file_get_contents script works with some websites

问题:

I'm looking to build a PHP script that parses HTML for particular tags. I've been using this code block, adapted from this tutorial:

<?php 
$data = file_get_contents('http://www.google.com');
$regex = '/<title>(.+?)</';
preg_match($regex,$data,$match);
var_dump($match); 
echo $match[1];
?>

The script works with some websites (like google, above), but when I try it with other websites (like, say, freshdirect), I get this error:

"Warning: file_get_contents(http://www.freshdirect.com) [function.file-get-contents]: failed to open stream: HTTP request failed!"

I've seen a bunch of great suggestions on StackOverflow, for example to enable extension=php_openssl.dll in php.ini. But (1) my version of php.ini didn't have extension=php_openssl.dll in it, and (2) when I added it to the extensions section and restarted the WAMP server, per this thread, still no success.

Would someone mind pointing me in the right direction? Thank you very much!

回答1:

$html = file_get_html('http://google.com/');
$title = $html->find('title')->innertext;

Or if you prefer with preg_match and you should be really using cURL instead of fgc...

function curl($url){

    $headers[]  = "User-Agent:Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13";
    $headers[]  = "Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    $headers[]  = "Accept-Language:en-us,en;q=0.5";
    $headers[]  = "Accept-Encoding:gzip,deflate";
    $headers[]  = "Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.7";
    $headers[]  = "Keep-Alive:115";
    $headers[]  = "Connection:keep-alive";
    $headers[]  = "Cache-Control:max-age=0";

    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($curl, CURLOPT_ENCODING, "gzip");
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
    $data = curl_exec($curl);
    curl_close($curl);
    return $data;

}


$data = curl('http://www.google.com');
$regex = '#<title>(.*?)</title>#mis';
preg_match($regex,$data,$match);
var_dump($match); 
echo $match[1];

回答2:

It just requires a user-agent ("any" really, any string suffices):

file_get_contents("http://www.freshdirect.com",false,stream_context_create(
    array("http" => array("user_agent" => "any"))
));

See more options.

Of course, you can set user_agent in your ini:

 ini_set("user_agent","any");
 echo file_get_contents("http://www.freshdirect.com");

... but I prefer to be explicit for the next programmer working on it.

回答3:

Another option: Some hosts disable CURLOPT_FOLLOWLOCATION so recursive is what you want, also will log into a text file any errors. Also a simple example of how to use DOMDocument() to extract the content, obviously its not extensive but something you could build appon.

<?php 
function file_get_site($url){
(function_exists('curl_init')) ? '' : die('cURL Must be installed. Ask your host to enable it or uncomment extension=php_curl.dll in php.ini');
$curl = curl_init();
$header[0] = "Accept: text/xml,application/xml,application/xhtml+xml,";
$header[0] .= "text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5";
$header[] = "Cache-Control: max-age=0";
$header[] = "Connection: keep-alive";
$header[] = "Keep-Alive: 300";
$header[] = "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7";
$header[] = "Accept-Language: en-us,en;q=0.5";
$header[] = "Pragma: ";

curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0 Firefox/5.0');
curl_setopt($curl, CURLOPT_HTTPHEADER, $header);
curl_setopt($curl, CURLOPT_HEADER, true);
curl_setopt($curl, CURLOPT_REFERER, $url);
curl_setopt($curl, CURLOPT_ENCODING, 'gzip,deflate');
curl_setopt($curl, CURLOPT_AUTOREFERER, true);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_TIMEOUT, 60);

$html = curl_exec($curl);

$status = curl_getinfo($curl);
curl_close($curl);

if($status['http_code']!=200){
    if($status['http_code'] == 301 || $status['http_code'] == 302) {
        list($header) = explode("\r\n\r\n", $html, 2);
        $matches = array();
        preg_match("/(Location:|URI:)[^(\n)]*/", $header, $matches);
        $url = trim(str_replace($matches[1],"",$matches[0]));
        $url_parsed = parse_url($url);
        return (isset($url_parsed))? file_get_site($url):'';
    }
    $oline='';
    foreach($status as $key=>$eline){$oline.='['.$key.']'.$eline.' ';}
    $line =$oline." \r\n ".$url."\r\n-----------------\r\n";
    $handle = @fopen('./curl.error.log', 'a');
    fwrite($handle, $line);
    return FALSE;
}
return $html;
}


function get_content_tags($source,$tag,$id=null,$value=null){
    $xml = new DOMDocument();
    @$xml->loadHTML($source);

    foreach($xml->getElementsByTagName($tag) as $tags) {
        if($id!=null){
            if($tags->getAttribute($id)==$value){
                return $tags->getAttribute('content');
            }
        }
        return $tags->nodeValue;
    }
}


$source = file_get_site('http://www.freshdirect.com/about/index.jsp');

echo get_content_tags($source,'title'); //FreshDirect

echo get_content_tags($source,'meta','name','description'); //Online grocer providing high quality fresh......

?>