Merge pull request #3 from gjtorikian/custom-filters

Add support for custom filters

README.md

@@ -54,3 +54,9 @@ html_pipeline:
 
 Keep in mind that [filter dependencies are not bundled](https://github.com/jch/html-pipeline#dependencies),
 so you'll need to add these in yourself.
+
+## Custom filters
+
+Custom filters can be designed [the same as in HTML::Pipeline](https://github.com/jch/html-pipeline#extending).
+
+Check out [the test filter](./test/support/new_pipeline.rb) for an example.

lib/jekyll-html-pipeline.rb

@@ -50,7 +50,12 @@ def setup
               key = filter_key(f)
               begin
                 filter = HTML::Pipeline.constants.find { |c| c.downcase == key }
-                HTML::Pipeline.const_get(filter)
+                # probably a custom filter
+                if filter.nil?
+                  Jekyll::Converters.const_get(f)
+                else
+                  HTML::Pipeline.const_get(filter)
+                end
               rescue Exception => e
                 raise LoadError.new(e)
               end

test/support/new_pipeline.rb

@@ -0,0 +1,15 @@
+require "html/pipeline"
+
+class HelpMarkdownFilter < HTML::Pipeline::MarkdownFilter
+
+  def call
+    html = super
+
+    format_callout!(html)
+  end
+
+  def format_callout!(html)
+    html.gsub!(/(?:<p>)?{{#(tip|warning|error)}}(?:<\/p>)?/,  '<div class="alert \1">')
+    html.gsub!(/(?:<p>)?{{\/(tip|warning|error)}}(?:<\/p>)?/, '</div>')
+  end
+end

test/test_jekyll_html_pipeline.rb

@@ -37,5 +37,14 @@ class HTMLPipeline < Test::Unit::TestCase
       markdown = Jekyll::Converters::Markdown.new override
       assert_raise(ArgumentError) { markdown.convert(':trollface:') }
     end
+
+    should "work for custom filters" do
+      require 'support/new_pipeline'
+      override = @config.dup
+      override['html_pipeline']['filters'] = ['HelpMarkdownFilter']
+      markdown = Jekyll::Converters::Markdown.new override
+      text = "\n {{#tip}}\n **Tip**: Wow! \n {{/tip}}"
+      assert_equal "<div class=\"alert tip\"><br>\n <strong>Tip</strong>: Wow! <br>\n </div>", markdown.convert(text)
+    end
   end
 end