Returns the episode titles a certain American Podcast series

composer.json

{
    "require":
        {
        "symfony/dom-crawler": "2.2.x-dev",
        "symfony/css-selector": "2.2.x-dev"
    }
}

scrape.php

<?php

require('vendor/autoload.php');

use Symfony\Component\DomCrawler\Crawler;

$mainPage = downloadPage('http://www.thisamericanlife.org/radio-archives');
$crawler = new Crawler($mainPage);

$baseUrl   = "http://www.thisamericanlife.org";
$episodes  = array();
$urlsToScrape = array();

// Read the contents of the Navigation bar so we know which pages to download.
$yearNodes = $crawler->filter('#archive-date-nav li a')->reduce(function($node, $i) {});
foreach($yearNodes as $yearNode) {
    $urlsToScrape[] = $baseUrl . $yearNode->getAttribute('href');
}

// Go through each archived Year and pull out the episode titles.
foreach ($urlsToScrape as $url) {
    $page = downloadPage($url);
    $crawler = new Crawler($page);

    $showNodes = $crawler->filter('.episode-archive > h3 a')->reduce(function($node, $i) {});

    // Read the episode title for the shows.
    foreach($showNodes as $showNode) {
        $bits = explode(':', $showNode->nodeValue);
        $epNum = $bits[0];
        $episodes[$epNum] = $showNode->nodeValue;
    }
}

ksort($episodes);
foreach ($episodes as $episode) {
    echo $episode . PHP_EOL;
}

function downloadPage($url) {
    // Simple caching.
    $cacheDir = 'cache';
    $cacheExpiry = 60 * 60 * 24 * 7; // One week
    $urlHash = sha1($url);

    $cacheFile = $cacheDir . '/' . $urlHash;

    if (!file_exists($cacheDir)) {
        mkdir($cacheDir);
    }

    if(file_exists($cacheFile) && (time() - filemtime($cacheFile)) < $cacheExpiry){
        return file_get_contents($cacheFile);
    } else {
        $page = file_get_contents($url);
        file_put_contents($cacheFile, $page);
        return $page;
    }

}