Added support for pagination with a blog index in any directory (helps with landing pages). Added configuration for pagination directory base

3 files changed, 162 insertions, 3 deletions

diff --git a/.themes/classic/source/index.html b/.themes/classic/source/index.html
index fa5310a9..e7e96956 100644
--- a/.themes/classic/source/index.html
+++ b/.themes/classic/source/index.html
@@ -2,4 +2,41 @@
 layout: default
 ---
 
-{% include blog_index.html %}
+<div class="blog-index">
+{% assign index = true %}
+{% for post in paginator.posts %}
+{% assign content = post.content %}
+  <article>
+    {% include article.html %}
+  </article>
+{% endfor %}
+<nav role="pagination">
+  <div>
+    {% if paginator.next_page %}
+      <a class="prev" href="{{paginator.next_page}}">&larr; Older</a>
+    {% endif %}
+    <a href="/blog/archives">Blog Archives</a>
+    {% if paginator.previous_page %}
+    <a class="next" href="{{paginator.previous_page}}">Newer &rarr;</a>
+    {% endif %}
+  </div>
+</nav>
+{% if site.disqus_short_name %}
+<script type="text/javascript">
+    var disqus_shortname = '{{ site.disqus_short_name }}';
+    (function () {
+      var s = document.createElement('script'); s.async = true;
+      s.type = 'text/javascript';
+      s.src = 'http://' + disqus_shortname + '.disqus.com/count.js';
+      (document.getElementsByTagName('HEAD')[0] || document.getElementsByTagName('BODY')[0]).appendChild(s);
+    }());
+</script>
+{% endif %}
+</div>
+<aside role=sidebar>
+  {% if site.blog_index_asides.size %}
+    {% include_array blog_index_asides %}
+  {% else %}
+    {% include_array default_asides %}
+  {% endif %}
+</aside>
diff --git a/_config.yml b/_config.yml
index 3d6fee89..403f9ba8 100644
--- a/_config.yml
+++ b/_config.yml
@@ -29,8 +29,9 @@ category_dir: blog/categories
 markdown: rdiscount
 pygments: false # default python pygments have been replaced by pygments.rb
 
-paginate: 10 # Posts per page on the blog index
-recent_posts: 5 # Posts in the sidebar Recent Posts section
+paginate: 10          # Posts per page on the blog index
+pagination_dir: blog  # Directory base for pagination URLs eg. /blog/page/2/
+recent_posts: 5       # Posts in the sidebar Recent Posts section
 
 # list each of the sidebar modules you want to include, in the order you want them to appear.
 # To add custom asides, create files in /source/_includes/custom/asides/ and add them to the list like 'custom/asides/custom_aside_name.html'
diff --git a/plugins/pagination.rb b/plugins/pagination.rb
new file mode 100644
index 00000000..001ddd47
--- /dev/null
+++ b/plugins/pagination.rb
@@ -0,0 +1,121 @@
+module Jekyll
+
+  class Pagination < Generator
+    # This generator is safe from arbitrary code execution.
+    safe true
+
+    # Generate paginated pages if necessary.
+    #
+    # site - The Site.
+    #
+    # Returns nothing.
+    def generate(site)
+      site.pages.dup.each do |page|
+        paginate(site, page) if Pager.pagination_enabled?(site.config, page)
+      end
+    end
+
+    # Paginates the blog's posts. Renders the index.html file into paginated
+    # directories, e.g.: page2/index.html, page3/index.html, etc and adds more
+    # site-wide data.
+    #
+    # site - The Site.
+    # page - The index.html Page that requires pagination.
+    #
+    # {"paginator" => { "page" => <Number>,
+    #                   "per_page" => <Number>,
+    #                   "posts" => [<Post>],
+    #                   "total_posts" => <Number>,
+    #                   "total_pages" => <Number>,
+    #                   "previous_page" => <Number>,
+    #                   "next_page" => <Number> }}
+    def paginate(site, page)
+      all_posts = site.site_payload['site']['posts']
+      pages = Pager.calculate_pages(all_posts, site.config['paginate'].to_i)
+      page_dir = page.destination('').sub(/\/[^\/]+$/, '')
+      page_dir_config = site.config['pagination_dir']
+      dir = ((page_dir_config || page_dir) + '/').sub(/^\/+/, '')
+
+      (1..pages).each do |num_page|
+        pager = Pager.new(site.config, num_page, all_posts, pages, page_dir+'/', '/'+dir)
+        if num_page > 1
+          newpage = Page.new(site, site.source, page_dir, page.name)
+          newpage.pager = pager
+          newpage.dir = File.join(page.dir, "#{dir}page/#{num_page}")
+          site.pages << newpage
+        else
+          page.pager = pager
+        end
+      end
+    end
+  end
+
+  class Pager
+    attr_reader :page, :per_page, :posts, :total_posts, :total_pages, :previous_page, :next_page
+
+    # Calculate the number of pages.
+    #
+    # all_posts - The Array of all Posts.
+    # per_page  - The Integer of entries per page.
+    #
+    # Returns the Integer number of pages.
+    def self.calculate_pages(all_posts, per_page)
+      (all_posts.size.to_f / per_page.to_i).ceil
+    end
+
+    # Determine if pagination is enabled for a given file.
+    #
+    # config - The configuration Hash.
+    # file   - The String filename of the file.
+    #
+    # Returns true if pagination is enabled, false otherwise.
+    def self.pagination_enabled?(config, file)
+      file.name == 'index.html' && !config['paginate'].nil? && file.content =~ /paginator\./
+    end
+
+    # Initialize a new Pager.
+    #
+    # config    - The Hash configuration of the site.
+    # page      - The Integer page number.
+    # all_posts - The Array of all the site's Posts.
+    # num_pages - The Integer number of pages or nil if you'd like the number
+    #             of pages calculated.
+    def initialize(config, page, all_posts, num_pages = nil, index_dir, pagination_dir)
+      @page = page
+      @per_page = config['paginate'].to_i
+      @page_dir = pagination_dir + 'page/'
+      @total_pages = num_pages || Pager.calculate_pages(all_posts, @per_page)
+      @previous_page = nil
+
+      if @page > @total_pages
+        raise RuntimeError, "page number can't be greater than total pages: #{@page} > #{@total_pages}"
+      end
+
+      init = (@page - 1) * @per_page
+      offset = (init + @per_page - 1) >= all_posts.size ? all_posts.size : (init + @per_page - 1)
+
+      @total_posts = all_posts.size
+      @posts = all_posts[init..offset]
+      @previous_page = @page != 1 ? @page_dir + (@page - 1).to_s + '/' : nil
+      @previous_page = index_dir if @page - 1 == 1
+      @next_page = @page != @total_pages ? @page_dir + (@page + 1).to_s + '/' : nil
+    end
+
+    # Convert this Pager's data to a Hash suitable for use by Liquid.
+    #
+    # Returns the Hash representation of this Pager.
+    def to_liquid
+      {
+        'page' => page,
+        'per_page' => per_page,
+        'posts' => posts,
+        'total_posts' => total_posts,
+        'total_pages' => total_pages,
+        'previous_page' => previous_page,
+        'next_page' => next_page
+      }
+    end
+  end
+
+end
+