get_meta_tags

(PHP 3 >= 3.0.4, PHP 4, PHP 5)

get_meta_tags --  Extracts all meta tag content attributes from a file and returns an array

Description

array get_meta_tags ( string filename [, bool use_include_path] )

Opens filename and parses it line by line for <meta> tags in the file. This can be a local file or an URL. The parsing stops at </head>.

Setting use_include_path to TRUE will result in PHP trying to open the file along the standard include path as per the include_path directive. This is used for local files, not URLs.

Пример 1. What get_meta_tags() parses

<meta name="author" content="name">
<meta name="keywords" content="php documentation">
<meta name="DESCRIPTION" content="a php manual">
<meta name="geo.position" content="49.33;-86.59">
</head> <!-- parsing stops here -->
(pay attention to line endings - PHP uses a native function to parse the input, so a Mac file won't work on Unix).

The value of the name property becomes the key, the value of the content property becomes the value of the returned array, so you can easily use standard array functions to traverse it or access single values. Special characters in the value of the name property are substituted with '_', the rest is converted to lower case. If two meta tags have the same name, only the last one is returned.

Пример 2. What get_meta_tags() returns

<?php
// Assuming the above tags are at www.example.com
$tags = get_meta_tags('http://www.example.com/');

// Notice how the keys are all lowercase now, and
// how . was replaced by _ in the key.
echo $tags['author'];      // name
echo $tags['keywords'];    // php documentation
echo $tags['description'];  // a php manual
echo $tags['geo_position']; // 49.33;-86.59
?>

Замечание: As of PHP 4.0.5, get_meta_tags() supports unquoted HTML attributes.

See also htmlentities() and urlencode().



get_meta_tags
jimmyxx at gmail dot com
20-Sep-2005 12:37
I used this as part of my mini php search based search engine - it really slowed the whole thing down. I wrote this function to read HTML (just fetch the file or use something like snoopy) and extract the meta data via a simple regex, works a treat and made my crawler much faster:

<?php

function get_meta_data($html) {

   preg_match_all(
   "|<meta[^>]+name=\\"([^"]*)\\"[^>]+content="([^\\"]*)"[^>]+>|i",  $html, $out,PREG_PATTERN_ORDER);

   for ($i=0;$i < count($out[1]);$i++) {
       // loop through the meta data - add your own tags here if you need
       if (strtolower($out[1][$i]) == "keywords") $meta['keywords'] = $out[2][$i];
       if (strtolower($out[1][$i]) == "description") $meta['description'] = $out[2][$i];
   }

return $meta;   
}

?>
mariano at cricava dot com
12-Sep-2005 05:18
Based on Michael Knapp's code, and adding some regex, here's a function that will get all meta tags and the title based on a URL. If there's an error, it will return false. Using the function getUrlContents(), also included, it takes care of META REFRESH re-directions, following up to the specified number of redirections. Please note that the regular expressions included were split into strings because php.net was complaining about the line being to long ;)

<?php
function getUrlData($url)
{
   $result = false;
  
   $contents = getUrlContents($url);

   if (isset($contents) && is_string($contents))
   {
       $title = null;
       $metaTags = null;
      
       preg_match('/<title>([^>]*)<\/title>/si', $contents, $match );

       if (isset($match) && is_array($match) && count($match) > 0)
       {
           $title = strip_tags($match[1]);
       }
      
       preg_match_all('/<[\s]*meta[\s]*name="?' . '([^>"]*)"?[\s]*' . 'content="?([^>"]*)"?[\s]*[\/]?[\s]*>/si', $contents, $match);
      
       if (isset($match) && is_array($match) && count($match) == 3)
       {
           $originals = $match[0];
           $names = $match[1];
           $values = $match[2];
          
           if (count($originals) == count($names) && count($names) == count($values))
           {
               $metaTags = array();
              
               for ($i=0, $limiti=count($names); $i < $limiti; $i++)
               {
                   $metaTags[$names[$i]] = array (
                       'html' => htmlentities($originals[$i]),
                       'value' => $values[$i]
                   );
               }
           }
       }
      
       $result = array (
           'title' => $title,
           'metaTags' => $metaTags
       );
   }
  
   return $result;
}

function getUrlContents($url, $maximumRedirections = null, $currentRedirection = 0)
{
   $result = false;
  
   $contents = @file_get_contents($url);
  
   // Check if we need to go somewhere else
  
   if (isset($contents) && is_string($contents))
   {
       preg_match_all('/<[\s]*meta[\s]*http-equiv="?REFRESH"?' . '[\s]*content="?[0-9]*;[\s]*URL[\s]*=[\s]*([^>"]*)"?' . '[\s]*[\/]?[\s]*>/si', $contents, $match);
      
       if (isset($match) && is_array($match) && count($match) == 2 && count($match[1]) == 1)
       {
           if (!isset($maximumRedirections) || $currentRedirection < $maximumRedirections)
           {
               return getUrlContents($match[1][0], $maximumRedirections, ++$currentRedirection);
           }
          
           $result = false;
       }
       else
       {
           $result = $contents;
       }
   }
  
   return $contents;
}
?>

Here's an example of its usage. Check that the included URL has a META REFRESH redirection:

<?php
$result = getUrlData('http://www.marianoiglesias.com.ar/');

echo '<pre>'; print_r($result); echo '</pre>';

?>

For the above code the output would be:

<?php
Array
(
   [title] => Mariano Iglesias: El Eternauta   
   [metaTags] => Array
       (
           [description] => Array
               (
                   [html] => <meta name="description" content="Java, PHP, and some other technological mumble jumble. Also, some real-life stuff as well." />
                   [value] => Java, PHP, and some other technological mumble jumble. Also, some real-life stuff as well.
               )

           [DC.title] => Array
               (
                   [html] => <meta name="DC.title" content="Mariano Iglesias - Weblog" />
                   [value] => Mariano Iglesias - Weblog
               )

           [ICBM] => Array
               (
                   [html] => <meta name="ICBM" content="-34.6017, -58.3956" />
                   [value] => -34.6017, -58.3956
               )

           [geo.position] => Array
               (
                   [html] => <meta name="geo.position" content="-34.6017;-58.3956" />
                   [value] => -34.6017;-58.3956
               )

           [geo.region] => Array
               (
                   [html] => <meta name="geo.region" content="AR-BA">
                   [value] => AR-BA
               )

           [geo.placename] => Array
               (
                   [html] => <meta name="geo.placename" content="Buenos Aires">
                   [value] => Buenos Aires
               )

       )

)
?>
Michael Knapp
12-Mar-2005 12:47
Tim's code is good (thanks Tim), except it won't work very well if the tag is part of a long non-breaking string.

E.g. try getting the title from Google Maps (http://www.google.com/maps).

A better solution is:

<?php
$title = "";
  
if ($fp = @fopen( $_POST['url'], 'r' )) {

   $cont = "";
  
   // read the contents
   while( !feof( $fp ) ) {
       $buf = trim(fgets( $fp, 4096 )) ;
       $cont .= $buf;
   }

   // get tag contents
   @preg_match( "/<title>([a-z 0-9]*)<\/title>/si", $cont, $match );
  
   // tag contents
   $title = strip_tags(@$match[ 1 ]);
}

?>

Note the strip_tags. Another thing to be careful of is to check for ", <, and >. You will need to strip those out if you are posting the output to a form.

Also, it is probably best to use the /i modifier, because some people might code <TITLE> etc...
rehfeld
05-Feb-2005 06:45
in response to
jp at webgraphe dot com

this function grabs meta tags, not http headers

if you need the headers

<?php

$fp = fopen('http://example.org/somepage.html', 'r');

// the variable $http_response_header magically appears
print_r($http_response_header);

// or
$meta_data = stream_get_meta_data($fp);
print_r($meta_data);

?>
tim dot bennett at haveaniceplay dot com
01-Feb-2005 07:43
If you want to get the contents of tags other than meta you can use:

<?php

$page = "http://www.mysite.com/apage.php";

   // tags
   $start = '<atag>';
   $end = '<\/atag>';

   // open the file
   $fp = fopen( $page, 'r' );

   $cont = "";

   // read the contents
   while( !feof( $fp ) ) {
       $buf = trim( fgets( $fp, 4096 ) );
       $cont .= $buf;
   }
  
   // get tag contents
   preg_match( "/$start(.*)$end/s", $cont, $match );

   // tag contents
   $contents = $match[ 1 ];

?>
jp at webgraphe dot com
12-Dec-2003 05:37
If the URL is doing a redirection using the headers (like you would do with PHP function header("Location: URL");), the page has no content (in general). It appears get_meta_tags() doesn't catch that kind of redirection (like cURL would do) and it lead me to a timeout of my script.

I experienced this in a spider I wrote in order to feed my database of all available pages on my site and one link was linking to a page that simply has the following code:

<?php
  header("Location: sections.php?section=home");
  exit();
?>

That made my script hang for a moment and apparently, get_meta_tags() wasn't even able to return me an error.

JP.
bill.neumann at hatworld.com
13-Mar-2003 07:50
The get_meta_tags function does not seem to be able to grab values if there are spaces between the attribute, the equal sign, and the opening quote marks.
20-Dec-2001 11:01
Tested PHP 4.0.6<br>
get_meta_tags() seems to look only in the beginning of a file, meaning that e.g. if there is a lot of PHP code before the HTML header it will return nothing ...<br>
Tested using get_meta_tags() on local files with about 9000 characters of PHP code before HTML HEADER.<br>
Workaround: if possible move code after header or if not: include a file.
Ben dot Davis at furman dot edu
30-Jul-2001 03:29
I have found that for large searches, get_meta_tags is very slow.  I created a large search engine for a website that couldnt use a database and I first tried pulling out the meta tags. 
I have found that it is actually much faster to use eregi to pull out the meta tags.  This code below pulls out the description:

if (eregi ("<meta name=\"description\" content=[^>]*", $contents, $descresult))
                               {
                                   $description = explode("<meta name=\"description\" content=", $descresult[0]);
                                   echo "<font face=\"Arial\" size=2>$description[1]</font>";
                                  
                               }
richard at pifmagazine dot com
21-Apr-2000 05:17
Something that is not mentioned above and should be : When using get_meta_tags on a remote PHP page the page will be parsed before the meta tags are returned - so you can capture meta tags generated dynamically (by PHP??) on the remote end.
<p>
This DOES NOT work the same way when getting meta tags on local file systems.  Local files are not parsed through the web server before returning to get_meta_tags().  If the META tag is hard-coded into the page, you'll be fine - but if it dynamically generated you will not be able to capture it unless you use the full URL when calling your local files.
richard at pifmagazine dot com
21-Apr-2000 05:00
An Important Note about META tags and this function :  if your META tag contains newline "\n"  characters, get_meta_tags() will return a NULL value for that name property.  Removing the newlines from the source META tag corrects the problem.

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 Last updated: Tue, 15 Nov 2005