Form submission to google form using CURL

I wrote the following code but then it's submitted Internal error appears. I have no ideas on what is going wrong.

<?php

//extract data from the post
//extract($_GET) ;
//set POST variables

//The form https://spreadsheets.google.com/viewform?authkey=CJPbtZkI&hl=en&formkey=dEd5UFhRQ1ZfNzcwU1UwOVhIbF92cGc6MQ&ifq
$url = 'https://spreadsheets.google.com/formResponse?authkey=CJPbtZkI&amp;hl=en&amp;formkey=dEd5UFhRQ1ZfNzcwU1UwOVhIbF92cGc6MQ&amp;ifq' ;
$fields = array(
'pageNumber'=>urlencode("0" ) ,
'backupCache'=>urlencode("") ,
'submit'=>urlencode("Submit"),
'entry.0.single'=>urlencode("") ,
'entry.1.single'=>urlencode("") ,
'entry.2.single'=>urlencode("") ,
'entry.3.single'=>urlencode("") ,
'entry.4.single'=>urlencode("") ,
'entry.5.single'=>urlencode("") ,
'entry.6.single'=>urlencode("") ,
'entry.7.single'=>urlencode("") ,
'entry.8.single'=>urlencode("") ,
'entry.9.single'=>urlencode("") ,
'entry.10.single'=>urlencode("") ,
'entry.11.single'=>urlencode(""),
'entry.12.single'=>urlencode("")
);
//url-ify the data for the POST
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&' ; }
rtrim($fields_string ,'&') ;
//open connect开发者_高级运维ion
$ch = curl_init() ; 
//set the url, number of POST vars, POST data
curl_setopt($ch, CURLOPT_URL,$url) ;
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: text/xml','Accept-Charset: UTF-8')); 
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,$fields_string) ;
//execute post
$result = curl_exec($ch) ;
print_r($fields_string);
//close connection
curl_close($ch) ;

?>

The obvious first problem is that the URL you are trying to use is HTML encoded (e.g. it has & for &)

Try to add that :

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

Picky point, but your $field_strings variable still has the trailing ampersand. You'd need to do:

$fields_string = rtrim($fields_string ,'&') ;