如何在函数内传递一个变量？

Question

我正在使用API​​ 并将变量传递给API的函数，但在此情况下它的工作原理如下： curl_init（'https://www.coinpayments.net/api.php?txid=123456'）;

我想通过一个变量传递TxID添加价值，我尽我所能，但上面的功能不受以下方式运行：

$value="https://www.coinpayments.net/api.php?txid=".$txnid; 

     curl_init($value); 

    curl_init('https://www.coinpayments.net/api.php?txid=$txnid'); 
    curl_init('https://www.coinpayments.net/api.php?txid='$txnid''); 
    curl_init("https://www.coinpayments.net/api.php?txid='".$txnid."'"); 
    curl_init("https://www.coinpayments.net/api.php?txid=$txnid"); 

Answer 1

当我使用的浏览器 火上面API URL它显示错误

API requests can only be made via POST. For documentation see: https://www.coinpayments.net/apidoc 

所以你必须使用下面的代码来传递变量作为之后的参数

<?php 

$curl = curl_init(); 

curl_setopt_array($curl, array(
    CURLOPT_URL => "https://www.coinpayments.net/api.php", 
    CURLOPT_RETURNTRANSFER => true, 
    CURLOPT_CUSTOMREQUEST => "POST", 
    CURLOPT_POSTFIELDS => "{'txn_id':".$txn_id."}", 
    CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache", 
    "content-type: application/json" 
), 
)); 

$response = curl_exec($curl); 
$err = curl_error($curl); 

curl_close($curl); 

if ($err) { 
    echo "cURL Error #:" . $err; 
} else { 
    echo $response; 
} 
?> 

我接到了上面的URL响应当我使用上面的代码

{ 
    "error": "No HMAC signature sent", 
    "result": [] 
}