cURL post data to asp.net page

I am trying to call the __doPostback javascript function in a asp.net page from php using curl.

I learnt that this can be done by making a post request to the asp.net page with the appropriate parameters.

So in curl,

1. I make a get request / just use file_get_contents to retrieve the initial page.
2. From this, I extract the values for __VIEWSTATE and __EVENTVALIDATION.

So far everything seems ok.

Now, I understand that we need to make a post request using cURL with __VIEWSTATE and other parameters required. ( values for the fields present in the asp.net form )

I am unable to construct the CURLOPT_POSTFIELDS correctly.

For instance, I am trying this out,

$postoptions1='__EVENTTARGET='.('ctl00$ContentPlaceHolder1$gRef').'&__EVENTARGUMENT='.('$2');
$postoptions2 =  '&__VIEWSTATE='.urlencode($viewState) ;
$otherparams = '&ctl00$ContentPlaceHolder1$ddlName=Abc';

And before using setopt for CURLOPT_POSTFIELDS, I am doing,

urlencode ($postoptions1.$postoptions2.$otherparams)

This does not work. The submit results are not shown, which means, the required parameter __VIEWSTATE was not found in my post request.

If I change the order of the parameters and place __VIEWSTATE as the first parameter, the results page is shown but the other parameter values are not honoured.

I think there is some problem with the way I am encoding the parameters.

Please tell me how to construct the parameters for the post request to a asp.net page.

Thanks.

–Edited–

Here is the complete code:
$resultsPerPage=’10’;
$url = “www.example.com”; // url changed

$curl_connection = curl_init($url);
function sendCurl($curl_connection,$url,$params,$isPost=false) {

//$post_string = $params;
$post_string = http_build_query($params);
//$post_string = build_query_string($params);
//$post_string = urlencode($params); 

echo 'After Encode'.$post_string;
   $cookie="/cookie.txt";


   //set options
    curl_setopt($curl_connection, CURLOPT_CONNECTTIMEOUT, 300);
    curl_setopt($curl_connection, CURLOPT_USERAGENT, 
      "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)");
    curl_setopt($curl_connection, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl_connection, CURLOPT_HEADER, 0); // don't return headers 

    curl_setopt($curl_connection, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($curl_connection, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($curl_connection,CURLOPT_REFERER, $url);
    if($isPost) {
        curl_setopt ($curl_connection, CURLOPT_POST, true);
        //set data to be posted
        curl_setopt($curl_connection, CURLOPT_POSTFIELDS, $post_string);
        curl_setopt($curl_connection,CURLOPT_COOKIEJAR,$cookie);

    }
    else {
    curl_setopt($curl_connection,CURLOPT_COOKIEFILE,$cookie);
    }
   $response1 = curl_exec($curl_connection);
   if($response1 === false)
    {
        echo 'Curl error: ' . curl_error($curl_connection);
    }
    else
{
    echo 'Operation completed without any errors';
}
   return $response1;
}  **// First time, get request to asp.net page

$response1 = sendCurl($curl_connection,$url,'',false);
$viewState=getVStateContent($response1);
$eventValidation =getEventValidationContent($response1);
$simpleParams = '&__VIEWSTATE='.$viewState.'&ctl00$ContentPlaceHolder1$ddlManuf=&ctl00$ContentPlaceHolder1$ddlCrossType=&ctl00$ContentPlaceHolder1$ddlPageSize='.$resultsPerPage.'&ctl00$ContentPlaceHolder1$btnSearch=Search&ctl00_ToolkitScriptManager1_HiddenField=&__EVENTTARGET=&__EVENTARGUMENT=';
// Second post - for submitting the search form
$response2= sendCurl($curl_connection,$url,$simpleParams,true);
—-**

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

What you want is http_build_query, which will format an array as proper HTTP parameters.

Edit: To clarify what this should probably look like:

$params = array(
    '__EVENTTARGET' => 'ctl00$ContentPlaceHolder1$gRef',
    '__EVENTARGUMENT' => '$2',
    '__VIEWSTATE' => $viewState,
    'ctl00$ContentPlaceHolder1$ddlName' => 'Abc'
);

curl_setopt($curlHandler, CURLOPT_POSTFIELDS, http_build_query($params));

Also, what’s ctl00$ContentPlaceHolder1$ddlName supposed to be?

Method 2

Don’t urlencode() the ampersands (&) linking the parameters together, just the keys & values (the stuff on either side of the ampersands).

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0