diff --git a/app/helpers/gitlab_markdown_helper.rb b/app/helpers/gitlab_markdown_helper.rb index 89d2a648494..2f760af02fd 100644 --- a/app/helpers/gitlab_markdown_helper.rb +++ b/app/helpers/gitlab_markdown_helper.rb @@ -50,6 +50,8 @@ module GitlabMarkdownHelper context[:project] ||= @project + text = Banzai.pre_process(text, context) + html = Banzai.render(text, context) context.merge!( diff --git a/lib/banzai.rb b/lib/banzai.rb index 093382261ae..b467413a7dd 100644 --- a/lib/banzai.rb +++ b/lib/banzai.rb @@ -7,6 +7,10 @@ module Banzai Renderer.render_result(text, context) end + def self.pre_process(text, context) + Renderer.pre_process(text, context) + end + def self.post_process(html, context) Renderer.post_process(html, context) end diff --git a/lib/banzai/filter/yaml_front_matter_filter.rb b/lib/banzai/filter/yaml_front_matter_filter.rb new file mode 100644 index 00000000000..e4e2f3f228d --- /dev/null +++ b/lib/banzai/filter/yaml_front_matter_filter.rb @@ -0,0 +1,28 @@ +require 'html/pipeline/filter' +require 'yaml' + +module Banzai + module Filter + class YamlFrontMatterFilter < HTML::Pipeline::Filter + DELIM = '---'.freeze + + # Hat-tip to Middleman: https://git.io/v2e0z + PATTERN = %r{ + \A(?:[^\r\n]*coding:[^\r\n]*\r?\n)? + (?#{DELIM})[ ]*\r?\n + (?.*?)[ ]*\r?\n? + ^(?#{DELIM})[ ]*\r?\n? + \r?\n? + (?.*) + }mx.freeze + + def call + match = PATTERN.match(html) + + return html unless match + + "```yaml\n#{match['frontmatter']}\n```\n\n#{match['content']}" + end + end + end +end diff --git a/lib/banzai/pipeline/pre_process_pipeline.rb b/lib/banzai/pipeline/pre_process_pipeline.rb new file mode 100644 index 00000000000..50dc978b452 --- /dev/null +++ b/lib/banzai/pipeline/pre_process_pipeline.rb @@ -0,0 +1,17 @@ +module Banzai + module Pipeline + class PreProcessPipeline < BasePipeline + def self.filters + FilterArray[ + Filter::YamlFrontMatterFilter + ] + end + + def self.transform_context(context) + context.merge( + pre_process: true + ) + end + end + end +end diff --git a/lib/banzai/renderer.rb b/lib/banzai/renderer.rb index 891c0fd7749..ae714c87dc5 100644 --- a/lib/banzai/renderer.rb +++ b/lib/banzai/renderer.rb @@ -31,6 +31,12 @@ module Banzai Pipeline[context[:pipeline]].call(text, context) end + def self.pre_process(text, context) + pipeline = Pipeline[:pre_process] + + pipeline.to_html(text, context) + end + # Perform post-processing on an HTML String # # This method is used to perform state-dependent changes to a String of diff --git a/spec/lib/banzai/filter/yaml_front_matter_filter_spec.rb b/spec/lib/banzai/filter/yaml_front_matter_filter_spec.rb new file mode 100644 index 00000000000..fe70eada7eb --- /dev/null +++ b/spec/lib/banzai/filter/yaml_front_matter_filter_spec.rb @@ -0,0 +1,53 @@ +require 'rails_helper' + +describe Banzai::Filter::YamlFrontMatterFilter, lib: true do + include FilterSpecHelper + + it 'allows for `encoding:` before the frontmatter' do + content = <<-MD.strip_heredoc + # encoding: UTF-8 + --- + foo: foo + --- + + # Header + + Content + MD + + output = filter(content) + + expect(output).not_to match 'encoding' + end + + it 'converts YAML frontmatter to a fenced code block' do + content = <<-MD.strip_heredoc + --- + bar: :bar_symbol + --- + + # Header + + Content + MD + + output = filter(content) + + aggregate_failures do + expect(output).not_to include '---' + expect(output).to include "```yaml\nbar: :bar_symbol\n```" + end + end + + context 'on content without frontmatter' do + it 'returns the content unmodified' do + content = <<-MD.strip_heredoc + # This is some Markdown + + It has no YAML frontmatter to parse. + MD + + expect(filter(content)).to eq content + end + end +end