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From: Eric Wong <e@80x24.org>
To: rack-devel@googlegroups.com
Subject: [PATCH] deflater: remove "deflate" encoding support
Date: Wed, 27 Jul 2016 02:10:48 +0000	[thread overview]
Message-ID: <20160727021048.GA27519@starla> (raw)

This will improve cache hit rates and reduce caching overhead at
small expense of increased header overhead for some user agents.
For reference, Varnish cache supports only gzip as well:

	https://www.varnish-cache.org/docs/4.1/phk/gzip.html

In the past, "deflate" encoding was more likely to trigger
user-agent bugs, as noted in the comments removed with this
change as well as the Varnish documentation referenced above.
---
  The following changes since commit 25a549883b85fb33970b4a1530a365c0c9e51f95:

    bumping to 2.0.1 to work around Rack (2016-06-30 10:33:09 -0700)

  are available in the git repository at:

    git://80x24.org/rack.git no-deflate

  for you to fetch changes up to d6380043a8953dca63743c947c8027f465d29a5d:

    deflater: remove "deflate" encoding support (2016-07-26 23:14:55 +0000)

  ----------------------------------------------------------------
  Eric Wong (1):
        deflater: remove "deflate" encoding support

 lib/rack/deflater.rb  | 37 +------------------------------------
 test/spec_deflater.rb | 38 ++++++++++++++++++++++++--------------
 2 files changed, 25 insertions(+), 50 deletions(-)

diff --git a/lib/rack/deflater.rb b/lib/rack/deflater.rb
index 62a1124..79e39f5 100644
--- a/lib/rack/deflater.rb
+++ b/lib/rack/deflater.rb
@@ -8,7 +8,6 @@ module Rack
   # Currently supported compression algorithms:
   #
   #   * gzip
-  #   * deflate
   #   * identity (no transformation)
   #
   # The middleware automatically detects when compression is supported
@@ -41,7 +40,7 @@ module Rack
 
       request = Request.new(env)
 
-      encoding = Utils.select_best_encoding(%w(gzip deflate identity),
+      encoding = Utils.select_best_encoding(%w(gzip identity),
                                             request.accept_encoding)
 
       # Set the Vary HTTP header.
@@ -57,10 +56,6 @@ module Rack
         mtime = headers.key?("Last-Modified") ?
           Time.httpdate(headers["Last-Modified"]) : Time.now
         [status, headers, GzipStream.new(body, mtime)]
-      when "deflate"
-        headers['Content-Encoding'] = "deflate"
-        headers.delete(CONTENT_LENGTH)
-        [status, headers, DeflateStream.new(body)]
       when "identity"
         [status, headers, body]
       when nil
@@ -101,36 +96,6 @@ module Rack
       end
     end
 
-    class DeflateStream
-      DEFLATE_ARGS = [
-        Zlib::DEFAULT_COMPRESSION,
-        # drop the zlib header which causes both Safari and IE to choke
-        -Zlib::MAX_WBITS,
-        Zlib::DEF_MEM_LEVEL,
-        Zlib::DEFAULT_STRATEGY
-      ]
-
-      def initialize(body)
-        @body = body
-        @closed = false
-      end
-
-      def each
-        deflator = ::Zlib::Deflate.new(*DEFLATE_ARGS)
-        @body.each { |part| yield deflator.deflate(part, Zlib::SYNC_FLUSH) }
-        yield fin = deflator.finish
-      ensure
-        deflator.finish unless fin
-        deflator.close
-      end
-
-      def close
-        return if @closed
-        @closed = true
-        @body.close if @body.respond_to?(:close)
-      end
-    end
-
     private
 
     def should_deflate?(env, status, headers, body)
diff --git a/test/spec_deflater.rb b/test/spec_deflater.rb
index ba7ec5d..0f27c85 100644
--- a/test/spec_deflater.rb
+++ b/test/spec_deflater.rb
@@ -81,13 +81,22 @@ describe Rack::Deflater do
     yield(status, headers, body) if block_given?
   end
 
+  # automatic gzip detection (streamable)
+  def auto_inflater
+    Zlib::Inflate.new(32 + Zlib::MAX_WBITS)
+  end
+
+  def deflate_or_gzip
+    {'deflate, gzip' => 'gzip'}
+  end
+
   it 'be able to deflate bodies that respond to each' do
     app_body = Object.new
     class << app_body; def each; yield('foo'); yield('bar'); end; end
 
-    verify(200, 'foobar', 'deflate', { 'app_body' => app_body }) do |status, headers, body|
+    verify(200, 'foobar', deflate_or_gzip, { 'app_body' => app_body }) do |status, headers, body|
       headers.must_equal({
-        'Content-Encoding' => 'deflate',
+        'Content-Encoding' => 'gzip',
         'Vary' => 'Accept-Encoding',
         'Content-Type' => 'text/plain'
       })
@@ -98,15 +107,15 @@ describe Rack::Deflater do
     app_body = Object.new
     class << app_body; def each; yield('foo'); yield('bar'); end; end
 
-    verify(200, app_body, 'deflate', { 'skip_body_verify' => true }) do |status, headers, body|
+    verify(200, app_body, deflate_or_gzip, { 'skip_body_verify' => true }) do |status, headers, body|
       headers.must_equal({
-        'Content-Encoding' => 'deflate',
+        'Content-Encoding' => 'gzip',
         'Vary' => 'Accept-Encoding',
         'Content-Type' => 'text/plain'
       })
 
       buf = []
-      inflater = Zlib::Inflate.new(-Zlib::MAX_WBITS)
+      inflater = auto_inflater
       body.each { |part| buf << inflater.inflate(part) }
       buf << inflater.finish
 
@@ -118,32 +127,33 @@ describe Rack::Deflater do
     app_body = Object.new
     class << app_body; def each; yield('foo'); yield('bar'); end; end
     opts = { 'skip_body_verify' => true }
-    verify(200, app_body, 'deflate', opts) do |status, headers, body|
+    verify(200, app_body, 'gzip', opts) do |status, headers, body|
       headers.must_equal({
-        'Content-Encoding' => 'deflate',
+        'Content-Encoding' => 'gzip',
         'Vary' => 'Accept-Encoding',
         'Content-Type' => 'text/plain'
       })
 
       buf = []
-      inflater = Zlib::Inflate.new(-Zlib::MAX_WBITS)
+      inflater = auto_inflater
       FakeDisconnect = Class.new(RuntimeError)
       assert_raises(FakeDisconnect, "not Zlib::DataError not raised") do
         body.each do |part|
-          buf << inflater.inflate(part)
+          tmp = inflater.inflate(part)
+          buf << tmp if tmp.bytesize > 0
           raise FakeDisconnect
         end
       end
-      assert_raises(Zlib::BufError) { inflater.finish }
+      inflater.finish
       buf.must_equal(%w(foo))
     end
   end
 
   # TODO: This is really just a special case of the above...
   it 'be able to deflate String bodies' do
-    verify(200, 'Hello world!', 'deflate') do |status, headers, body|
+    verify(200, 'Hello world!', deflate_or_gzip) do |status, headers, body|
       headers.must_equal({
-        'Content-Encoding' => 'deflate',
+        'Content-Encoding' => 'gzip',
         'Vary' => 'Accept-Encoding',
         'Content-Type' => 'text/plain'
       })
@@ -280,7 +290,7 @@ describe Rack::Deflater do
         'Content-Encoding' => 'identity'
       }
     }
-    verify(200, 'Hello World!', 'deflate', options)
+    verify(200, 'Hello World!', deflate_or_gzip, options)
   end
 
   it "deflate if content-type matches :include" do
@@ -334,7 +344,7 @@ describe Rack::Deflater do
         :if => lambda { |env, status, headers, body| true }
       }
     }
-    verify(200, 'Hello World!', 'deflate', options)
+    verify(200, 'Hello World!', deflate_or_gzip, options)
   end
 
   it "not deflate if :if lambda evaluates to false" do
-- 
EW

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             reply	other threads:[~2016-07-27  2:10 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-27  2:10 Eric Wong [this message]
2016-07-27  2:44 ` James Tucker
2016-07-27  6:40   ` Eric Wong
2016-07-27  8:46     ` Eric Wong
2016-08-23 19:40       ` James Tucker
2019-04-21 19:51   ` Vy Nguyen

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