RSS feed for AlertBox

by Jon Gjengset

For those of you concerned with web usability, there are few better sources than Jakob Nielsen’s AlertBox.

Although his site is quite infrequently updated, it contains very informative posts. Unfortunately and ironically, the site does not have a RSS feed.

After an especially boring afternoon, I decided to see if I couldn’t do something about that, so with the use of this PHP Feed Generator class and some HTML parsing, I came up with the following script to generate an RSS feed from the AlertBox website:

Just download the FeedGenerator FeedWriter class from the given link, put the following code and FeedWriter.php in the same directory, upload it to a webserver with PHP support, and voilla, you have an AlertBox RSS feed.

Enjoy!

<?php

date_default_timezone_set("UTC");
class FetchAlertbox {
    private $contents = array();
    private function fetch() {
        $page = file_get_contents("http://www.useit.com/alertbox/index.html");
        $startList = stripos ( $page, '<ul>' );
        $page = substr ( $page, $startList, stripos ( $page, '</ul>', $startList ) - $startList + strlen ( '</ul>' ) );
        $page = str_ireplace ( '<p>', '', $page );
        $page = preg_replace ( "/<li>(.*)/i", '<li>$1</li>', $page );
        $page = preg_replace ( "@</?strong>@i", "", $page );
        $p = @DOMDocument::loadHTML($page);

        foreach ( $p->getElementsByTagName("li") as $article ) {
            $url = '';
            foreach ( $article->getElementsByTagName("a") as $link ) {
                if ( preg_match ( "@\w+.html@i", $link->getAttribute('href') ) ) {
                    $url = 'http://www.useit.com/alertbox/' . $link->getAttribute('href');
                    break;
                }
            }

            if ( $url === '' ) {
                continue;
            }

            $contents = str_replace ( "\n", " ", $article->textContent );
            $contents = preg_replace ( "/\s{2,}/", " ", $contents );
            $date = 0;
            $possibleStartDate = strrpos ( $contents, '(' );
            if ( $possibleStartDate !== false ) {
                $timestring = substr ( $contents, $possibleStartDate + 1, strpos ( $contents, ')', $possibleStartDate ) - $possibleStartDate - 1 );
                $parsedDate = strtotime ( $timestring );
                if ( $parsedDate !== false ) {
                    $date = $parsedDate;
                    $contents = str_replace ( "($timestring)", "", $contents );
                }
            }

            $this->contents[] = array ( 'url' => $url, 'title' => trim ( $contents ), 'date' => $date );
        }

        return $this->contents;
    }

    public function fetchWithSummaries($type = "RSS2", $limit = 10, $start = 0) {
        if ( empty ( $this->contents ) ) { $this->fetch(); }
        include ( "FeedWriter.php" );

        $feedType = RSS2;
        $feedDate = DATE_RSS;
        switch ( $type ) {
            case 'RSS1':
                $feedType = RSS1;
                break;
            case 'ATOM':
                $feedType = ATOM;
                $feedDate = DATE_ATOM;
                break;
        }

        $feed = new FeedWriter($feedType);
        $feed->setTitle("Alertbox");
        $feed->setLink("http://www.useit.com/alertbox/");
        $feed->setDescription("Current Issues in Web Usability - Bi-weekly column by Dr. Jakob Nielsen, principal, Nielsen Norman Group");

        if ( $type === 'ATOM' ) {
            $feed->setChannelElement('updated', date($feedDate, $this->contents[0]["date"]));
        } else {
            $feed->setChannelElement('pubDate', date($feedDate, $this->contents[0]["date"]));
        }

        $feed->setChannelElement('language', 'en-us');
        $feed->setChannelElement('author', array('name' => 'Dr. Jakob Nielsen'));

        if ( $type === "RSS1" ) {
            $feed->setChannelAboute("http://www.useit.com/alertbox/");
        }

        for ( $i = $start; $i < $start + $limit && $i < count ( $this->contents ); $i++ ) {
            $p = @DOMDocument::loadHTML ( file_get_contents ( $this->contents[$i]["url"] ) );
            $blockquotes = $p->getElementsByTagName("blockquote");
            if ( $blockquotes->length > 0 ) {
                $this->contents[$i]["summary"] = trim ( str_replace ( "Summary:", "", $blockquotes->item(0)->textContent ) );
            } else {
                $contents = $p->saveHTML();
                $endHeadline = stripos ( $contents, "</h1>" );
                $this->contents[$i]["summary"] = trim ( strip_tags ( substr ( $contents, $endHeadline + strlen ( "</h1>" ), stripos ( $contents, "<p>" ) - ( $endHeadline + strlen ( "</h1>" ) ) ) ) );
            }

            $item = $feed->createNewItem();
            $item->setTitle($this->contents[$i]["title"]);
            $item->setLink($this->contents[$i]["url"]);
            $item->setDate($this->contents[$i]["date"]);
            $item->setDescription($this->contents[$i]["summary"]);
            $feed->addItem($item);

//            echo date ( "F jS, Y", $this->contents[$i]["date"] ) . ": " . $this->contents[$i]["title"] . " -> " . $this->contents[$i]["url"] . "\n";
//            echo "\t" . $this->contents[$i]["summary"] . "\n\n";
        }

        $feed->genarateFeed();
    }
}

$s = new FetchAlertbox();
$s->fetchWithSummaries(isset($_GET['type']) ? strtoupper ( $_GET['type'] ) : 'RSS2', isset($_GET['limit']) && ctype_digit($_GET['limit']) ? $_GET['limit'] : 10);
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