Attempt to fix project rendering for images

app/controllers/concerns/markdown_renderable.rb

@@ -2,11 +2,42 @@ module MarkdownRenderable
   extend ActiveSupport::Concern
 
   class_methods do
-    def render_markdown(text)
+    def render_markdown(text, user = nil, project_name = nil)
       return "" if text.blank?
 
-      @markdown_renderer ||= Redcarpet::Markdown.new(
-        Redcarpet::Render::HTML,
+      renderer = if user && project_name
+                  Class.new(Redcarpet::Render::HTML) do
+                    def initialize(user, project_name)
+                      @user = user
+                      @project_name = project_name
+                      super()
+                    end
+
+                    def image(link, title, alt_text)
+                      # If the link is a relative path, rewrite it
+                      unless link =~ %r{^https?://}
+                        link = "/projects/#{@user}/#{@project_name}/#{link}"
+                      end
+                      "<img src=\"#{link}\" alt=\"#{alt_text}\" title=\"#{title}\">"
+                    end
+
+                    def postprocess(full_document)
+                      # Only rewrite src attributes in img tags that don't already have the project path
+                      full_document.gsub(/<img[^>]+src="([^"]+)"[^>]*>/) do |match|
+                        src = $1
+                        unless src =~ %r{^https?://} || src.start_with?("/projects/#{@user}/#{@project_name}/")
+                          src = "/projects/#{@user}/#{@project_name}/#{src}"
+                        end
+                        match.gsub(/src="[^"]+"/, "src=\"#{src}\"")
+                      end
+                    end
+                  end.new(user, project_name)
+      else
+                  Redcarpet::Render::HTML
+      end
+
+      markdown = Redcarpet::Markdown.new(
+        renderer,
         autolink: true,
         tables: true,
         fenced_code_blocks: true,
@@ -18,13 +49,13 @@ module MarkdownRenderable
         footnotes: true
       )
 
-      @markdown_renderer.render(text).html_safe
+      markdown.render(text).html_safe
     end
   end
 
   private
 
-  def render_markdown(text)
-    self.class.render_markdown(text)
+  def render_markdown(text, user = nil, project_name = nil)
+    self.class.render_markdown(text, user, project_name)
   end
 end

app/models/project.rb

@@ -135,7 +135,7 @@ class Project
       author: metadata["author"],
       description: metadata["description"],
       created_at: metadata["created_at"],
-      content: render_markdown(markdown_content)
+      content: render_markdown(markdown_content, user, project_name)
     )
   end
 end

public/projects

@@ -0,0 +1 @@
+../content/projects