用php操作dom来抓取数据

Question

I am currently trying to manipulate dom throuhg php to extract views from an fb video page. The below code was working until a bit ago. However now it doesnt find the node that contains the views count. This information is inside a div with id fbPhotoPageMediaInfo . What would be the best way to manipulate the dom through php to get views of an fb video page?

private function _callCurl($url)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Linux; Android 5.0.1; SAMSUNG-SGH-I337 Build/LRX22C; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/42.0.2311.138 Mobile Safari/537.36');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20);
    curl_setopt($ch, CURLOPT_URL, $url);
    $response = curl_exec($ch);
    $http     = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    return array(
        $http,
        $response,
    );
}



function test()
{

    $url     = "https://www.facebook.com/TaylorSwift/videos/10153665021155369/";
    $request = callCurl($url);
    if ($request[0] == 200) {
        $dom = new DOMDocument();
        @$dom->loadHTML($request[1]);
        $elm = $dom->getElementById('fbPhotoPageMediaInfo');
        if (isset($elm->nodeValue)) {
            $views = preg_replace('/[^0-9]/', '', $elm->nodeValue);
        } else {
            $views = null;
        }
    } else {
        echo "Error!";
    }

    return isset($views) ? $views : null;
}

Answer 1

Here is what I've determined...

1. If you var_dump() on $request you can see that it's giving you a 302 code (redirect) rather than a 200 (ok).
2. Changing CURLOPT_FOLLOWLOCATION to true or commenting it out entirely makes the error go away, but now we're getting a different page from the one expected.

I ran the following to see where I was being redirected to:

$htm = file_get_contents("https://www.facebook.com/TaylorSwift/videos/10153665021155369/");
var_dump($htm);

This gave me a page saying I was using an outdated browser, and needed to update it. So apparently Facebook doesn't like the User Agent.

I updated it as follows:

curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/44.0.2');

That appears to solve the problem.

Answer 2

Personally I prefer to use Simplehtmldom.

FB like other high traffic sites do update their source to help prevent scraping. You may in the future have to adjust your node search.

<?php
$ua = "Mozilla/5.0 (Windows NT 5.0) AppleWebKit/5321 (KHTML, like Gecko) Chrome/13.0.872.0 Safari/5321"; // must be a valid User Agent
ini_set('user_agent', $ua);

require_once('simplehtmldom/simple_html_dom.php'); // http://simplehtmldom.sourceforge.net/

Function Scrape_FB_Views($url) {

    IF (!filter_var($url, FILTER_VALIDATE_URL) === false) {

        // Create DOM from URL
        $html = file_get_html($url);
        IF ($html) {

            IF (($html->find('span[class=fcg]', 3))) { // 4th instance of span with fcg class
                $text = trim($html->find('span[class=fcg]', 3)->plaintext); // get content of span as plain text
                $result = preg_replace('/[^0-9]/', '', $text); // replace all non-numeric characters
            }ELSE{
                $result = "Node is no longer valid."
            }

        }ELSE{
            $result = "Could not get HTML.";
        }
    }ELSE{
        $result = "URL is invalid.";
    }

    return $result;

}

$url = "https://www.facebook.com/TaylorSwift/videos/10153665021155369/";
echo("<p>".Scrape_FB_Views($url)."</p>");
?>