class StaticRails::FileHandler
This class was extracted from Ruby on Rails:
- actionpack/lib/action_dispatch/middleware/static.rb
Copyright © 2005-2020 David Heinemeier Hansson, Ryan Edward Hall, Jeremy Daer
License here: github.com/rails/rails/blob/master/MIT-LICENSE
This endpoint serves static files from disk using Rack::File.
URL paths are matched with static files according to expected conventions: path
, path
.html, path
/index.html.
Precompressed versions of these files are checked first. Brotli (.br) and gzip (.gz) files are supported. If path
.br exists, this endpoint returns that file with a +Content-Encoding: br+ header.
If no matching file is found, this endpoint responds 404 Not Found.
Pass the root
directory to search for matching files, an optional +index: “index”+ to change the default path
/index.html, and optional additional response headers.
Constants
- PRECOMPRESSED
Accept-Encoding value -> file extension
Public Class Methods
# File lib/static-rails/file_handler.rb, line 32 def initialize(root, index: "index", headers: {}, precompressed: %i[br gzip], compressible_content_types: /\A(?:text\/|application\/javascript)/) @root = root.chomp("/").b @index = index @precompressed = Array(precompressed).map(&:to_s) | %w[identity] @compressible_content_types = compressible_content_types @file_server = ::Rack::File.new(@root, headers) end
Public Instance Methods
# File lib/static-rails/file_handler.rb, line 46 def attempt(env) request = Rack::Request.new env if request.get? || request.head? if (found = find_file(request.path_info, accept_encoding: request.accept_encoding)) serve request, *found end end end
# File lib/static-rails/file_handler.rb, line 42 def call(env) attempt(env) || @file_server.call(env) end
Match a URI path to a static file to be served.
Used by the Static
class to negotiate a servable file in the public/
directory (see Static#call).
Checks for path
, path
.html, and path
/index.html files, in that order, including .br and .gzip compressed extensions.
If a matching file is found, the path and necessary response headers (Content-Type, Content-Encoding) are returned.
# File lib/static-rails/file_handler.rb, line 79 def find_file(path_info, accept_encoding:) each_candidate_filepath(path_info) do |filepath, content_type| if (response = try_files(filepath, content_type, accept_encoding: accept_encoding)) return response end end end
# File lib/static-rails/file_handler.rb, line 56 def serve(request, filepath, content_headers) original, request.path_info = request.path_info, ::Rack::Utils.escape_path(filepath).b @file_server.call(request.env).tap do |status, headers, body| # Omit Content-Encoding/Type/etc headers for 304 Not Modified if status != 304 headers.update(content_headers) end end ensure request.path_info = original end
Private Instance Methods
# File lib/static-rails/file_handler.rb, line 165 def clean_path(path_info) path = ::Rack::Utils.unescape_path path_info.chomp("/") if ::Rack::Utils.valid_path? path ::Rack::Utils.clean_path_info path end end
# File lib/static-rails/file_handler.rb, line 129 def compressible?(content_type) @compressible_content_types.match?(content_type) end
# File lib/static-rails/file_handler.rb, line 142 def each_candidate_filepath(path_info) return unless (path = clean_path(path_info)) ext = ::File.extname(path) content_type = ::Rack::Mime.mime_type(ext, nil) yield path, content_type || "text/plain" # Tack on .html and /index.html only for paths that don't have # an explicit, resolvable file extension. No need to check # for foo.js.html and foo.js/index.html. unless content_type default_ext = ::ActionController::Base.default_static_extension if ext != default_ext default_content_type = ::Rack::Mime.mime_type(default_ext, "text/plain") yield "#{path}#{default_ext}", default_content_type yield "#{path}/#{@index}#{default_ext}", default_content_type end end nil end
# File lib/static-rails/file_handler.rb, line 133 def each_precompressed_filepath(filepath) @precompressed.each do |content_encoding| precompressed_ext = PRECOMPRESSED.fetch(content_encoding) yield content_encoding, "#{filepath}#{precompressed_ext}" end nil end
# File lib/static-rails/file_handler.rb, line 121 def file_readable?(path) file_stat = File.stat(File.join(@root, path.b)) rescue SystemCallError false else file_stat.file? && file_stat.readable? end
# File lib/static-rails/file_handler.rb, line 89 def try_files(filepath, content_type, accept_encoding:) headers = {"Content-Type" => content_type} if compressible? content_type try_precompressed_files filepath, headers, accept_encoding: accept_encoding elsif file_readable? filepath [filepath, headers] end end
# File lib/static-rails/file_handler.rb, line 99 def try_precompressed_files(filepath, headers, accept_encoding:) each_precompressed_filepath(filepath) do |content_encoding, precompressed_filepath| if file_readable? precompressed_filepath # Identity encoding is default, so we skip Accept-Encoding # negotiation and needn't set Content-Encoding. # # Vary header is expected when we've found other available # encodings that Accept-Encoding ruled out. if content_encoding == "identity" return precompressed_filepath, headers else headers["Vary"] = "Accept-Encoding" if accept_encoding.any? { |enc, _| /\b#{content_encoding}\b/i.match?(enc) } headers["Content-Encoding"] = content_encoding return precompressed_filepath, headers end end end end end