crawler_ebook.php

<?php

define('BASE_URL', 'http://chimera.labs.oreilly.com/books/1230000000545/');

function getPage($url)
{
    $full_url = BASE_URL . $url;
    echo "Crawleando página $full_url...", PHP_EOL;
    $file = __DIR__ . '/ebook/'. $url;
    file_put_contents($file, file_get_contents($full_url));
    $page = @DOMDocument::loadHTMLFile($file);
    getNextUrl($page);
}

function getNextUrl($page)
{
    $xpath = new DOMXpath($page);
    getImages($page);
    $next_url = $xpath->query('//a[@accesskey="n"]');
    foreach ($next_url as $x) {
        $next_url = $x->getAttribute('href');
        break;
    }
    getPage($next_url);
}

function getImages($page)
{
    $xpath = new DOMXpath($page);
    $images = $xpath->query('//img');

    foreach ($images as $image) {
        $image_source = $image->getAttribute('src');
        $basename_file = basename($image_source);
        echo "Baixando a imagem $image_source", PHP_EOL;
        file_put_contents(__DIR__ . '/ebook/images/' . $basename_file, file_get_contents($image_source));
    }
}

getPage('/pr01.html');

This was made in 15min. Don't take it seriously.