1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
| | require "zlib"
require "stringio"
require "time" # for Time.httpdate
require 'rack/utils'
module Rack
# This middleware enables compression of http responses.
#
# Currently supported compression algorithms:
#
# * gzip
# * deflate
# * identity (no transformation)
#
# The middleware automatically detects when compression is supported
# and allowed. For example no transformation is made when a cache
# directive of 'no-transform' is present, or when the response status
# code is one that doesn't allow an entity body.
class Deflater
##
# Creates Rack::Deflater middleware.
#
# [app] rack app instance
# [options] hash of deflater options, i.e.
# 'if' - a lambda enabling / disabling deflation based on returned boolean value
# e.g use Rack::Deflater, :if => lambda { |env, status, headers, body| body.length > 512 }
# 'include' - a list of content types that should be compressed
def initialize(app, options = {})
@app = app
@condition = options[:if]
@compressible_types = options[:include]
end
def call(env)
status, headers, body = @app.call(env)
headers = Utils::HeaderHash.new(headers)
unless should_deflate?(env, status, headers, body)
return [status, headers, body]
end
request = Request.new(env)
encoding = Utils.select_best_encoding(%w(gzip deflate identity),
request.accept_encoding)
# Set the Vary HTTP header.
vary = headers["Vary"].to_s.split(",").map { |v| v.strip }
unless vary.include?("*") || vary.include?("Accept-Encoding")
headers["Vary"] = vary.push("Accept-Encoding").join(",")
end
case encoding
when "gzip"
headers['Content-Encoding'] = "gzip"
headers.delete(CONTENT_LENGTH)
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
message = "An acceptable encoding for the requested resource #{request.fullpath} could not be found."
bp = Rack::BodyProxy.new([message]) { body.close if body.respond_to?(:close) }
[406, {CONTENT_TYPE => "text/plain", CONTENT_LENGTH => message.length.to_s}, bp]
end
end
class GzipStream
def initialize(body, mtime)
@body = body
@mtime = mtime
@closed = false
end
def each(&block)
@writer = block
gzip =::Zlib::GzipWriter.new(self)
gzip.mtime = @mtime
@body.each { |part|
gzip.write(part)
gzip.flush
}
ensure
gzip.close
@writer = nil
end
def write(data)
@writer.call(data)
end
def close
return if @closed
@closed = true
@body.close if @body.respond_to?(:close)
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 deflator.finish
nil
ensure
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)
# Skip compressing empty entity body responses and responses with
# no-transform set.
if Utils::STATUS_WITH_NO_ENTITY_BODY.include?(status) ||
headers[CACHE_CONTROL].to_s =~ /\bno-transform\b/ ||
(headers['Content-Encoding'] && headers['Content-Encoding'] !~ /\bidentity\b/)
return false
end
# Skip if @compressible_types are given and does not include request's content type
return false if @compressible_types && !(headers.has_key?('Content-Type') && @compressible_types.include?(headers['Content-Type'][/[^;]*/]))
# Skip if @condition lambda is given and evaluates to false
return false if @condition && !@condition.call(env, status, headers, body)
true
end
end
end
|