Refactor URL processing/generation into separate module

This is done to prepare for improved permalink generation
for URLs containing special characters, as proposed in
issue #782

lib/jekyll.rb

@@ -30,6 +30,7 @@ require 'pygments'
 require 'jekyll/core_ext'
 require 'jekyll/site'
 require 'jekyll/convertible'
+require 'jekyll/url'
 require 'jekyll/layout'
 require 'jekyll/page'
 require 'jekyll/post'

lib/jekyll/page.rb

@@ -1,6 +1,7 @@
 module Jekyll
   class Page
     include Convertible
+    include URL
 
     attr_writer :dir
     attr_accessor :site, :pager
@@ -69,28 +70,13 @@ module Jekyll
       end
     end
 
-    # The generated relative url of this page. e.g. /about.html.
+    # See url.rb for an explanation
-    #
+    def url_placeholders
-    # Returns the String url.
+      {
-    def url
+        "path"       => @dir,
-      return @url if @url
+        "basename"   => self.basename,
-
+        "output_ext" => self.output_ext
-      url = if permalink
+      }
-        permalink
-      else
-        {
-          "path"       => @dir,
-          "basename"   => self.basename,
-          "output_ext" => self.output_ext,
-        }.inject(template) { |result, token|
-          result.gsub(/:#{token.first}/, token.last)
-        }.gsub(/\/\//, "/")
-      end
-
-      # sanitize url
-      @url = url.split('/').reject{ |part| part =~ /^\.+$/ }.join('/')
-      @url += "/" if url =~ /\/$/
-      @url
     end
 
     # Extract information from the page filename.

lib/jekyll/post.rb

@@ -2,6 +2,7 @@ module Jekyll
   class Post
     include Comparable
     include Convertible
+    include URL
 
     class << self
       attr_accessor :lsi
@@ -153,36 +154,20 @@ module Jekyll
       end
     end
 
-    # The generated relative url of this post.
+    # See url.rb for an explanation
-    # e.g. /2008/11/05/my-awesome-post.html
+    def url_placeholders
-    #
+      {
-    # Returns the String URL.
+        "year"       => date.strftime("%Y"),
-    def url
+        "month"      => date.strftime("%m"),
-      return @url if @url
+        "day"        => date.strftime("%d"),
-
+        "title"      => CGI.escape(slug),
-      url = if permalink
+        "i_day"      => date.strftime("%d").to_i.to_s,
-        permalink
+        "i_month"    => date.strftime("%m").to_i.to_s,
-      else
+        "categories" => categories.map { |c| URI.escape(c.to_s) }.join('/'),
-        {
+        "short_month" => date.strftime("%b"),
-          "year"       => date.strftime("%Y"),
+        "y_day"      => date.strftime("%j"),
-          "month"      => date.strftime("%m"),
+        "output_ext" => self.output_ext
-          "day"        => date.strftime("%d"),
+      }
-          "title"      => CGI.escape(slug),
-          "i_day"      => date.strftime("%d").to_i.to_s,
-          "i_month"    => date.strftime("%m").to_i.to_s,
-          "categories" => categories.map { |c| URI.escape(c.to_s) }.join('/'),
-          "short_month" => date.strftime("%b"),
-          "y_day"      => date.strftime("%j"),
-          "output_ext" => self.output_ext
-        }.inject(template) { |result, token|
-          result.gsub(/:#{Regexp.escape token.first}/, token.last)
-        }.gsub(/\/\//, "/")
-      end
-
-      # sanitize url
-      @url = url.split('/').reject{ |part| part =~ /^\.+$/ }.join('/')
-      @url += "/" if url =~ /\/$/
-      @url
     end
 
     # The UID for this post (useful in feeds).

lib/jekyll/url.rb

@@ -0,0 +1,53 @@
+# The URL module provides methods that generate a URL for a resource in which they're
+# included, such as a Post or a Page.
+#
+# Requires
+#
+#   self.permalink  - If a permalink is set in the included instance, that permalink
+#                     will be returned instead of any URL that might've been generated
+#
+#   self.url_placeholders - Placeholders that may be used in the URL, which will be replaced
+#                         with the values when the URL is generated. Must return a Hash
+#                         mapping placeholder names to their values. For example, if this
+#                         method returned
+#
+#                           { "year" => Time.now.strftime("%Y") }
+#
+#                         Every occurrence of ":year" (note the colon) would be replaced with
+#                         the current year.
+#
+#
+
+module Jekyll
+  module URL
+
+    # The generated relative url of this page. e.g. /about.html.
+    #
+    # Returns the String url.
+    def url
+      @url ||= sanitize_url(permalink || generate_url)
+    end
+
+    # Generate the URL by replacing all placeholders with their respective values
+    #
+    # Returns the _unsanitizied_ String URL
+    def generate_url
+      url_placeholders.inject(template) { |result, token|
+        result.gsub(/:#{token.first}/, token.last)
+      }
+    end
+
+    # Returns a sanitized String URL
+    def sanitize_url(in_url)
+      # Remove all double slashes
+      url = in_url.gsub(/\/\//, "/")
+
+      # Remove every URL segment that consists solely of dots
+      url = url.split('/').reject{ |part| part =~ /^\.+$/ }.join('/')
+
+      # Append a trailing slash to the URL if the unsanitized URL had one
+      url += "/" if in_url =~ /\/$/
+      url
+    end
+  end
+end