From 6b5dcfcf93cc34f2bfd1f435ae29548018315f2c Mon Sep 17 00:00:00 2001
From: Jonathan Baudanza <jon@jonb.org>
Date: Tue, 26 Feb 2013 22:15:50 -0800
Subject: [PATCH] Added GzFile for serving gzipped static files

---
 lib/rack.rb                         |   1 +
 lib/rack/gz_file.rb                 |  41 ++++++++++++++++++++++++++
 test/cgi/assets/compress_me.html    |   1 +
 test/cgi/assets/compress_me.html.gz | Bin 0 -> 49 bytes
 test/spec_gz_file.rb                |  43 ++++++++++++++++++++++++++++
 5 files changed, 86 insertions(+)
 create mode 100644 lib/rack/gz_file.rb
 create mode 100644 test/cgi/assets/compress_me.html
 create mode 100644 test/cgi/assets/compress_me.html.gz
 create mode 100644 test/spec_gz_file.rb

diff --git a/lib/rack.rb b/lib/rack.rb
index 57119df3a..a05985c66 100644
--- a/lib/rack.rb
+++ b/lib/rack.rb
@@ -34,6 +34,7 @@ def self.release
   autoload :ContentType, "rack/content_type"
   autoload :ETag, "rack/etag"
   autoload :File, "rack/file"
+  autoload :GzFile, "rack/gz_file"
   autoload :Deflater, "rack/deflater"
   autoload :Directory, "rack/directory"
   autoload :ForwardRequest, "rack/recursive"
diff --git a/lib/rack/gz_file.rb b/lib/rack/gz_file.rb
new file mode 100644
index 000000000..c97d3f3cc
--- /dev/null
+++ b/lib/rack/gz_file.rb
@@ -0,0 +1,41 @@
+module Rack
+  # Rack::GzFile behaves exactly the same as Rack::File, except that it will
+  # also serve up a gzip encoding of a file, if one is available on the
+  # filesystem.
+  #
+  # For each request, Rack::GzFile first checks the filesystem for a file with a
+  # .gz extension. If one is found, the appropriate encoding headers are added
+  # to the response and the gzip file is served.
+  #
+  # If no .gz file is found, Rack::GzFile will behave exactly like Rack::File.
+  class GzFile
+    def initialize(root, headers={}, default_mime = 'text/plain')
+      @file_server = Rack::File.new(root, headers, default_mime)
+      @default_mime = default_mime
+    end
+
+    def call(env)
+      path_info = env['PATH_INFO']
+
+      status, headers, body = @file_server.call(
+        env.merge('PATH_INFO' => path_info + '.gz')
+      )
+
+      gzip_available = status != 404
+
+      if !gzip_available || env['HTTP_ACCEPT_ENCODING'] !~ /\bgzip\b/
+        status, headers, body = @file_server.call(env)
+      else
+        headers['Content-Type'] = Mime.mime_type(::File.extname(path_info), 
+                                                 @default_mime)
+        headers['Content-Encoding'] = 'gzip'
+      end
+
+      if gzip_available
+        headers['Vary'] = 'Accept-Encoding'
+      end
+
+      [status, headers, body]
+    end
+  end
+end
diff --git a/test/cgi/assets/compress_me.html b/test/cgi/assets/compress_me.html
new file mode 100644
index 000000000..3f0ce957d
--- /dev/null
+++ b/test/cgi/assets/compress_me.html
@@ -0,0 +1 @@
+Hello, Rack!
\ No newline at end of file
diff --git a/test/cgi/assets/compress_me.html.gz b/test/cgi/assets/compress_me.html.gz
new file mode 100644
index 0000000000000000000000000000000000000000..8c2c944aec5d25d44e3e23a5ed645a01e2d9c0e2
GIT binary patch
literal 49
zcmb2|=HN)5r5nh=oSdIqP?TC+9G{!2mr;_N!|>VT?8%eY13A2W&V{isNKGk^;$dK5
F006B&5YPYs

literal 0
HcmV?d00001

diff --git a/test/spec_gz_file.rb b/test/spec_gz_file.rb
new file mode 100644
index 000000000..7332e56c4
--- /dev/null
+++ b/test/spec_gz_file.rb
@@ -0,0 +1,43 @@
+require 'rack/gz_file'
+require 'rack/lint'
+require 'rack/mock'
+require 'zlib'
+
+describe Rack::GzFile do
+  DOCROOT = File.expand_path(File.dirname(__FILE__)) unless defined? DOCROOT
+
+  def request
+    Rack::MockRequest.new(Rack::Lint.new(Rack::GzFile.new(DOCROOT)))
+  end
+
+  should "serve an uncompressed file when gzip is not supported by the server" do
+    res = request.get('/cgi/assets/index.html')
+    res.body.should.equal "### TestFile ###\n"
+    res.headers.should.not.include 'Vary'
+    res.headers.should.not.include('Content-Encoding')
+    res.headers['Content-Length'].should.equal(
+        File.size(DOCROOT + '/cgi/assets/index.html').to_s)
+  end
+
+  should "serve an uncompressed file when gzip is not supported by the client" do
+    res = request.get('/cgi/assets/compress_me.html')
+    res.body.should.equal 'Hello, Rack!'
+    res.headers['Vary'].should.equal 'Accept-Encoding'
+    res.headers.should.not.include('Content-Encoding')
+    res.headers['Content-Length'].should.equal(
+        File.size(DOCROOT + '/cgi/assets/compress_me.html').to_s)
+  end
+
+  should "serve a compressed file" do
+    res = request.get('/cgi/assets/compress_me.html', 
+        'HTTP_ACCEPT_ENCODING' => 'gzip')
+
+    gz = Zlib::GzipReader.new(StringIO.new(res.body))
+    gz.read.should.equal "Hello, Rack!"
+    res.headers['Vary'].should.equal 'Accept-Encoding'
+    res.headers['Content-Encoding'].should.equal 'gzip'
+    res.headers['Content-Type'].should.equal 'text/html'
+    res.headers['Content-Length'].should.equal(
+        File.size(DOCROOT + '/cgi/assets/compress_me.html.gz').to_s)
+  end
+end
\ No newline at end of file