Merge pull request #837 from ixti/feature-excerpt

Adds excerpt to posts

lib/jekyll.rb

@@ -74,6 +74,8 @@ module Jekyll
     'markdown_ext'  => 'markdown,mkd,mkdn,md',
     'textile_ext'   => 'textile',
 
+    'excerpt_separator' => "\n\n",
+
     'maruku' => {
       'use_tex'    => false,
       'use_divs'   => false,

lib/jekyll/post.rb

@@ -19,7 +19,7 @@ def self.valid?(name)
     end
 
     attr_accessor :site
-    attr_accessor :data, :content, :output, :ext
+    attr_accessor :data, :excerpt, :content, :output, :ext
     attr_accessor :date, :slug, :published, :tags, :categories
 
     attr_reader :name
@@ -77,8 +77,8 @@ def containing_dir(source, dir)
     # Returns nothing.
     def read_yaml(base, name)
       super(base, name)
+      self.excerpt = self.extract_excerpt
       self.data['layout'] = 'post' unless self.data.has_key?('layout')
-      self.data
     end
 
     # Compares Post objects. First compares the Post date. If the dates are
@@ -109,6 +109,14 @@ def process(name)
       raise FatalException.new("Post #{name} does not have a valid date.")
     end
 
+    # Transform the contents and excerpt based on the content type.
+    #
+    # Returns nothing.
+    def transform
+      super
+      self.excerpt = converter.convert(self.excerpt)
+    end
+
     # The generated directory into which the post will be placed
     # upon generation. This is derived from the permalink or, if
     # permalink is absent, set to the default date
@@ -257,7 +265,8 @@ def to_liquid
         "next"       => self.next,
         "previous"   => self.previous,
         "tags"       => self.tags,
-        "content"    => self.content })
+        "content"    => self.content,
+        "excerpt"    => self.excerpt })
     end
 
     # Returns the shorthand String identifier of this Post.
@@ -283,5 +292,48 @@ def previous
         nil
       end
     end
+
+    protected
+
+    # Internal: Extract excerpt from the content
+    #
+    # By default excerpt is your first paragraph of a post: everything before
+    # the first two new lines:
+    #
+    #     ---
+    #     title: Example
+    #     ---
+    #
+    #     First paragraph with [link][1].
+    #
+    #     Second paragraph.
+    #
+    #     [1]: http://example.com/
+    #
+    # This is fairly good option for Markdown and Textile files. But might cause
+    # problems for HTML posts (which is quite unusual for Jekyll). If default
+    # excerpt delimiter is not good for you, you might want to set your own via
+    # configuration option `excerpt_separator`. For example, following is a good
+    # alternative for HTML posts:
+    #
+    #     # file: _config.yml
+    #     excerpt_separator: "<!-- more -->"
+    #
+    # Notice that all markdown-style link references will be appended to the
+    # excerpt. So the example post above will have this excerpt source:
+    #
+    #     First paragraph with [link][1].
+    #
+    #     [1]: http://example.com/
+    #
+    # Excerpts are rendered same time as content is rendered.
+    #
+    # Returns excerpt String
+    def extract_excerpt
+      separator     = self.site.config['excerpt_separator']
+      head, _, tail = self.content.partition(separator)
+
+      "" << head << "\n\n" << tail.scan(/^\[[^\]]+\]:.+$/).join("\n")
+    end
   end
 end

test/source/_posts/2013-01-02-post-excerpt.markdown

@@ -0,0 +1,14 @@
+---
+layout: ~
+title:  Post Excerpt
+---
+
+First paragraph with [link ref][link].
+
+Second paragraph
+
+---
+
+Third paragraph
+
+[link]: http://www.jekyllrb.com/

test/test_generated_site.rb

@@ -14,7 +14,7 @@ class TestGeneratedSite < Test::Unit::TestCase
     end
 
     should "ensure post count is as expected" do
-      assert_equal 30, @site.posts.size
+      assert_equal 31, @site.posts.size
     end
 
     should "insert site.posts into the index" do

test/test_post.rb

@@ -252,6 +252,52 @@ def do_render(post)
 
         assert_equal "<h1>{{ page.title }}</h1>\n<p>Best <strong>post</strong> ever</p>", @post.content
       end
+
+      context "#excerpt" do
+        setup do
+          file = "2013-01-02-post-excerpt.markdown"
+          @post.process(file)
+          @post.read_yaml(@source, file)
+          @post.transform
+        end
+
+        should "return first paragraph by default" do
+          assert @post.excerpt.include?("First paragraph"), "contains first paragraph"
+          assert !@post.excerpt.include?("Second paragraph"), "does not contains second paragraph"
+          assert !@post.excerpt.include?("Third paragraph"), "does not contains third paragraph"
+        end
+
+        should "correctly resolve link references" do
+          assert @post.excerpt.include?("www.jekyllrb.com"), "contains referenced link URL"
+        end
+
+        should "return rendered HTML" do
+          assert_equal "<p>First paragraph with <a href='http://www.jekyllrb.com/'>link ref</a>.</p>",
+                       @post.excerpt
+        end
+
+        context "with excerpt_separator setting" do
+          setup do
+            file = "2013-01-02-post-excerpt.markdown"
+
+            @post.site.config['excerpt_separator'] = "\n---\n"
+
+            @post.process(file)
+            @post.read_yaml(@source, file)
+            @post.transform
+          end
+
+          should "respect given separator" do
+            assert @post.excerpt.include?("First paragraph"), "contains first paragraph"
+            assert @post.excerpt.include?("Second paragraph"), "contains second paragraph"
+            assert !@post.excerpt.include?("Third paragraph"), "does not contains third paragraph"
+          end
+
+          should "replace separator with new-lines" do
+            assert !@post.excerpt.include?("---"), "does not contains separator"
+          end
+        end
+      end
     end
 
     context "when in a site" do