如何使用邮政编码获得英国地区？

Question

I want to get the UK region based on the postcode given using PHP. I have written as $ch = curl_init();

$post="PR3 0SG";

curl_setopt($ch,CURLOPT_URL,  "https://api.postcodes.io/postcodes/$post");

curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);

curl_setopt($ch, CURLOPT_POST, TRUE);

//curl_setopt($ch, CURLOPT_POSTFIELDS, "limit=1");

$buffer = curl_exec($ch);

if(empty ($buffer))
{ 
   echo " buffer is empty "; 
}
else
{ 
   echo $buffer; 
}

curl_close($ch); 

I get "buffer is empty" message. What's wrong with this! Is there any other way or script to get UK regions using postcode? I possible please provide.