require 'rack/utils'
module Rack
# Middleware that applies chunked transfer encoding to response bodies
# when the response does not include a Content-Length header.
class Chunked
include Rack::Utils
# A body wrapper that emits chunked responses
class Body
TERM = "\r\n"
TAIL = "0#{TERM}#{TERM}"
include Rack::Utils
def initialize(body)
@body = body
end
def each
term = TERM
@body.each do |chunk|
size = bytesize(chunk)
next if size == 0
chunk = chunk.dup.force_encoding(Encoding::BINARY) if chunk.respond_to?(:force_encoding)
yield [size.to_s(16), term, chunk, term].join
end
yield TAIL
end
def close
@body.close if @body.respond_to?(:close)
end
end
def initialize(app)
@app = app
end
# pre-HTTP/1.0 (informally "HTTP/0.9") HTTP requests did not have
# a version (nor response headers)
def chunkable_version?(ver)
case ver
when "HTTP/1.0", nil, "HTTP/0.9"
false
else
true
end
end
def call(env)
status, headers, body = @app.call(env)
headers = HeaderHash.new(headers)
if ! chunkable_version?(env['HTTP_VERSION']) ||
STATUS_WITH_NO_ENTITY_BODY.include?(status) ||
headers[CONTENT_LENGTH] ||
headers['Transfer-Encoding']
[status, headers, body]
else
headers.delete(CONTENT_LENGTH)
headers['Transfer-Encoding'] = 'chunked'
[status, headers, Body.new(body)]
end
end
end
end
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