1 files changed, 76 insertions, 0 deletions
diff --git a/lib/banzai/renderer.rb b/lib/banzai/renderer.rb
new file mode 100644
index 00000000000..891c0fd7749
--- /dev/null
+++ b/lib/banzai/renderer.rb
@@ -0,0 +1,76 @@
+module Banzai
+  module Renderer
+    # Convert a Markdown String into an HTML-safe String of HTML
+    #
+    # Note that while the returned HTML will have been sanitized of dangerous
+    # HTML, it may post a risk of information leakage if it's not also passed
+    # through `post_process`.
+    #
+    # Also note that the returned String is always HTML, not XHTML. Views
+    # requiring XHTML, such as Atom feeds, need to call `post_process` on the
+    # result, providing the appropriate `pipeline` option.
+    #
+    # markdown - Markdown String
+    # context  - Hash of context options passed to our HTML Pipeline
+    #
+    # Returns an HTML-safe String
+    def self.render(text, context = {})
+      cache_key = context.delete(:cache_key)
+      cache_key = full_cache_key(cache_key, context[:pipeline])
+
+      if cache_key
+        Rails.cache.fetch(cache_key) do
+          cacheless_render(text, context)
+        end
+      else
+        cacheless_render(text, context)
+      end
+    end
+
+    def self.render_result(text, context = {})
+      Pipeline[context[:pipeline]].call(text, context)
+    end
+
+    # Perform post-processing on an HTML String
+    #
+    # This method is used to perform state-dependent changes to a String of
+    # HTML, such as removing references that the current user doesn't have
+    # permission to make (`RedactorFilter`).
+    #
+    # html     - String to process
+    # context  - Hash of options to customize output
+    #            :pipeline  - Symbol pipeline type
+    #            :project   - Project
+    #            :user      - User object
+    #
+    # Returns an HTML-safe String
+    def self.post_process(html, context)
+      context = Pipeline[context[:pipeline]].transform_context(context)
+
+      pipeline = Pipeline[:post_process]
+      if context[:xhtml]
+        pipeline.to_document(html, context).to_html(save_with: Nokogiri::XML::Node::SaveOptions::AS_XHTML)
+      else
+        pipeline.to_html(html, context)
+      end.html_safe
+    end
+
+    private
+
+    def self.cacheless_render(text, context = {})
+      result = render_result(text, context)
+
+      output = result[:output]
+      if output.respond_to?(:to_html)
+        output.to_html
+      else
+        output.to_s
+      end
+    end
+
+    def self.full_cache_key(cache_key, pipeline_name)
+      return unless cache_key
+      ["banzai", *cache_key, pipeline_name || :full]
+    end
+  end
+end