aggregator.parser.inc

<?php


/**
 * @file
 * Parser functions for the aggregator module.
 */

/**
 * Implements hook_aggregator_parse_info().
 */
function aggregator_aggregator_parse_info() {
    return array(
        'title' => t('Default parser'),
        'description' => t('Parses RSS, Atom and RDF feeds.'),
    );
}

/**
 * Implements hook_aggregator_parse().
 */
function aggregator_aggregator_parse($feed) {
    global $channel, $image;
    // Filter the input data.
    if (aggregator_parse_feed($feed->source_string, $feed)) {
        $modified = empty($feed->http_headers['last-modified']) ? 0 : strtotime($feed->http_headers['last-modified']);
        // Prepare the channel data.
        foreach ($channel as $key => $value) {
            $channel[$key] = trim($value);
        }
        // Prepare the image data (if any).
        foreach ($image as $key => $value) {
            $image[$key] = trim($value);
        }
        $etag = empty($feed->http_headers['etag']) ? '' : $feed->http_headers['etag'];
        // Add parsed data to the feed object.
        $feed->link = !empty($channel['link']) ? $channel['link'] : '';
        $feed->description = !empty($channel['description']) ? $channel['description'] : '';
        $feed->image = !empty($image['url']) ? $image['url'] : '';
        $feed->etag = $etag;
        $feed->modified = $modified;
        // Clear the cache.
        cache_clear_all();
        return TRUE;
    }
    return FALSE;
}

/**
 * Parses a feed and stores its items.
 *
 * @param $data
 *   The feed data.
 * @param $feed
 *   An object describing the feed to be parsed.
 *
 * @return
 *   FALSE on error, TRUE otherwise.
 */
function aggregator_parse_feed(&$data, $feed) {
    global $items, $image, $channel;
    // Unset the global variables before we use them.
    unset($GLOBALS['element'], $GLOBALS['item'], $GLOBALS['tag']);
    $items = array();
    $image = array();
    $channel = array();
    // Parse the data.
    $xml_parser = drupal_xml_parser_create($data);
    xml_set_element_handler($xml_parser, 'aggregator_element_start', 'aggregator_element_end');
    xml_set_character_data_handler($xml_parser, 'aggregator_element_data');
    if (!xml_parse($xml_parser, $data, 1)) {
        watchdog('aggregator', 'The feed from %site seems to be broken, due to an error "%error" on line %line.', array(
            '%site' => $feed->title,
            '%error' => xml_error_string(xml_get_error_code($xml_parser)),
            '%line' => xml_get_current_line_number($xml_parser),
        ), WATCHDOG_WARNING);
        drupal_set_message(t('The feed from %site seems to be broken, because of error "%error" on line %line.', array(
            '%site' => $feed->title,
            '%error' => xml_error_string(xml_get_error_code($xml_parser)),
            '%line' => xml_get_current_line_number($xml_parser),
        )), 'error');
        return FALSE;
    }
    xml_parser_free($xml_parser);
    // We reverse the array such that we store the first item last, and the last
    // item first. In the database, the newest item should be at the top.
    $items = array_reverse($items);
    // Initialize items array.
    $feed->items = array();
    foreach ($items as $item) {
        // Prepare the item:
        foreach ($item as $key => $value) {
            $item[$key] = trim($value);
        }
        // Resolve the item's title. If no title is found, we use up to 40
        // characters of the description ending at a word boundary, but not
        // splitting potential entities.
        if (!empty($item['title'])) {
            $item['title'] = $item['title'];
        }
        elseif (!empty($item['description'])) {
            $item['title'] = preg_replace('/^(.*)[^\\w;&].*?$/', "\\1", truncate_utf8($item['description'], 40));
        }
        else {
            $item['title'] = '';
        }
        // Resolve the items link.
        if (!empty($item['link'])) {
            $item['link'] = $item['link'];
        }
        else {
            $item['link'] = $feed->link;
        }
        // Atom feeds have an ID tag instead of a GUID tag.
        if (!isset($item['guid'])) {
            $item['guid'] = isset($item['id']) ? $item['id'] : '';
        }
        // Atom feeds have a content and/or summary tag instead of a description tag.
        if (!empty($item['content:encoded'])) {
            $item['description'] = $item['content:encoded'];
        }
        elseif (!empty($item['summary'])) {
            $item['description'] = $item['summary'];
        }
        elseif (!empty($item['content'])) {
            $item['description'] = $item['content'];
        }
        // Try to resolve and parse the item's publication date.
        $date = '';
        foreach (array(
            'pubdate',
            'dc:date',
            'dcterms:issued',
            'dcterms:created',
            'dcterms:modified',
            'issued',
            'created',
            'modified',
            'published',
            'updated',
        ) as $key) {
            if (!empty($item[$key])) {
                $date = $item[$key];
                break;
            }
        }
        $item['timestamp'] = strtotime($date);
        if ($item['timestamp'] === FALSE) {
            $item['timestamp'] = aggregator_parse_w3cdtf($date);
            // Aggregator_parse_w3cdtf() returns FALSE on failure.
        }
        // Resolve dc:creator tag as the item author if author tag is not set.
        if (empty($item['author']) && !empty($item['dc:creator'])) {
            $item['author'] = $item['dc:creator'];
        }
        $item += array(
            'author' => '',
            'description' => '',
        );
        // Store on $feed object. This is where processors will look for parsed items.
        $feed->items[] = $item;
    }
    return TRUE;
}

/**
 * Performs an action when an opening tag is encountered.
 *
 * Callback function used by xml_parse() within aggregator_parse_feed().
 */
function aggregator_element_start($parser, $name, $attributes) {
    global $item, $element, $tag, $items, $channel;
    $name = strtolower($name);
    switch ($name) {
        case 'image':
        case 'textinput':
        case 'summary':
        case 'tagline':
        case 'subtitle':
        case 'logo':
        case 'info':
            $element = $name;
            break;
        case 'id':
        case 'content':
            if ($element != 'item') {
                $element = $name;
            }
        case 'link':
            // According to RFC 4287, link elements in Atom feeds without a 'rel'
            // attribute should be interpreted as though the relation type is
            // "alternate".
            if (!empty($attributes['HREF']) && (empty($attributes['REL']) || $attributes['REL'] == 'alternate')) {
                if ($element == 'item') {
                    $items[$item]['link'] = $attributes['HREF'];
                }
                else {
                    $channel['link'] = $attributes['HREF'];
                }
            }
            break;
        case 'item':
            $element = $name;
            $item += 1;
            break;
        case 'entry':
            $element = 'item';
            $item += 1;
            break;
    }
    $tag = $name;
}

/**
 * Performs an action when a closing tag is encountered.
 *
 * Callback function used by xml_parse() within aggregator_parse_feed().
 */
function aggregator_element_end($parser, $name) {
    global $element;
    switch ($name) {
        case 'image':
        case 'textinput':
        case 'item':
        case 'entry':
        case 'info':
            $element = '';
            break;
        case 'id':
        case 'content':
            if ($element == $name) {
                $element = '';
            }
    }
}

/**
 * Performs an action when data is encountered.
 *
 * Callback function used by xml_parse() within aggregator_parse_feed().
 */
function aggregator_element_data($parser, $data) {
    global $channel, $element, $items, $item, $image, $tag;
    $items += array(
        $item => array(),
    );
    switch ($element) {
        case 'item':
            $items[$item] += array(
                $tag => '',
            );
            $items[$item][$tag] .= $data;
            break;
        case 'image':
        case 'logo':
            $image += array(
                $tag => '',
            );
            $image[$tag] .= $data;
            break;
        case 'link':
            if ($data) {
                $items[$item] += array(
                    $tag => '',
                );
                $items[$item][$tag] .= $data;
            }
            break;
        case 'content':
            $items[$item] += array(
                'content' => '',
            );
            $items[$item]['content'] .= $data;
            break;
        case 'summary':
            $items[$item] += array(
                'summary' => '',
            );
            $items[$item]['summary'] .= $data;
            break;
        case 'tagline':
        case 'subtitle':
            $channel += array(
                'description' => '',
            );
            $channel['description'] .= $data;
            break;
        case 'info':
        case 'id':
        case 'textinput':
            // The sub-element is not supported. However, we must recognize
            // it or its contents will end up in the item array.
            break;
        default:
            $channel += array(
                $tag => '',
            );
            $channel[$tag] .= $data;
    }
}

/**
 * Parses the W3C date/time format, a subset of ISO 8601.
 *
 * PHP date parsing functions do not handle this format. See
 * http://www.w3.org/TR/NOTE-datetime for more information. Originally from
 * MagpieRSS (http://magpierss.sourceforge.net/).
 *
 * @param $date_str
 *   A string with a potentially W3C DTF date.
 *
 * @return
 *   A timestamp if parsed successfully or FALSE if not.
 */
function aggregator_parse_w3cdtf($date_str) {
    if (preg_match('/(\\d{4})-(\\d{2})-(\\d{2})T(\\d{2}):(\\d{2})(:(\\d{2}))?(?:([-+])(\\d{2}):?(\\d{2})|(Z))?/', $date_str, $match)) {
        list($year, $month, $day, $hours, $minutes, $seconds) = array(
            $match[1],
            $match[2],
            $match[3],
            $match[4],
            $match[5],
            $match[6],
        );
        // Calculate the epoch for current date assuming GMT.
        $epoch = gmmktime($hours, $minutes, $seconds, $month, $day, $year);
        if ($match[10] != 'Z') {
            // Z is zulu time, aka GMT
            list($tz_mod, $tz_hour, $tz_min) = array(
                $match[8],
                $match[9],
                $match[10],
            );
            // Zero out the variables.
            if (!$tz_hour) {
                $tz_hour = 0;
            }
            if (!$tz_min) {
                $tz_min = 0;
            }
            $offset_secs = ($tz_hour * 60 + $tz_min) * 60;
            // Is timezone ahead of GMT?  If yes, subtract offset.
            if ($tz_mod == '+') {
                $offset_secs *= -1;
            }
            $epoch += $offset_secs;
        }
        return $epoch;
    }
    else {
        return FALSE;
    }
}