I posted in the past about scraping forms for use when you need to make a post using CURL along with a little bit of code. I’ve recently moved on to using DOM and this little function I wrote below. I finally got fed up with sites adding new hidden fields and having to write preg_matches for unique variables that a lot of sites are stuffing into their forms these days to prevent spammers and/or track sessions. 

/*

If you don’t have the plugin already in you need the php-xml plugin. Depending on your setup ‘yum install php-xml’ should do the trick.

$html is the html code of the site you’d get using file_get_contents, CURL or whatever.

$form_number is the number of the form you want - 1. It’s usually ok just to leave this at 0 but sometimes sites have more than 1 form on the page so you have to specify. 

The postData array is returned and ready for posting in CURL, all you need to do is find the few fields you actually need to specify and update those fields within the postData array. It’s usually as easy as $postData['email'] = myemail@emailme.com;

Last note, since this is fairly new, it only works on inputs and textareas. I haven’t ran across needing it for anything else yet, but if you post a comment about something it’s missing I’ll add it for ya.

*/

function getInputs($html, $form_number = 0){
$dom = new DOMDocument();
@$dom->loadHTML($html); //@ is there cuz this will throw up a bunch of errors if the html code isn’t perfect
$forms = $dom->getElementsByTagName(”form”);
$form = $forms->item($form_number);
$inputs = $form->getElementsByTagName(”input”);
foreach($inputs as $input){
$postData[$input->getAttribute('name')] = $input->getAttribute(’value’);
}

$inputs = $form->getElementsByTagName(”textarea”);
foreach($inputs as $input){
$postData[$input->getAttribute('name')] = $input->nodeValue;
}

return $postData;
}

One thing I’ve spent a lot of time over is breaking up post variables for use in CURL and posting to forms. Sure you have the option of using an array or just replacing a few variables in a string with CURL but sometimes forms can get crazy with the amount of unique variables they have. Missing a simple unique variable or spelling it wrong can result in hours of wasted time trying to figure out why something won’t work. So I created this lil snippet of code to basically help break down a post string into a nice postData array for use in CURL.

function formInfo($text){
$forms = split(”&”, $text);

foreach($forms as &$form){

$values = split(”=”, $form);

$check = urldecode($values[1]);

echo ‘$postData[\'' . urldecode($values[0]) . ‘\’]’ . ” = ‘$check’;\n”;
}

}

So for a random example use, I did it on wordpress’s login system.

$text = “log=exosus&pwd=sexytime&rememberme=forever&testcookie=1&redirect_to=http%3A%2F%2Fwordpress.com%2F&submit=Login”;

formInfo($text);

which produces the result:

$postData['log'] = ‘exosus’;
$postData['pwd'] = ’sexytime’;
$postData['rememberme'] = ‘forever’;
$postData['testcookie'] = ‘1′;
$postData['redirect_to'] = ‘http://wordpress.com/’;
$postData['submit'] = ‘Login’;