Weekly Peace Vigil

<?php
/*
 * Project:     MagpieRSS: a simple RSS integration tool
 * File:        rss_parse.inc includes code for parsing
 *				RSS, and returning an RSS object
 * Author:      Kellan Elliott-McCrea <kellan@protest.net>
 * Version:		0.51
 * License:		GPL
 *
 * The lastest version of MagpieRSS can be obtained from:
 * http://magpierss.sourceforge.net
 *
 * For questions, help, comments, discussion, etc., please join the
 * Magpie mailing list:
 * magpierss-general@lists.sourceforge.net
 *
 */

/* 
 * NOTES ON RSS PARSING PHILOSOPHY (moderately important):
 * MagpieRSS parse all versions of RSS with a few limitation (mod_content, and
 * mod_taxonomy support is shaky) into a simple object, with 2 fields, 
 * the hash 'channel', and the array 'items'.
 *
 * MagpieRSS is a forgiving and inclusive parser.  It currently makes no
 * attempt to enforce the validity on an RSS feed.  It will include any
 * properly formatted tags it finds, allowing to you to mix RSS 0.93, with RSS
 * 1.0, with tags or your own imagining.  This sort of witches brew is a bad
 * bad idea!  But Magpie is less pendantic then I am.
 *
 * RSS validators are readily available on the web at:
 * http://feeds.archive.org/validator/
 * http://www.ldodds.com/rss_validator/1.0/validator.html
 *
 */

/*
 * EXAMPLE PARSE RESULTS:
 *
 * Magpie tries to parse RSS into ease to use PHP datastructures.
 *
 * For example, Magpie on encountering RSS 1.0 item entry:
 *
 * <item rdf:about="http://protest.net/NorthEast/calendrome.cgi?span=event&#38;ID=210257">
 * <title>Weekly Peace Vigil</title>
 * <link>http://protest.net/NorthEast/calendrome.cgi?span=event&#38;ID=210257</link>
 * <description>Wear a white ribbon</description>
 * <dc:subject>Peace</dc:subject>
 * <ev:startdate>2002-06-01T11:00:00</ev:startdate>
 * <ev:location>Northampton, MA</ev:location>
 * <ev:enddate>2002-06-01T12:00:00</ev:enddate>
 * <ev:type>Protest</ev:type>
 * </item>
 * 
 * Would transform it into the following associative array, and push it
 * onto the array $rss-items
 *
 * array(
 *	title => 'Weekly Peace Vigil',
 *	link =>
 *	'http://protest.net/NorthEast/calendrome.cgi?span=event&#38;ID=210257',
 *	description => 'Wear a white ribbon',
 *	dc => array (
 *			subject => 'Peace'
 *		),
 *	ev => array (
 *		startdate => '2002-06-01T11:00:00',
 *		enddate => '2002-06-01T12:00:00',
 *		type => 'Protest',
 *		location => 'Northampton, MA'
 *	)
 * )
 *
 */

class MagpieRSS {
    /*
	 * Hybrid parser, and object.  (probably a bad idea! :)
	 *
	 * Useage Example:
	 *
	 * $some_rss = "<?xml version="1.0"......
	 *
	 * $rss = new MagpieRSS( $some_rss );
	 *
	 * // print rss chanel title
	 * echo $rss->channel['title'];
	 *
	 * // print the title of each item
	 * foreach ($rss->items as $item ) {
	 *	  echo $item[title];
	 * }
	 *
	 * see rss_fetch.inc for a simpler interface
	 */

    var $parser;

    var $current_item = array(); // item currently being parsed
    var $items = array(); // collection of parsed items
    var $channel = array(); // hash of channel fields
    var $textinput = array();
    var $image = array();

    var $parent_field = array('RDF');
    var $current_field = '';
    var $current_namespace = false;

    var $ERROR = "";

    /*======================================================================*\
    Function: MagpieRSS
    Purpose:  Constructor, sets up XML parser,parses source,
			  and populates object.. 
	Input:	  String containing the RSS to be parsed
\*======================================================================*/
    function MagpieRSS ($source)
    { 
        // if PHP xml isn't compiled in, die
        
        if (!function_exists('xml_parser_create')) {
            $this->error("Failed to load PHP's XML Extension. " . "http://www.php.net/manual/en/ref.xml.php",
                E_USER_ERROR);
        } 

        $parser = @xml_parser_create();

        if (!is_resource($parser)) {
            $this->error("Failed to create an instance of PHP's XML parser. " . "http://www.php.net/manual/en/ref.xml.php",
                E_USER_ERROR);
        } 

        $this->parser = $parser; 
        // pass in parser, and a reference to this object
        // setup handlers
        
        xml_set_object($this->parser, $this);
        xml_set_element_handler($this->parser, 'start_element', 'end_element');
        xml_set_character_data_handler($this->parser, 'cdata');

        $status = xml_parse($this->parser, $source);

        if (! $status) {
            $errorcode = xml_get_error_code($this->parser);
            if ($errorcode != XML_ERROR_NONE) {
                $xml_error = xml_error_string($errorcode);
                $error_line = xml_get_current_line_number($this->parser);
                $error_col = xml_get_current_column_number($this->parser);
                $errormsg = "$xml_error at line $error_line, column $error_col";

                $this->error($errormsg);
            } 
        } 

        xml_parser_free($this->parser);
    } 

    function start_element ($p, $element, &$attrs)
    {
        $element = strtolower($element); 
        // check for a namespace, and split if found
        
        $namespace = false;
        if (strpos($element, ':')) {
            list($namespace, $element) = split(':', $element, 2);
        } 
        $this->current_field = $element;
        if ($namespace and $namespace != 'rdf') {
            $this->current_namespace = $namespace;
        } 

        if ($element == 'channel') {
            array_unshift($this->parent_field, 'channel');
        } elseif ($element == 'items') {
            array_unshift($this->parent_field, 'items');
        } elseif ($element == 'item') {
            array_unshift($this->parent_field, 'item');
        } elseif ($element == 'textinput') {
            array_unshift($this->parent_field, 'textinput');
        } elseif ($element == 'image') {
            array_unshift($this->parent_field, 'image');
        } 
    } 

    function end_element ($p, $element)
    {
        $element = strtolower($element);

        if ($element == 'item') {
            $this->items[] = $this->current_item;
            $this->current_item = array();
            array_shift($this->parent_field);
        } elseif ($element == 'channel' or $element == 'items' or
            $element == 'textinput' or $element == 'image') {
            array_shift($this->parent_field);
        } 

        $this->current_field = '';
        $this->current_namespace = false;
    } 

    function cdata ($p, $text)
    { 
        // skip item, channel, items first time we see them
        
        if ($this->parent_field[0] == $this->current_field or
            ! $this->current_field) {
            return;
        } elseif ($this->parent_field[0] == 'channel') {
            if ($this->current_namespace) {
                $this->append($this->channel[ $this->current_namespace ][ $this->current_field ],
                    $text);
            } else {
                $this->append($this->channel[ $this->current_field ], $text);
            } 
        } elseif ($this->parent_field[0] == 'item') {
            if ($this->current_namespace) {
                $this->append($this->current_item[ $this->current_namespace ][$this->current_field ],
                    $text);
            } else {
                $this->append($this->current_item[ $this->current_field ],
                    $text);
            } 
        } elseif ($this->parent_field[0] == 'textinput') {
            if ($this->current_namespace) {
                $this->append($this->textinput[ $this->current_namespace ][ $this->current_field ],
                    $text);
            } else {
                $this->append($this->textinput[ $this->current_field ],
                    $text);
            } 
        } elseif ($this->parent_field[0] == 'image') {
            if ($this->current_namespace) {
                $this->append($this->image[ $this->current_namespace ][ $this->current_field ],
                    $text);
            } else {
                $this->append($this->image[ $this->current_field ],
                    $text);
            } 
        } 
    } 

    function append (&$str1, $str2 = "")
    {
        if (!isset($str1)) {
            $str1 = "";
        } 
        $str1 .= $str2;
    } 

    function error ($errormsg, $lvl = E_USER_WARNING)
    { 
        // append PHP's error message if track_errors enabled
        if ($php_errormsg) {
            $errormsg .= " ($php_errormsg)";
        } 
        $this->ERROR = $errormsg;
        if (MAGPIE_DEBUG) {
            trigger_error($errormsg, $lvl);
        } else {
            error_log($errormsg, 0);
        } 
    } 

    /*======================================================================*\
	EVERYTHING BELOW HERE IS FOR DEBUGGING PURPOSES
\*======================================================================*/
    function show_list ()
    {
        echo "<ol>\n";
        foreach ($this->items as $item) {
            echo "<li>", $this->show_item($item);
        } 
        echo "</ol>";
    } 

    function show_channel ()
    {
        echo "channel:<br>";
        echo "<ul>";
        while (list($key, $value) = each($this->channel)) {
            echo "<li> $key: $value";
        } 
        echo "</ul>";
    } 

    function show_item ($item)
    {
        echo "item: $item[title]";
        echo "<ul>";
        while (list($key, $value) = each($item)) {
            if (is_array($value)) {
                echo "<br><b>$key</b>";
                echo "<ul>";
                while (list($ns_key, $ns_value) = each($value)) {
                    echo "<li>$ns_key: $ns_value";
                } 
                echo "</ul>";
            } else {
                echo "<li> $key: $value";
            } 
        } 
        echo "</ul>";
    } 

    /*======================================================================*\
	END DEBUGGING FUNCTIONS	
\*======================================================================*/

} # end class RSS

?>