btcmarkets.php

<?php

namespace App\Helpers;

/*
| BTCMarkets
| Exchange is in AUD.
|
| https://github.com/BTCMarkets/API/wiki/Introduction
|
*/

class BTCMarkets {

    private $key;   
    private $secret;
    private $url;

    function __construct()
    {
        $this->key = env('BTCM_KEY');
        $this->secret = env('BTCM_SECRET');
        $this->url = 'https://api.btcmarkets.net';
    }

    public function history($count = 10, $since)
    {
        $response = $this->request('/order/history', [
            'currency' => 'AUD',
            'instrument' => 'BTC',
            'limit' => $count,
            'since' => $since,
        ]);

        if ($response['success']) {
            return $response;
        }
    }
    
    private function request($method, $data = [])
    {
        $data = json_encode($data);
        $nonce = floor(microtime(true) * 1000); // API requires timestamp in milliseconds

        // build query string
        $tosign = implode('\n', [$method, $nonce, $data]);

        // sign query string
        $signed = base64_encode(hash_hmac('sha512', $tosign, base64_decode($this->secret, true)));

        // generate the extra headers
        $headers = [
            "Accept: application/json",
            "Accept-Charset: UTF-8",
            "Content-Type: application/json",
            "apikey: " . $this->key,
            "signature: " . $signed,
            "timestamp: " . $nonce,
        ];

        // our curl handle (initialize if required)
        static $ch = null;
        if (is_null($ch)) {
            $ch = curl_init();
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; BTC Markets Client; '.php_uname('s').'; PHP/'.phpversion().')');
        }                
     
        curl_setopt($ch, CURLOPT_URL, $this->url . $method);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);

        $response = curl_exec($ch);                
      

        if ($response === false)  {
            return false;
        }
        
        $result = json_decode($response, true);

        if (!$result) {
            return false;   
        }                
        
        return $result;
    }
}

Removed Log class for clarity.