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   1  <?php
   2  
   3  /**
   4  * Project:     MagpieRSS: a simple RSS integration tool
   5  * File:        rss_parse.inc  - parse an RSS or Atom feed
   6  *               return as a simple object.
   7  *
   8  * Handles RSS 0.9x, RSS 2.0, RSS 1.0, and Atom 0.3
   9  *
  10  * The lastest version of MagpieRSS can be obtained from:
  11  * http://magpierss.sourceforge.net
  12  *
  13  * For questions, help, comments, discussion, etc., please join the
  14  * Magpie mailing list:
  15  * magpierss-general@lists.sourceforge.net
  16  *
  17  * @author           Kellan Elliott-McCrea <kellan@protest.net>
  18  * @version          0.7a
  19  * @license          GPL
  20  *
  21  */
  22  
  23  define('RSS', 'RSS');
  24  define('ATOM', 'Atom');
  25  
  26  require_once  (MAGPIE_DIR . 'rss_utils.inc');
  27  
  28  /**
  29  * Hybrid parser, and object, takes RSS as a string and returns a simple object.
  30  *
  31  * see: rss_fetch.inc for a simpler interface with integrated caching support
  32  *
  33  */
  34  class MagpieRSS {
  35      var $parser;
  36      
  37      var $current_item   = array();  // item currently being parsed
  38      var $items          = array();  // collection of parsed items
  39      var $channel        = array();  // hash of channel fields
  40      var $textinput      = array();
  41      var $image          = array();
  42      var $feed_type;
  43      var $feed_version;
  44      var $encoding       = '';       // output encoding of parsed rss
  45      
  46      var $_source_encoding = '';     // only set if we have to parse xml prolog
  47      
  48      var $ERROR = "";
  49      var $WARNING = "";
  50      
  51      // define some constants
  52      
  53      var $_CONTENT_CONSTRUCTS = array('content', 'summary', 'info', 'title', 'tagline', 'copyright');
  54      var $_KNOWN_ENCODINGS    = array('UTF-8', 'US-ASCII', 'ISO-8859-1');
  55  
  56      // parser variables, useless if you're not a parser, treat as private
  57      var $stack              = array(); // parser stack
  58      var $inchannel          = false;
  59      var $initem             = false;
  60      var $incontent          = false; // if in Atom <content mode="xml"> field 
  61      var $intextinput        = false;
  62      var $inimage            = false;
  63      var $current_field      = '';
  64      var $current_namespace  = false;
  65      
  66  
  67      /**
  68       *  Set up XML parser, parse source, and return populated RSS object..
  69       *   
  70       *  @param string $source           string containing the RSS to be parsed
  71       *
  72       *  NOTE:  Probably a good idea to leave the encoding options alone unless
  73       *         you know what you're doing as PHP's character set support is
  74       *         a little weird.
  75       *
  76       *  NOTE:  A lot of this is unnecessary but harmless with PHP5 
  77       *
  78       *
  79       *  @param string $output_encoding  output the parsed RSS in this character 
  80       *                                  set defaults to ISO-8859-1 as this is PHP's
  81       *                                  default.
  82       *
  83       *                                  NOTE: might be changed to UTF-8 in future
  84       *                                  versions.
  85       *                               
  86       *  @param string $input_encoding   the character set of the incoming RSS source. 
  87       *                                  Leave blank and Magpie will try to figure it
  88       *                                  out.
  89       *                                  
  90       *                                   
  91       *  @param bool   $detect_encoding  if false Magpie won't attempt to detect
  92       *                                  source encoding. (caveat emptor)
  93       *
  94       */
  95      function MagpieRSS ($source, $output_encoding='ISO-8859-1', 
  96                          $input_encoding=null, $detect_encoding=true) 
  97      {   
  98          # if PHP xml isn't compiled in, die
  99          #
 100          if (!function_exists('xml_parser_create')) {
 101              $this->error( "Failed to load PHP's XML Extension. " . 
 102                            "http://www.php.net/manual/en/ref.xml.php",
 103                             E_USER_ERROR );
 104          }
 105          
 106          list($parser, $source) = $this->create_parser($source, 
 107                  $output_encoding, $input_encoding, $detect_encoding);
 108          
 109          
 110          if (!is_resource($parser)) {
 111              $this->error( "Failed to create an instance of PHP's XML parser. " .
 112                            "http://www.php.net/manual/en/ref.xml.php",
 113                            E_USER_ERROR );
 114          }
 115  
 116          
 117          $this->parser = $parser;
 118          
 119          # pass in parser, and a reference to this object
 120          # setup handlers
 121          #
 122          xml_set_object( $this->parser, $this );
 123          xml_set_element_handler($this->parser, 
 124                  'feed_start_element', 'feed_end_element' );
 125                          
 126          xml_set_character_data_handler( $this->parser, 'feed_cdata' ); 
 127      
 128          $status = xml_parse( $this->parser, $source );
 129          
 130          if (! $status ) {
 131              $errorcode = xml_get_error_code( $this->parser );
 132              if ( $errorcode != XML_ERROR_NONE ) {
 133                  $xml_error = xml_error_string( $errorcode );
 134                  $error_line = xml_get_current_line_number($this->parser);
 135                  $error_col = xml_get_current_column_number($this->parser);
 136                  $errormsg = "$xml_error at line $error_line, column $error_col";
 137  
 138                  $this->error( $errormsg );
 139              }
 140          }
 141          
 142          xml_parser_free( $this->parser );
 143  
 144          $this->normalize();
 145      }
 146      
 147      function feed_start_element($p, $element, &$attrs) {
 148          $el = $element = strtolower($element);
 149          $attrs = array_change_key_case($attrs, CASE_LOWER);
 150          
 151          // check for a namespace, and split if found
 152          $ns = false;
 153          if ( strpos( $element, ':' ) ) {
 154              list($ns, $el) = split( ':', $element, 2); 
 155          }
 156          if ( $ns and $ns != 'rdf' ) {
 157              $this->current_namespace = $ns;
 158          }
 159              
 160          # if feed type isn't set, then this is first element of feed
 161          # identify feed from root element
 162          #
 163          if (!isset($this->feed_type) ) {
 164              if ( $el == 'rdf' ) {
 165                  $this->feed_type = RSS;
 166                  $this->feed_version = '1.0';
 167              }
 168              elseif ( $el == 'rss' ) {
 169                  $this->feed_type = RSS;
 170                  $this->feed_version = $attrs['version'];
 171              }
 172              elseif ( $el == 'feed' ) {
 173                  $this->feed_type = ATOM;
 174                  $this->feed_version = $attrs['version'];
 175                  $this->inchannel = true;
 176              }
 177              return;
 178          }
 179      
 180          if ( $el == 'channel' ) 
 181          {
 182              $this->inchannel = true;
 183          }
 184          elseif ($el == 'item' or $el == 'entry' ) 
 185          {
 186              $this->initem = true;
 187              if ( isset($attrs['rdf:about']) ) {
 188                  $this->current_item['about'] = $attrs['rdf:about']; 
 189              }
 190          }
 191          
 192          // if we're in the default namespace of an RSS feed,
 193          //  record textinput or image fields
 194          elseif ( 
 195              $this->feed_type == RSS and 
 196              $this->current_namespace == '' and 
 197              $el == 'textinput' ) 
 198          {
 199              $this->intextinput = true;
 200          }
 201          
 202          elseif (
 203              $this->feed_type == RSS and 
 204              $this->current_namespace == '' and 
 205              $el == 'image' ) 
 206          {
 207              $this->inimage = true;
 208          }
 209          
 210          # handle atom content constructs
 211          elseif ( $this->feed_type == ATOM and in_array($el, $this->_CONTENT_CONSTRUCTS) )
 212          {
 213              // avoid clashing w/ RSS mod_content
 214              if ($el == 'content' ) {
 215                  $el = 'atom_content';
 216              }
 217              
 218              $this->incontent = $el;
 219              
 220              
 221          }
 222          
 223          // if inside an Atom content construct (e.g. content or summary) field treat tags as text
 224          elseif ($this->feed_type == ATOM and $this->incontent ) 
 225          {
 226              // if tags are inlined, then flatten
 227              $attrs_str = join(' ', 
 228                      array_map('map_attrs', 
 229                      array_keys($attrs), 
 230                      array_values($attrs) ) );
 231              
 232              $this->append_content( "<$element $attrs_str>"  );
 233                      
 234              array_unshift( $this->stack, $el );
 235          }
 236          
 237          // Atom support many links per containging element.
 238          // Magpie treats link elements of type rel='alternate'
 239          // as being equivalent to RSS's simple link element.
 240          //
 241          elseif ($this->feed_type == ATOM and $el == 'link' ) 
 242          {
 243              if ( isset($attrs['rel']) and $attrs['rel'] == 'alternate' ) 
 244              {
 245                  $link_el = 'link';
 246              }
 247              else {
 248                  $link_el = 'link_' . $attrs['rel'];
 249              }
 250              
 251              $this->append($link_el, $attrs['href']);
 252          }
 253          // set stack[0] to current element
 254          else {
 255              array_unshift($this->stack, $el);
 256          }
 257      }
 258      
 259  
 260      
 261      function feed_cdata ($p, $text) {
 262          
 263          if ($this->feed_type == ATOM and $this->incontent) 
 264          {
 265              $this->append_content( $text );
 266          }
 267          else {
 268              $current_el = join('_', array_reverse($this->stack));
 269              $this->append($current_el, $text);
 270          }
 271      }
 272      
 273      function feed_end_element ($p, $el) {
 274          $el = strtolower($el);
 275          
 276          if ( $el == 'item' or $el == 'entry' ) 
 277          {
 278              $this->items[] = $this->current_item;
 279              $this->current_item = array();
 280              $this->initem = false;
 281          }
 282          elseif ($this->feed_type == RSS and $this->current_namespace == '' and $el == 'textinput' ) 
 283          {
 284              $this->intextinput = false;
 285          }
 286          elseif ($this->feed_type == RSS and $this->current_namespace == '' and $el == 'image' ) 
 287          {
 288              $this->inimage = false;
 289          }
 290          elseif ($this->feed_type == ATOM and in_array($el, $this->_CONTENT_CONSTRUCTS) )
 291          {   
 292              $this->incontent = false;
 293          }
 294          elseif ($el == 'channel' or $el == 'feed' ) 
 295          {
 296              $this->inchannel = false;
 297          }
 298          elseif ($this->feed_type == ATOM and $this->incontent  ) {
 299              // balance tags properly
 300              // note:  i don't think this is actually neccessary
 301              if ( $this->stack[0] == $el ) 
 302              {
 303                  $this->append_content("</$el>");
 304              }
 305              else {
 306                  $this->append_content("<$el />");
 307              }
 308  
 309              array_shift( $this->stack );
 310          }
 311          else {
 312              array_shift( $this->stack );
 313          }
 314          
 315          $this->current_namespace = false;
 316      }
 317      
 318      function concat (&$str1, $str2="") {
 319          if (!isset($str1) ) {
 320              $str1="";
 321          }
 322          $str1 .= $str2;
 323      }
 324      
 325      
 326      
 327      function append_content($text) {
 328          if ( $this->initem ) {
 329              $this->concat( $this->current_item[ $this->incontent ], $text );
 330          }
 331          elseif ( $this->inchannel ) {
 332              $this->concat( $this->channel[ $this->incontent ], $text );
 333          }
 334      }
 335      
 336      // smart append - field and namespace aware
 337      function append($el, $text) {
 338          if (!$el) {
 339              return;
 340          }
 341          if ( $this->current_namespace ) 
 342          {
 343              if ( $this->initem ) {
 344                  $this->concat(
 345                      $this->current_item[ $this->current_namespace ][ $el ], $text);
 346              }
 347              elseif ($this->inchannel) {
 348                  $this->concat(
 349                      $this->channel[ $this->current_namespace][ $el ], $text );
 350              }
 351              elseif ($this->intextinput) {
 352                  $this->concat(
 353                      $this->textinput[ $this->current_namespace][ $el ], $text );
 354              }
 355              elseif ($this->inimage) {
 356                  $this->concat(
 357                      $this->image[ $this->current_namespace ][ $el ], $text );
 358              }
 359          }
 360          else {
 361              if ( $this->initem ) {
 362                  $this->concat(
 363                      $this->current_item[ $el ], $text);
 364              }
 365              elseif ($this->intextinput) {
 366                  $this->concat(
 367                      $this->textinput[ $el ], $text );
 368              }
 369              elseif ($this->inimage) {
 370                  $this->concat(
 371                      $this->image[ $el ], $text );
 372              }
 373              elseif ($this->inchannel) {
 374                  $this->concat(
 375                      $this->channel[ $el ], $text );
 376              }
 377              
 378          }
 379      }
 380      
 381      function normalize () {
 382          // if atom populate rss fields
 383          if ( $this->is_atom() ) {
 384              $this->channel['description'] = $this->channel['tagline'];
 385              for ( $i = 0; $i < count($this->items); $i++) {
 386                  $item = $this->items[$i];
 387                  if ( isset($item['summary']) )
 388                      $item['description'] = $item['summary'];
 389                  if ( isset($item['atom_content']))
 390                      $item['content']['encoded'] = $item['atom_content'];
 391                  
 392                  $atom_date = (isset($item['issued']) ) ? $item['issued'] : $item['modified'];
 393                  if ( $atom_date ) {
 394                      $epoch = @parse_w3cdtf($item['modified']);
 395                      if ($epoch and $epoch > 0) {
 396                          $item['date_timestamp'] = $epoch;
 397                      }
 398                  }
 399                  
 400                  $this->items[$i] = $item;
 401              }       
 402          }
 403          elseif ( $this->is_rss() ) {
 404              $this->channel['tagline'] = $this->channel['description'];
 405              for ( $i = 0; $i < count($this->items); $i++) {
 406                  $item = $this->items[$i];
 407                  if ( isset($item['description']))
 408                      $item['summary'] = $item['description'];
 409                  if ( isset($item['content']['encoded'] ) )
 410                      $item['atom_content'] = $item['content']['encoded'];
 411                  
 412                  if ( $this->is_rss() == '1.0' and isset($item['dc']['date']) ) {
 413                      $epoch = @parse_w3cdtf($item['dc']['date']);
 414                      if ($epoch and $epoch > 0) {
 415                          $item['date_timestamp'] = $epoch;
 416                      }
 417                  }
 418                  elseif ( isset($item['pubdate']) ) {
 419                      $epoch = @strtotime($item['pubdate']);
 420                      if ($epoch > 0) {
 421                          $item['date_timestamp'] = $epoch;
 422                      }
 423                  }
 424                  
 425                  $this->items[$i] = $item;
 426              }
 427          }
 428      }
 429      
 430      
 431      function is_rss () {
 432          if ( $this->feed_type == RSS ) {
 433              return $this->feed_version; 
 434          }
 435          else {
 436              return false;
 437          }
 438      }
 439      
 440      function is_atom() {
 441          if ( $this->feed_type == ATOM ) {
 442              return $this->feed_version;
 443          }
 444          else {
 445              return false;
 446          }
 447      }
 448  
 449      /**
 450      * return XML parser, and possibly re-encoded source
 451      *
 452      */
 453      function create_parser($source, $out_enc, $in_enc, $detect) {
 454          if ( substr(phpversion(),0,1) == 5) {
 455              $parser = $this->php5_create_parser($in_enc, $detect);
 456          }
 457          else {
 458              list($parser, $source) = $this->php4_create_parser($source, $in_enc, $detect);
 459          }
 460          if ($out_enc) {
 461              $this->encoding = $out_enc;
 462              xml_parser_set_option($parser, XML_OPTION_TARGET_ENCODING, $out_enc);
 463          }
 464          
 465          return array($parser, $source);
 466      }
 467      
 468      /**
 469      * Instantiate an XML parser under PHP5
 470      *
 471      * PHP5 will do a fine job of detecting input encoding
 472      * if passed an empty string as the encoding. 
 473      *
 474      * All hail libxml2!
 475      *
 476      */
 477      function php5_create_parser($in_enc, $detect) {
 478          // by default php5 does a fine job of detecting input encodings
 479          if(!$detect && $in_enc) {
 480              return xml_parser_create($in_enc);
 481          }
 482          else {
 483              return xml_parser_create('');
 484          }
 485      }
 486      
 487      /**
 488      * Instaniate an XML parser under PHP4
 489      *
 490      * Unfortunately PHP4's support for character encodings
 491      * and especially XML and character encodings sucks.  As
 492      * long as the documents you parse only contain characters
 493      * from the ISO-8859-1 character set (a superset of ASCII,
 494      * and a subset of UTF-8) you're fine.  However once you
 495      * step out of that comfy little world things get mad, bad,
 496      * and dangerous to know.
 497      *
 498      * The following code is based on SJM's work with FoF
 499      * @see http://minutillo.com/steve/weblog/2004/6/17/php-xml-and-character-encodings-a-tale-of-sadness-rage-and-data-loss
 500      *
 501      */
 502      function php4_create_parser($source, $in_enc, $detect) {
 503          if ( !$detect ) {
 504              return array(xml_parser_create($in_enc), $source);
 505          }
 506          
 507          if (!$in_enc) {
 508              if (preg_match('/<?xml.*encoding=[\'"](.*?)[\'"].*?>/m', $source, $m)) {
 509                  $in_enc = strtoupper($m[1]);
 510                  $this->source_encoding = $in_enc;
 511              }
 512              else {
 513                  $in_enc = 'UTF-8';
 514              }
 515          }
 516          
 517          if ($this->known_encoding($in_enc)) {
 518              return array(xml_parser_create($in_enc), $source);
 519          }
 520          
 521          // the dectected encoding is not one of the simple encodings PHP knows
 522          
 523          // attempt to use the iconv extension to
 524          // cast the XML to a known encoding
 525          // @see http://php.net/iconv
 526         
 527          if (function_exists('iconv'))  {
 528              $encoded_source = iconv($in_enc,'UTF-8', $source);
 529              if ($encoded_source) {
 530                  return array(xml_parser_create('UTF-8'), $encoded_source);
 531              }
 532          }
 533          
 534          // iconv didn't work, try mb_convert_encoding
 535          // @see http://php.net/mbstring
 536          if(function_exists('mb_convert_encoding')) {
 537              $encoded_source = mb_convert_encoding($source, 'UTF-8', $in_enc );
 538              if ($encoded_source) {
 539                  return array(xml_parser_create('UTF-8'), $encoded_source);
 540              }
 541          }
 542          
 543          // else 
 544          $this->error("Feed is in an unsupported character encoding. ($in_enc) " .
 545                       "You may see strange artifacts, and mangled characters.",
 546                       E_USER_NOTICE);
 547              
 548          return array(xml_parser_create(), $source);
 549      }
 550      
 551      function known_encoding($enc) {
 552          $enc = strtoupper($enc);
 553          if ( in_array($enc, $this->_KNOWN_ENCODINGS) ) {
 554              return $enc;
 555          }
 556          else {
 557              return false;
 558          }
 559      }
 560  
 561      function error ($errormsg, $lvl=E_USER_WARNING) {
 562          // append PHP's error message if track_errors enabled
 563          if ( $php_errormsg ) { 
 564              $errormsg .= " ($php_errormsg)";
 565          }
 566          if ( MAGPIE_DEBUG ) {
 567              trigger_error( $errormsg, $lvl);        
 568          }
 569          else {
 570              error_log( $errormsg, 0);
 571          }
 572          
 573          $notices = E_USER_NOTICE|E_NOTICE;
 574          if ( $lvl&$notices ) {
 575              $this->WARNING = $errormsg;
 576          } else {
 577              $this->ERROR = $errormsg;
 578          }
 579      }
 580      
 581      
 582  } // end class RSS
 583  
 584  function map_attrs($k, $v) {
 585      return "$k=\"$v\"";
 586  }
 587  
 588  
 589  ?>