Accept: application/json'
        )); */
$clientResult   = curl_exec($curl);
if($clientResult == FALSE) {
    var_dump(curl_error($curl));
}
curl_close($curl);
var_dump($clientResult);
$clients        = json_decode($clientResult);

var_dump($clients);