How to use basic authorization in PHP curl

I am having problem with PHP curl request with basic authorization.

Here is the command line curl:

curl -H "Accept: application/product+xml" "https://{id}:{api_key}@api.domain.com/products?limit=1&offset=0"

I have tried by setting curl header in following ways but it's not working

Authorization: Basic id:api_key
or 
Authorization: Basic {id}:{api_key}

I get the response "authentication parameter in the request are missing or invalid" but I have used proper id and api_key which is working in command line curl (I tested)

Please help me.

Try the following code :

$username='ABC';
$password='XYZ';
$URL='<URL>';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$URL);
curl_setopt($ch, CURLOPT_TIMEOUT, 30); //timeout after 30 seconds
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
curl_setopt($ch, CURLOPT_USERPWD, "$username:$password");
$result=curl_exec ($ch);
$status_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);   //get status code
curl_close ($ch);

Can you try this,

 $ch = curl_init($url);
 ...
 curl_setopt($ch, CURLOPT_USERPWD, $username . ":" . $password);  
 ...

REF: http://php.net/manual/en/function.curl-setopt.php

$headers = array(
    'Authorization: Basic '. base64_encode($username.':'.$password),
);
...
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);