Get HTML page <input> values and names using regex on PHP

Question

Ok, so as the title says, I have an HTML page that I fetch using libcurl (cURL inside PHP).
That page has one <form> that I need to extract the <input> names and values, and I would like to do that using Regex.
I'm making it using Regex because I think that's the easier way. If you think I shouldn't use regex, but something like xpath, say how.

I don't know if you can understand what I'm trying to say, so feel free to ask.

Here's the PHP code (complete):

<?php



/***** DISABLED BY NETWORK TRAFFIC REASONS... USING LOCAL CACHE

$curl = curl_init();
$url = 'https://secure.optimus.pt/Particulares/Kanguru/Login/';
$useragent = 'Mozilla/5.0 (Windows; U; Windows NT 6.0; pt-PT; rv:1.9.1) Gecko/20090624 Firefox/3.5';
curl_setopt($curl,CURLOPT_URL,$url);
curl_setopt($curl,CURLOPT_USERAGENT,$useragent);
curl_setopt($curl,CURLOPT_SSL_VERIFYPEER,true);
curl_setopt($curl,CURLOPT_SSL_VERIFYHOST,2);
curl_setopt($curl,CURLOPT_CAINFO,getcwd()."\optimus_secure.crt");
curl_setopt($curl,CURLOPT_RETURNTRANSFER,true);
$contents = curl_exec($curl);
*/

$contents = file_get_contents('local_secure.html');
preg_match('%<form name="aspnetForm" .*? action="(.*?)" .*?>(.*?)</form>%s',$contents,$matches);
//echo '<pre>'.htmlentities($contents).'</pre>';
//array_shift($matches);
echo '<pre>---------';
foreach($matches as $match)
    echo '$match:::::: '.htmlentities($match)."\r\n\r\n";
echo '</pre>';

echo '<pre>__________';
preg_match_all('/<input type=".*?" name="(.*?)" value="(.*?)" \/>/', $matches[0], $matches2);
print_r($matches2);
echo '</pre>';

?>

Of course that the <pre> tags and all that output is just for debugging.

Also, here's the source code of the HTML page (the part that matters):

<form name="aspnetForm" method="post" action="../Login?OptimusChannelID=D5774383-A407-42E9-A0AD-4838C97AB162&amp;OptimusContentID=&amp;OptimusSelectedSiteID=B33E7D52-8738-4756-A25D-B907D1823B71&amp;OptimusSelectedAreaID=AF8E0BDF-17E3-4438-9FA9-D53A13A508D8&amp;OptimusSelectedLocalID=D5774383-A407-42E9-A0AD-4838C97AB162" onsubmit="javascript:return WebForm_OnSubmit();" id="aspnetForm">
<div>
<input type="hidden" name="__EVENTTARGET" id="__EVENTTARGET" value="" />
<input type="hidden" name="__EVENTARGUMENT" id="__EVENTARGUMENT" value="" />
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKLTc4MzE4NTQyNQ9kFgJmD2QWBgIID2QWAgIBD2QWBGYPZBYCAgMPDxYEHhRWYWxpZGF0aW9uRXhwcmVzc2lvbgUCLioeB0VuYWJsZWRoZGQCAQ9kFgICBQ8PFgIeBFRleHQFKk8gY2FtcG8gRW1haWwgJmVhY3V0ZTsgb2JyaWdhdCZvYWN1dGU7cmlvIWRkAgkPZBYCAgEPFgIfAmVkAgoPDxYCHgdWaXNpYmxlaGRkGAEFHl9fQ29udHJvbHNSZXF1aXJlUG9zdEJhY2tLZXlfXxYCBSVjdGwwMCRNYWluQ29udGVudFBsYWNlSG9sZGVyJEltZ0xvZ2luBSxjdGwwMCRNYWluQ29udGVudFBsYWNlSG9sZGVyJGltZ0J0blJlY3VwZXJhcorZDETv8JCxlvTojv3w53/dbo9m" />
</div>
<script type="text/javascript">....</script>
<script src="..." type="text/javascript"></script>
<script src="..." type="text/javascript"></script>
<script type="text/javascript">...</script>
<div class="row_container">
<div class="titulo_barra rosa laranja_empresas">
LOGIN<br/>
</div>
<div class="PanelLogin">
<div class="Mensagem">
<div class="texto">
Para aceder, por favor, fa&ccedil;a login. 
</div>
</div>
<div id="ctl00_MainContentPlaceHolder_PanelLogin" onkeypress="javascript:return WebForm_FireDefaultButton(event, 'ctl00_MainContentPlaceHolder_ImgLogin')">
<div class="Mensagem">
<div>                           
<label for="telem">
User<span id="ctl00_MainContentPlaceHolder_UsernameValidator" style="color:Red;display:none;"></span>
</label>
<input name="ctl00$MainContentPlaceHolder$TxtUsername" type="text" id="ctl00_MainContentPlaceHolder_TxtUsername" class="text" maxlength="255" />
<label style="padding-left: 10px" for="password">
Password
<span id="ctl00_MainContentPlaceHolder_RequiredPasswordValidator" style="color:Red;display:none;"></span><span id="ctl00_MainContentPlaceHolder_UsernameRegexValidator" style="color:Red;display:none;"></span> </label>
<input name="ctl00$MainContentPlaceHolder$TxtPassword" type="password" id="ctl00_MainContentPlaceHolder_TxtPassword" class="text" maxlength="5" />
<input type="hidden" name="fromssl" value="" />
<input type="image" name="ctl00$MainContentPlaceHolder$ImgLogin" id="ctl00_MainContentPlaceHolder_ImgLogin" src="/img/btn_password.gif" alt="Login" onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$MainContentPlaceHolder$ImgLogin&quot;, &quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))" style="border-width:0px;position: absolute; padding-left: 5px " /><br />                          
</div>
<div id="login_error_box">
<div id="ctl00_MainContentPlaceHolder_ValidationSummary1" class="error" style="color:#FF6000;display:none;">
</div>
</div>
</div>
</div>
</div>
<div class="titulo_barra rosa laranja_empresas">
RECUPERA&Ccedil;&Atilde;O DE PASSWORD
</div>
<div class="PanelLogin">
<div class="Mensagem">
<div class="texto">
Para recuperar a sua password introduza o seu e-mail. Se pretender recuperar o seu username utilize o link abaixo
</div>
</div>
<div id="ctl00_MainContentPlaceHolder_Panel1" onkeypress="javascript:return WebForm_FireDefaultButton(event, 'ctl00_MainContentPlaceHolder_imgBtnRecuperar')">
<div class="Mensagem">
<div id="Div1">
<label for="telem">
Email</label>
<input name="ctl00$MainContentPlaceHolder$txtEmailHabitual" type="text" id="ctl00_MainContentPlaceHolder_txtEmailHabitual" class="text" maxlength="255" />
<input type="image" name="ctl00$MainContentPlaceHolder$imgBtnRecuperar" id="ctl00_MainContentPlaceHolder_imgBtnRecuperar" class="img rosa azul_empresas" src="/img/bot_recuperar.gif" alt="Recuperar" onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$MainContentPlaceHolder$imgBtnRecuperar&quot;, &quot;&quot;, true, &quot;email&quot;, &quot;&quot;, false, false))" style="border-width:0px;margin-top: -2px; position: absolute;" />
<br />
<span id="ctl00_MainContentPlaceHolder_EmailValidator" class="error" style="color:Red;display:none;">O campo Email &eacute; obrigat&oacute;rio!</span>
<span id="ctl00_MainContentPlaceHolder_EmailRegularExpressionValidator" style="color:Red;display:none;"> Formato do Email inválido.</span>
</div> 
<div class="Mensagem" CssClass="error" DisplayMode="SingleParagraph" ForeColor="#FF6000">
</div>
<a id="ctl00_MainContentPlaceHolder_lnkRecuser" href="javascript:__doPostBack('ctl00$MainContentPlaceHolder$lnkRecuser','')">
<div align="left"  style="color:#FF7000" class="footerButtonsOrange">Recuperar username</div>
</a>
</div>
</div>
</div>
</div>
<script type="text/javascript">...</script>
<script type="text/javascript">...</script>
<script type="text/javascript">...</script>
<div>
<input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWBwKQ08lZAqmxyPwLAvCnm8wMAt/Wt8sGAv2svvMEAtCB5oUIAr6ar9wLz+9apOkY23Vs+vCYNJuK2ug3Gm0=" />
</div>
<script type="text/javascript">...</script>
</form>

Also, sorry for the low readability of the source code. If you want, I can try to indent it better.

Thank you,
Pedro Cunha

EDIT: Thank you all for your help. All the answers worked flawlessly, however I chose VolkerK's response, because since it is an HTML page, elements may be nested, and I know (of the few things that I know about XPath) that // is a wildcard.

Answer 1

If you think I shouldn't use regex, but something like xpath, say how.

That would be something like

<?php
$doc = new DOMDocument;
if ( !$doc->loadhtml($contents) ) {
  echo 'something went wrong';
}
else {
  $xpath = new DOMXpath($doc);
  foreach($xpath->query('//form[@name="aspnetForm"]//input') as $eInput) {
      echo 'name=', $eInput->getAttribute('name'), ' value=', $eInput->getAttribute('value'), "\n";
  }
}

If you get annoying warning messages you might want to use @$doc->loadhtml($contents); maybe in conjuction with libxml_use_internal_errors() and libxml_get_errors()

Answer 2

How about this --> http://simplehtmldom.sourceforge.net/

*  A HTML DOM parser written in PHP5+ let you manipulate HTML in a very easy way!
* Require PHP 5+.
* Supports invalid HTML.
* Find tags on an HTML page with selectors just like jQuery.
* Extract contents from HTML in a single line.

// Create DOM from URL or file
$html = file_get_html('http://www.google.com/');

// Find all images
foreach($html->find('img') as $element)
       echo $element->src . '<br>';

// Find all links
foreach($html->find('a') as $element)
       echo $element->href . '<br>'; 

Good luck.

Answer 3

OK. Since you asked: You should not try to parse non-regular languages with regular expressions. A simple heuristic is: if the language seems "nested", it is not regular.

One simple way might be something along the following lines:

$htmldoc = new DOMDocument;
$htmldoc->loadHTMLFile("local_secure.html");
$forms = $htmldoc->getElementsByTagName("form");
$inputs = $forms->item(0)->getElementsByTagName("input");

foreach ($inputs as $input)
  { do_something_with($input->getAttribute("name"));
    do_something_with($input->getAttribute("value")); };

Add error checks to your liking. Further documentation: http://www.php.net/book.dom