CODEWITHSUNDEEP
phpencodinggzipdecoding
Ian
Ian

Reputation: 12241

Decode gzipped web page retrieved via cURL in PHP

I'm retrieving a gzipped web page via curl, but when I output the retrieved content to the browser I just get the raw gzipped data. How can I decode the data in PHP?

One method I found was to write the content to a tmp file and then ...

$f = gzopen($filename,"r");
$content = gzread($filename,250000);
gzclose($f);

.... but man, there's got to be a better way.

Edit: This isn't a file, but a gzipped html page returned by a web server.

Upvotes: 66

Views: 58553

Answers (2)

Jonas Lejon
Jonas Lejon

Reputation: 3239

The following command enables cURL's "auto encoding" mode, where it will announce to the server which encoding methods it supports (via the Accept-Encoding header), and then automatically decompress the response for you:

// Allow cURL to use gzip compression, or any other supported encoding
// A blank string activates 'auto' mode
curl_setopt($ch, CURLOPT_ENCODING , '');

If you specifically want to force the header to be Accept-Encoding: gzip you can use this command instead:

// Allow cURL to use gzip compression, or any other supported encoding
curl_setopt($ch, CURLOPT_ENCODING , 'gzip');

Read more in the PHP documentation: curl_setopt.

Thanks to commenters for helping improve this answer.

Upvotes: 159

Maryam Jeddian
Maryam Jeddian

Reputation: 51

Versatile GUNZIP function:

   function gunzip($zipped) {
      $offset = 0;
      if (substr($zipped,0,2) == "\x1f\x8b")
         $offset = 2;
      if (substr($zipped,$offset,1) == "\x08")  {
         # file_put_contents("tmp.gz", substr($zipped, $offset - 2));
         return gzinflate(substr($zipped, $offset + 8));
      }
      return "Unknown Format";
   }

Example of integrating function with CURL:

      $headers_enabled = 1;
      curl_setopt($c, CURLOPT_HEADER,  $headers_enabled)
      $ret = curl_exec($c);

      if ($headers_enabled) {
         # file_put_contents("preungzip.html", $ret);

         $sections = explode("\x0d\x0a\x0d\x0a", $ret, 2);
         while (!strncmp($sections[1], 'HTTP/', 5)) {
            $sections = explode("\x0d\x0a\x0d\x0a", $sections[1], 2);
         }
         $headers = $sections[0];
         $data = $sections[1];

         if (preg_match('/^Content-Encoding: gzip/mi', $headers)) {
            printf("gzip header found\n");
            return gunzip($data);
         }
      }

      return $ret;

Upvotes: 5

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