/** * Content-type sniffing * * Based on the rules in http://tools.ietf.org/html/draft-abarth-mime-sniff-06 * * This is used since we can't always trust Content-Type headers, and is based * upon the HTML5 parsing rules. * * * This class can be overloaded with {@see SimplePie::set_content_type_sniffer_class()} * * @package SimplePie * @subpackage HTTP */ class SimplePie_Content_Type_Sniffer { /** * File object * * @var SimplePie_File */ var $file; /** * Create an instance of the class with the input file * * @param SimplePie_Content_Type_Sniffer $file Input file */ public function __construct($file) { $this->file = $file; } /** * Get the Content-Type of the specified file * * @return string Actual Content-Type */ public function get_type() { if (isset($this->file->headers['content-type'])) { if (!isset($this->file->headers['content-encoding']) && ($this->file->headers['content-type'] === 'text/plain' || $this->file->headers['content-type'] === 'text/plain; charset=ISO-8859-1' || $this->file->headers['content-type'] === 'text/plain; charset=iso-8859-1' || $this->file->headers['content-type'] === 'text/plain; charset=UTF-8')) { return $this->text_or_binary(); } if (($pos = strpos($this->file->headers['content-type'], ';')) !== false) { $official = substr($this->file->headers['content-type'], 0, $pos); } else { $official = $this->file->headers['content-type']; } $official = trim(strtolower($official)); if ($official === 'unknown/unknown' || $official === 'application/unknown') { return $this->unknown(); } elseif (substr($official, -4) === '+xml' || $official === 'text/xml' || $official === 'application/xml') { return $official; } elseif (substr($official, 0, 6) === 'image/') { if ($return = $this->image()) { return $return; } else { return $official; } } elseif ($official === 'text/html') { return $this->feed_or_html(); } else { return $official; } } else { return $this->unknown(); } } /** * Sniff text or binary * * @return string Actual Content-Type */ public function text_or_binary() { if (substr($this->file->body, 0, 2) === "\xFE\xFF" || substr($this->file->body, 0, 2) === "\xFF\xFE" || substr($this->file->body, 0, 4) === "\x00\x00\xFE\xFF" || substr($this->file->body, 0, 3) === "\xEF\xBB\xBF") { return 'text/plain'; } elseif (preg_match('/[\x00-\x08\x0E-\x1A\x1C-\x1F]/', $this->file->body)) { return 'application/octect-stream'; } else { return 'text/plain'; } } /** * Sniff unknown * * @return string Actual Content-Type */ public function unknown() { $ws = strspn($this->file->body, "\x09\x0A\x0B\x0C\x0D\x20"); if (strtolower(substr($this->file->body, $ws, 14)) === 'file->body, $ws, 5)) === 'file->body, $ws, 7)) === 'file->body, 0, 5) === '%PDF-') { return 'application/pdf'; } elseif (substr($this->file->body, 0, 11) === '%!PS-Adobe-') { return 'application/postscript'; } elseif (substr($this->file->body, 0, 6) === 'GIF87a' || substr($this->file->body, 0, 6) === 'GIF89a') { return 'image/gif'; } elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A") { return 'image/png'; } elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF") { return 'image/jpeg'; } elseif (substr($this->file->body, 0, 2) === "\x42\x4D") { return 'image/bmp'; } elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00") { return 'image/vnd.microsoft.icon'; } else { return $this->text_or_binary(); } } /** * Sniff images * * @return string Actual Content-Type */ public function image() { if (substr($this->file->body, 0, 6) === 'GIF87a' || substr($this->file->body, 0, 6) === 'GIF89a') { return 'image/gif'; } elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A") { return 'image/png'; } elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF") { return 'image/jpeg'; } elseif (substr($this->file->body, 0, 2) === "\x42\x4D") { return 'image/bmp'; } elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00") { return 'image/vnd.microsoft.icon'; } else { return false; } } /** * Sniff HTML * * @return string Actual Content-Type */ public function feed_or_html() { $len = strlen($this->file->body); $pos = strspn($this->file->body, "\x09\x0A\x0D\x20"); while ($pos < $len) { switch ($this->file->body[$pos]) { case "\x09": case "\x0A": case "\x0D": case "\x20": $pos += strspn($this->file->body, "\x09\x0A\x0D\x20", $pos); continue 2; case '<': $pos++; break; default: return 'text/html'; } if (substr($this->file->body, $pos, 3) === '!--') { $pos += 3; if ($pos < $len && ($pos = strpos($this->file->body, '-->', $pos)) !== false) { $pos += 3; } else { return 'text/html'; } } elseif (substr($this->file->body, $pos, 1) === '!') { if ($pos < $len && ($pos = strpos($this->file->body, '>', $pos)) !== false) { $pos++; } else { return 'text/html'; } } elseif (substr($this->file->body, $pos, 1) === '?') { if ($pos < $len && ($pos = strpos($this->file->body, '?>', $pos)) !== false) { $pos += 2; } else { return 'text/html'; } } elseif (substr($this->file->body, $pos, 3) === 'rss' || substr($this->file->body, $pos, 7) === 'rdf:RDF') { return 'application/rss+xml'; } elseif (substr($this->file->body, $pos, 4) === 'feed') { return 'application/atom+xml'; } else { return 'text/html'; } } return 'text/html'; } }