curl_exec($handle) returns nothing

Question

I'm building a simple CRUD API in PHP and Curl and I have an HTML form that sends ID, FName, LName. The form is posted to create.php and then calls ApiHandler.php that set up the Curl request, then send it to read-api.php. The json file is updated with the new user and returns the json file content as a string but $response is an empty string and doesn't contain the json content $response = curl_exec($handle); // $response = ""

ApiHandler.php

<?php
function callAPI($method, $url, $request){
   $handle = curl_init();
   switch ($method){

      case "GET":
         curl_setopt($handle, CURLOPT_CUSTOMREQUEST, 'GET');                        
         curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);    
         break;

      case "PUT":
         curl_setopt($handle, CURLOPT_CUSTOMREQUEST, "PUT");
         if ($request)
            curl_setopt($handle, CURLOPT_POSTFIELDS, $request);                             
         break;

      case "POST":
         curl_setopt($handle, CURLOPT_POST, 1);
         if ($request)
         curl_setopt($handle, CURLOPT_POSTFIELDS, $request);
         break;

       case "DELETE":
         curl_setopt($handle, CURLOPT_CUSTOMREQUEST, "DELETE");  

         default:
         if ($request)
             $handle = sprintf("%s?%s", $url, http_build_query($request));
   }

   curl_setopt($handle, CURLOPT_HTTPHEADER, [
      "Content-Type: application/json; charset=UTF-8",
      "Access-Control-Allow-Origin: *"
      ]);

   curl_setopt($handle, CURLOPT_URL, $url);
   curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);

   $response = curl_exec($handle); // $response = ""??

        $errno = curl_errno($handle);
        $err = curl_error($handle);

  curl_close($handle);

      if ($errno) {
         return "cURL Error #:" . $err;} 
      else {

   return $response;
}


}

function getBaseUrl()
{
   return "http://localhost/api/";
}

?>

This is the api that take the request and supposed to save it to a file and return the json string.

create-api.php

<?php 
include('ApiHandler.php');

header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");


$postData = file_get_contents('php://input');

$data = array();
parse_str($postData, $data);

$json = file_get_contents('employees.json');
$obj = json_decode($postData,true);
$jsonarray = json_decode($json,true);



array_push($jsonarray,$obj);
$result = json_encode($jsonarray);
$file = fopen('employees.json','w');
fwrite($file,$result);
fclose($file);
return $result;

?>

create.php

<?php
include('ApiHandler.php');

$url = getBaseUrl()."create-api.php";

$postdata = file_get_contents("php://input");
$id = $_REQUEST["id"];
$firstname = $_REQUEST["firstname"];
$lastname = $_REQUEST["lastname"];

$arrayRequest = array("id"=>$id,"firstname"=>$firstname,"lastname"=>$lastname);


$json = json_encode($arrayRequest,true);

$output = callAPI("POST", $url, $json);


var_dump($output);

echo ("<p>$output</p>");
?>

Does anyone have any idea why the response is empty?

Try checking for errors - https://stackoverflow.com/questions/3987006/how-to-catch-curl-errors-in-php — Nigel Ren, Apr 04 '20 at 07:01

score 1 · Answer 1 · answered Apr 04 '20 at 12:59

1

Your create-api.php script needs to output something to be caught by curl_exec()

So you need to replace your return $result; (which makes no sense in this context as you are not in a function) by echo $result;

answered Apr 04 '20 at 12:59

Joffrey Schmitz

2,393
3
19
28

score 0 · Answer 2 · answered Apr 04 '20 at 06:51

0

Try to change this line in your code from:

curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);

to this:

curl_setopt($curl, CURLOPT_RETURNTRANSFER, true)

answered Apr 04 '20 at 06:51

Leonidas Menendez

469
9
15

why does this make a difference? OPs code doesn't seem to have a `$curl` var, so please explain where you got this from? – Martin Apr 04 '20 at 13:05

curl_exec($handle) returns nothing

2 Answers2