kemal/src/kemal/static_file_handler.cr

{% if !flag?(:without_zlib) %}
  require "zlib"
{% end %}

module Kemal
  class StaticFileHandler < HTTP::StaticFileHandler
    def call(context : HTTP::Server::Context)
      return call_next(context) if context.request.path.not_nil! == "/"

      unless context.request.method == "GET" || context.request.method == "HEAD"
        if @fallthrough
          call_next(context)
        else
          context.response.status_code = 405
          context.response.headers.add("Allow", "GET, HEAD")
        end
        return
      end

      config = Kemal.config.serve_static
      original_path = context.request.path.not_nil!
      is_dir_path = original_path.ends_with? "/"
      request_path = URI.unescape(original_path)

      # File path cannot contains '\0' (NUL) because all filesystem I know
      # don't accept '\0' character as file name.
      if request_path.includes? '\0'
        context.response.status_code = 400
        return
      end

      expanded_path = File.expand_path(request_path, "/")
      if is_dir_path && !expanded_path.ends_with? "/"
        expanded_path = "#{expanded_path}/"
      end
      is_dir_path = expanded_path.ends_with? "/"

      file_path = File.join(@public_dir, expanded_path)
      is_dir = Dir.exists? file_path

      if request_path != expanded_path || is_dir && !is_dir_path
        redirect_to context, "#{expanded_path}#{is_dir && !is_dir_path ? "/" : ""}"
      end

      if Dir.exists?(file_path)
        if config.is_a?(Hash) && config["dir_listing"] == true
          context.response.content_type = "text/html"
          directory_listing(context.response, request_path, file_path)
        else
          return call_next(context)
        end
      elsif File.exists?(file_path)
        last_modified = modification_time(file_path)
        add_cache_headers(context.response.headers, last_modified)

        if cache_request?(context, last_modified)
          context.response.status_code = 304
          return
        end
        send_file(context, file_path)
      else
        call_next(context)
      end
    end
  end
end