title: curl_setopt cacert.pem for paypal
body: <p>I'm trying to set up a callback handler for IPN (paypal) verification. I know what curl does, but I don't know what 'cacert.pem' is (certificate...?).</p>
  
  <p>this is where the callback.php file fails (exists):</p>
  
  <pre><code>curl_setopt($ch, CURLOPT_CAINFO, 'cacert.pem');
  if( !($res = curl_exec($ch)) ) {
      echo ("Got " . curl_error($ch) . " when processing IPN data");
      curl_close($ch);
      exit;
  }
  curl_close($ch);
  </code></pre>
  
  <p>With the following error message:</p>
  
  <blockquote>
    <p>Got error setting certificate verify locations: CAfile: cacert.pem
    CApath: none when processing IPN data</p>
  </blockquote>
  
  <p>So I downloaded cacert.pem and copied to the directory where the callback.php file is.</p>
  
  <p>This is a comment before the code above:</p>
  
  <pre><code>// In wamp like environments that do not come bundled with root authority certificates,
  // please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path 
  // of the certificate as shown below.
  </code></pre>
  
  <p>I'm using XAMPP, this would be the problem?</p>
  
  <p>And finally this is the whole php file directly from developer page:
  <a href="https://www.x.com/developers/PayPal/documentation-tools/code-sample/216623" rel="nofollow">https://www.x.com/developers/PayPal/documentation-tools/code-sample/216623</a></p>
  
  <pre><code>&lt;?php
  
  // STEP 1: Read POST data
  
  // reading posted data from directly from $_POST causes serialization 
  // issues with array data in POST
  // reading raw POST data from input stream instead. 
  $raw_post_data = file_get_contents('php://input');
  $raw_post_array = explode('&amp;', $raw_post_data);
  $myPost = array();
  foreach ($raw_post_array as $keyval) {
    $keyval = explode ('=', $keyval);
    if (count($keyval) == 2)
       $myPost[$keyval[0]] = urldecode($keyval[1]);
  }
  // read the post from PayPal system and add 'cmd'
  $req = 'cmd=_notify-validate';
  if(function_exists('get_magic_quotes_gpc')) {
     $get_magic_quotes_exists = true;
  } 
  foreach ($myPost as $key =&gt; $value) {        
     if($get_magic_quotes_exists == true &amp;&amp; get_magic_quotes_gpc() == 1) { 
          $value = urlencode(stripslashes($value)); 
     } else {
          $value = urlencode($value);
     }
     $req .= "&amp;$key=$value";
  }
  
  
  // STEP 2: Post IPN data back to paypal to validate
  
  $ch = curl_init('https://www.sandbox.paypal.com/cgi-bin/webscr');
  curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
  curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
  
  // In wamp like environments that do not come bundled with root authority certificates,
  // please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path 
  // of the certificate as shown below.
  curl_setopt($ch, CURLOPT_CAINFO, 'cacert.pem');
  if( !($res = curl_exec($ch)) ) {
      echo ("Got " . curl_error($ch) . " when processing IPN data");
      curl_close($ch);
      exit;
  }
  curl_close($ch);
  
  // STEP 3: Inspect IPN validation result and act accordingly
  
  if (strcmp ($res, "VERIFIED") == 0) {
      // check whether the payment_status is Completed
      // check that txn_id has not been previously processed
      // check that receiver_email is your Primary PayPal email
      // check that payment_amount/payment_currency are correct
      // process payment
  
      // assign posted variables to local variables
      $item_name = $_POST['item_name'];
      $item_number = $_POST['item_number'];
      $payment_status = $_POST['payment_status'];
      $payment_amount = $_POST['mc_gross'];
      $payment_currency = $_POST['mc_currency'];
      $txn_id = $_POST['txn_id'];
      $receiver_email = $_POST['receiver_email'];
      $payer_email = $_POST['payer_email'];
  
      $string = "------------------------\r\n";
      $string .= "item_name: ".$item_name."\r\n";
      $string .= "item_number: ".$item_number."\r\n";
      $string .= "payment_status: ".$payment_status."\r\n";
      $string .= "payment_amount: ".$payment_amount."\r\n";
      $string .= "payment_currency: ".$payment_currency."\r\n";
      $string .= "txn_id: ".$txn_id."\r\n";
      $string .= "receiver_email: ".$receiver_email."\r\n";
      $string .= "payer_email: ".$payer_email."\r\n";
  
      $fp = fopen('test.log', 'w');
      fwrite($fp, $string."\r\n");
      fclose($fp);
  
  } else if (strcmp ($res, "INVALID") == 0) {
      // log for manual investigation
  }
  ?&gt;
  </code></pre>