Send header and post in curl to localbitcoins - php

Question

I had tried to send info in a post and a header throw localbitcoins and get one error:
HMAC authentication key and signature was given, but they are invalid
From what i learn with localbitcoins api is this just a code u get when u mess with the header can someone help me to solve why I get this error because don't know whats wrong in my code:
function localbitcoins_query2($path, array $req = Array()) {
$key='mycode';
$secret='mycode';
$mt = explode(' ', microtime());
$nonce = $mt[1].substr($mt[0], 2, 6);
if ($req) {
$get=httpbuildquery($req);
$path=$path.'?'.$get;
}
$postdata=$nonce.$key.$path;
$sign = strtoupper(hash_hmac('sha256', $postdata, $secret));
$headers = array(
'Apiauth-Signature:'.$sign,
'Apiauth-Key:'.$key,
'Apiauth-Nonce:'.$nonce
);
$ch = null;
$ch = curl_init();
$data = array("lat" => "Hagrid", "price_equation" => "36");
$data_string = json_encode($data);
curl_setopt($ch, CURLOPT_URL,"https://localbitcoins.com".$path);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20);
$res = curl_exec($ch);
if ($res === false) throw new Exception('Curl error: '.curl_error($ch));
$dec = json_decode($res, true);
if (!$dec) throw new Exception('Invalid data: '.$res);
curl_close($ch);
return $dec;
}

Answer 1

Try this solution:
function localbitcoins_query2($path, array $req = Array()) {
$key='mycode';
$secret='mycode';
$mt = explode(' ', microtime());
$nonce = $mt[1].substr($mt[0], 2, 6);
$get = "";
if ($req) {
$get=httpbuildquery($req);
}
$postdata=$nonce.$key.$path.$get; // NOTE: $postdata without '?' char before the parameters!;
$sign = strtoupper(hash_hmac('sha256', $postdata, $secret));
$headers = array(
'Apiauth-Signature:'.$sign,
'Apiauth-Key:'.$key,
'Apiauth-Nonce:'.$nonce
);
$ch = null;
$ch = curl_init();
$data = array("lat" => "Hagrid", "price_equation" => "36");
$data_string = json_encode($data);
curl_setopt($ch, CURLOPT_URL,"https://localbitcoins.com".$path.( $get=="" ? "" : "?".$get)); // NOTE: here it's necesary '?' char before the parameters!);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20);
$res = curl_exec($ch);
if ($res === false) throw new Exception('Curl error: '.curl_error($ch));
$dec = json_decode($res, true);
if (!$dec) throw new Exception('Invalid data: '.$res);
curl_close($ch);
return $dec;
}