(PECL pecl_http >= 0.1.0)
http_match_etag — Match ETag
$etag
   [, bool $for_range = false
  ] )Matches the given ETag against the clients If-Match resp. If-None-Match HTTP headers.
etagthe ETag to match
for_range
       if set to TRUE, the header usually used to validate HTTP ranges will be checked
      
   Returns TRUE if ETag matches or the header contained the asterisk ("*"), else FALSE.