php,xml,ups shipping: "Cannot view XML input using XSL..." Where's the bug?

Question

Hey, so I'm deploying a shipping calculator using this function, and I'm getting this error only when I use IE. Firefox does just fine with the shipping calculator. I'm unfamiliar with this error, and google searches tell me that it's a problem with the xml format. Problem is: the XML response from UPS's shipping calculation server shouldn't have this content. So, my question is: where do you think the bug is? I appreciate answers and suggestions of where to check. I'm drawing a blank.

Error when using IE (vrs 8. 7, and 6):

The XML page cannot be displayed Cannot view XML input using XSL style sheet. Please correct the error and then click the Refresh button, or try again later.

---

Incorrect syntax was used in a comment. Error processing resource 'http://mgxvideo.com/mgxcopy-alpha-3/shopping/cart_displa...

<!------------------- main content ------------------------->

----------^

Portion of the php code requesting from the server:

$ch = curl_init("https://www.ups.com/ups.app/xml/Rate");
        curl_setopt($ch, CURLOPT_HEADER, 1);
        curl_setopt($ch,CURLOPT_POST,1);
        curl_setopt($ch,CURLOPT_TIMEOUT, 90);
        curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
        curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, 0);
        curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, 0);
        curl_setopt($ch,CURLOPT_POSTFIELDS,$data);
        $result=curl_exec ($ch);
    echo '<!-- '. $result. ' -->'; // THIS LINE IS FOR DEBUG PURPOSES ONLY-IT WILL SHOW IN HTML COMMENTS
        $data = strstr($result, '<?');
        $xml_parser = xml_parser_create();
        xml_parse_into_struct($xml_parser, $data, $vals, $index);
        xml_parser_free($xml_parser);
        $params = array();
        $level = array();
        foreach ($vals as $xml_elem) {
         if ($xml_elem['type'] == 'open') {
        if (array_key_exists('attributes',$xml_elem)) {
          list($level[$xml_elem['level']],$extra) = array_values($xml_elem['attributes']);
        } else {
          $level[$xml_elem['level']] = $xml_elem['tag'];
        }
         }
         if ($xml_elem['type'] == 'complete') {
        $start_level = 1;
        $php_stmt = '$params';
        while($start_level < $xml_elem['level']) {
          $php_stmt .= '[$level['.$start_level.']]';
          $start_level++;
        }
        $php_stmt .= '[$xml_elem[\'tag\']] = $xml_elem[\'value\'];';
        eval($php_stmt);
         }
        }
        curl_close($ch);
     #print_r($params);
     #echo "<br/><br/>";
        return $params['RATINGSERVICESELECTIONRESPONSE']['RATEDSHIPMENT']['TOTALCHARGES']['MONETARYVALUE'];

And here's what Firefox echoes as the result from the xml request (in the above code, it's the line that says "THIS LINE IS FOR DEBUG PURPOSES ONLY":

<!-- HTTP/1.1 100 Continue

HTTP/1.1 200 OK
Date: Fri, 26 Jun 2009 21:58:04 GMT
Server: Apache
Pragma: no-cache
Content-Length: 1524
Content-Type: application/xml

<?xml version="1.0"?><RatingServiceSelectionResponse><Response><TransactionReference><CustomerContext>Bare Bones Rate Request</CustomerContext><XpciVersion>1.0</XpciVersion></TransactionReference><ResponseStatusCode>1</ResponseStatusCode><ResponseStatusDescription>Success</ResponseStatusDescription></Response><RatedShipment><Service><Code>02</Code></Service><RatedShipmentWarning>Your invoice may vary from the displayed reference rates</RatedShipmentWarning><BillingWeight><UnitOfMeasurement><Code>LBS</Code></UnitOfMeasurement><Weight>6.0</Weight></BillingWeight><TransportationCharges><CurrencyCode>USD</CurrencyCode><MonetaryValue>14.34</MonetaryValue></TransportationCharges><ServiceOptionsCharges><CurrencyCode>USD</CurrencyCode><MonetaryValue>0.00</MonetaryValue></ServiceOptionsCharges><TotalCharges><CurrencyCode>USD</CurrencyCode><MonetaryValue>14.34</MonetaryValue></TotalCharges><GuaranteedDaysToDelivery>2</GuaranteedDaysToDelivery><ScheduledDeliveryTime></ScheduledDeliveryTime><RatedPackage><TransportationCharges><CurrencyCode>USD</CurrencyCode><MonetaryValue>14.34</MonetaryValue></TransportationCharges><ServiceOptionsCharges><CurrencyCode>USD</CurrencyCode><MonetaryValue>0.00</MonetaryValue></ServiceOptionsCharges><TotalCharges><CurrencyCode>USD</CurrencyCode><MonetaryValue>14.34</MonetaryValue></TotalCharges><Weight>6.0</Weight><BillingWeight><UnitOfMeasurement><Code>LBS</Code></UnitOfMeasurement><Weight>6.0</Weight></BillingWeight></RatedPackage></RatedShipment></RatingServiceSelectionResponse> -->

Ideas?

Answer 1

the issue was poor html formatting. I deleted all my comments, and for some reason it's working better now.

Answer 2

Technically, you can't have '--' inside of XML comments. So you should change:

<!------------------- main content ------------------------->

to

<!--                  main content                     -->

...or something similar. If UPS is sending it. You can replace it before you forward it to the browser.

EDIT

Regarding displaying the markup rather than rendered HTML: If you're seeing the same thing as in Firefox (<RatingServiceSelectionResponse, etc.) that's not HTML--it's XML. You'll either want to transform it with XSLT or use XPath (or XQuery, etc.) to fetch particular values out of it. Looks like you could also use the $myRate->getRate() function from ups-php API you referenced.