cURL operation and PHP - php

Question

I have a frontend code
$ch = curl_init();
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
//curl_setopt($ch, CURLOPT_HTTPHEADER, array('Accept: application/json'));
curl_setopt($ch, CURLOPT_URL, $url);
//make the request
$responseJSON = curl_exec($ch);
$response_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if ($response_status == 200) { // success
// remove any "problematic" characters from the json string and then decode
if (debug) {
echo "----finish API of getAPI inside basic_function with status==200---";
echo "<br>";
echo "-------the json response is-------" ; //.$responseJSON;
var_dump($responseJSON);
//print_r($responseJSON);
echo "<br>";
}
return json_decode( preg_replace( '/[\x00-\x1F\x80-\xFF]/', '', $responseJSON ) );
}
and I have a backend code which executed when cURL fired its operation with its URL. The backend code would therefore activated. So, I know cURL is operating.
$output=array (
'status'=>'OK',
'data'=>'12345'
)
$output=json_encode($output)
echo $output;
and $output shown on browser as {"status":"OK","data":"12345"}
However, I gone back to the frontend code and did echo $responseJSON, I got nothing. I thought the output of {"status":"OK","data":"12345"} would gone to the $responseJSON. any idea?
Here's output on Browser, something is very odd! the response_status got 200 which is success even before the parsing of API by the backend code. I expect status =200 and json response after the {"status":"OK","data":"12345"}
=========================================================================================
inside the get API of the basic functions
-------url of cURL is -----http://localhost/test/api/session/login/?device_duid=website&UserName=joe&Password=1234&Submit=Submit
----finish API of getAPI inside basic_function with status==200---
-------the json response is-------string(1153)
"************inside Backend API.php******************
---command of api is--/session/login/
---first element of api is--UserName=joe
--second element of api is---Password=1234
---third element of api is----Submit=Submit
----fourth element of api is---
-------inside session login of api-------------
{"status":"OK","data":"12345"}

Answer 1

Have you tried with curl_setopt($ch, CURLOPT_TIMEOUT, 10); commented?
See what happends if you comment that line.
Also try with the a basic code, if that works, smthing you added later is wrong:
// create a new cURL resource
$ch = curl_init();
// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch, CURLOPT_HEADER, false);
// grab URL and pass it to the browser
curl_exec($ch);
// close cURL resource, and free up system resources
curl_close($ch);

Answer 2

Try var_dump($responseJSON)
If it returns false try
curl_error ( $ch )
Returns a clear text error message for the last cURL operation.
Are you sure your $url is correct?