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[Facebook] Capcha retrieval and response submit

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This does not solve the captcha issue but allows the viewer to manually
solve the captcha by displaying a form and using the response from the
viewer. Maybe a first step to automated captcha solving?

This process relies on the use of a PHP session for storing captcha
details so that the user cannot submit anything else than the response
to the captcha. Response is filtered before being forwarded, also. Once
captcha is solved we get a page ready to be parsed, as usual.

Combined to some kind of OCR, this could automatically solve the
captcha, but currently if only automates the process of retrieving the
challenge and submitting the response.
This commit is contained in:
ORelio 2016-01-23 21:53:23 +01:00
parent 1e998ab6dd
commit d16d514736
1 changed files with 76 additions and 12 deletions
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88
bridges/FacebookBridge.php
View file

@ -5,7 +5,7 @@ class FacebookBridge extends BridgeAbstract{
$this->maintainer = "teromene";
$this->name = "Facebook";
$this->uri = "http://facebook.com/";
$this->uri = "http://www.facebook.com/";
$this->description = "Input a page title or a profile log. For a profile log, please insert the parameter as follow : myExamplePage/132621766841117";
$this->update = "23/10/2015";
@ -19,7 +19,7 @@ class FacebookBridge extends BridgeAbstract{
]';
}
public function collectData(array $param){
public function collectData(array $param) {
//Extract a string using start and end delimiters
function ExtractFromDelimiters($string, $start, $end) {
@ -35,7 +35,7 @@ class FacebookBridge extends BridgeAbstract{
if (is_array($matches) && count($matches) > 1) {
$link = $matches[1];
if (strpos($link, '/') === 0)
$link = 'https://facebook.com'.$link.'"';
$link = 'https://www.facebook.com'.$link.'"';
if (strpos($link, 'facebook.com/l.php?u=') !== false)
$link = urldecode(ExtractFromDelimiters($link, 'facebook.com/l.php?u=', '&'));
return ' href="'.$link.'"';
@ -75,18 +75,77 @@ class FacebookBridge extends BridgeAbstract{
return $matches[0];
};
$html = '';
$html = null;
if(isset($param['u'])) {
if(!strpos($param['u'], "/")) {
$html = file_get_html('https://facebook.com/'.urlencode($param['u']).'?_fb_noscript=1') or $this->returnError('No results for this query.', 404);
} else {
$html = file_get_html('https://facebook.com/pages/'.$param['u'].'?_fb_noscript=1') or $this->returnError('No results for this query.', 404);
//Handle captcha response sent by the viewer
if (isset($_POST['captcha_response']))
{
if (session_status() == PHP_SESSION_NONE)
session_start();
if (isset($_SESSION['captcha_fields'], $_SESSION['captcha_action']))
{
$captcha_action = $_SESSION['captcha_action'];
$captcha_fields = $_SESSION['captcha_fields'];
$captcha_fields['captcha_response'] = preg_replace("/[^a-zA-Z0-9]+/", "", $_POST['captcha_response']);
$http_options = array(
'http' => array(
'method' => 'POST',
'user_agent'=> ini_get('user_agent'),
'header'=>array("Content-type: application/x-www-form-urlencoded\r\nReferer: $captcha_action\r\nCookie: noscript=1\r\n"),
'content' => http_build_query($captcha_fields),
),
);
$context = stream_context_create($http_options);
$html = file_get_contents($captcha_action, false, $context);
if ($html === FALSE) { $this->returnError('Failed to submit captcha response back to Facebook', 500); }
unset($_SESSION['captcha_fields']);
$html = str_get_html($html);
}
} else {
$this->returnError('You must specify a Facebook username.', 400);
unset($_SESSION['captcha_fields']);
unset($_SESSION['captcha_action']);
}
//Retrieve page contents
if (is_null($html)) {
if (isset($param['u'])) {
if (!strpos($param['u'], "/")) {
$html = file_get_html('https://www.facebook.com/'.urlencode($param['u']).'?_fb_noscript=1') or $this->returnError('No results for this query.', 404);
} else {
$html = file_get_html('https://www.facebook.com/pages/'.$param['u'].'?_fb_noscript=1') or $this->returnError('No results for this query.', 404);
}
} else {
$this->returnError('You must specify a Facebook username.', 400);
}
}
//Handle captcha form?
$captcha = $html->find('div.captcha_interstitial', 0);
if (!is_null($captcha))
{
//Save form for submitting after getting captcha response
if (session_status() == PHP_SESSION_NONE)
session_start();
$captcha_fields = array();
foreach ($captcha->find('input, button') as $input)
$captcha_fields[$input->name] = $input->value;
$_SESSION['captcha_fields'] = $captcha_fields;
$_SESSION['captcha_action'] = 'https://www.facebook.com'.$captcha->find('form', 0)->action;
//Show captcha filling form to the viewer, proxying the captcha image
$img = base64_encode(file_get_contents($captcha->find('img', 0)->src));
header('HTTP/1.1 500 '.Http::getMessageForCode(500));
header('Content-Type: text/html');
die('<form method="post" action="?'.$_SERVER['QUERY_STRING'].'">'
.'<h2>Facebook captcha challenge</h2>'
.'<p>Unfortunately, rss-bridge cannot fetch the requested page.<br />'
.'Facebook wants rss-bridge to resolve the following captcha:</p>'
.'<p><img src="data:image/png;base64,'.$img.'" /></p>'
.'<p><b>Response:</b> <input name="captcha_response" placeholder="please fill in" />'
.'<input type="submit" value="Submit!" /></p>'
.'</form>');
}
//No captcha? We can carry on retrieving page contents :)
$element = $html->find('[id^=PagePostsSectionPagelet-]')[0]->children(0)->children(0);
if(isset($element)) {
@ -144,7 +203,7 @@ class FacebookBridge extends BridgeAbstract{
$thumbnail = $profilePic;
//Build and add final item
$item->uri = 'https://facebook.com'.str_replace('&amp;', '&', $post->find('abbr')[0]->parent()->getAttribute('href'));
$item->uri = 'https://facebook.com'.$post->find('abbr')[0]->parent()->getAttribute('href');
$item->thumbnailUri = $thumbnail;
$item->content = $content;
$item->title = $title;
@ -154,7 +213,12 @@ class FacebookBridge extends BridgeAbstract{
}
}
}
}
public function setDatas(array $param){
if (isset($param['captcha_response']))
unset($param['captcha_response']);
parent::setDatas($param);
}
public function getName() {