# frozen_string_literal: true
require_relative 'constants'
require_relative 'utils'
module Rack
warn "Rack::Chunked is deprecated and will be removed in Rack 3.1", uplevel: 1
# Middleware that applies chunked transfer encoding to response bodies
# when the response does not include a content-length header.
#
# This supports the trailer response header to allow the use of trailing
# headers in the chunked encoding. However, using this requires you manually
# specify a response body that supports a +trailers+ method. Example:
#
# [200, { 'trailer' => 'expires'}, ["Hello", "World"]]
# # error raised
#
# body = ["Hello", "World"]
# def body.trailers
# { 'expires' => Time.now.to_s }
# end
# [200, { 'trailer' => 'expires'}, body]
# # No exception raised
class Chunked
include Rack::Utils
# A body wrapper that emits chunked responses.
class Body
TERM = "\r\n"
TAIL = "0#{TERM}"
# Store the response body to be chunked.
def initialize(body)
@body = body
end
# For each element yielded by the response body, yield
# the element in chunked encoding.
def each(&block)
term = TERM
@body.each do |chunk|
size = chunk.bytesize
next if size == 0
yield [size.to_s(16), term, chunk.b, term].join
end
yield TAIL
yield_trailers(&block)
yield term
end
# Close the response body if the response body supports it.
def close
@body.close if @body.respond_to?(:close)
end
private
# Do nothing as this class does not support trailer headers.
def yield_trailers
end
end
# A body wrapper that emits chunked responses and also supports
# sending Trailer headers. Note that the response body provided to
# initialize must have a +trailers+ method that returns a hash
# of trailer headers, and the rack response itself should have a
# Trailer header listing the headers that the +trailers+ method
# will return.
class TrailerBody < Body
private
# Yield strings for each trailer header.
def yield_trailers
@body.trailers.each_pair do |k, v|
yield "#{k}: #{v}\r\n"
end
end
end
def initialize(app)
@app = app
end
# Whether the HTTP version supports chunked encoding (HTTP 1.1 does).
def chunkable_version?(ver)
case ver
# pre-HTTP/1.0 (informally "HTTP/0.9") HTTP requests did not have
# a version (nor response headers)
when 'HTTP/1.0', nil, 'HTTP/0.9'
false
else
true
end
end
# If the rack app returns a response that should have a body,
# but does not have content-length or transfer-encoding headers,
# modify the response to use chunked transfer-encoding.
def call(env)
status, headers, body = response = @app.call(env)
if chunkable_version?(env[SERVER_PROTOCOL]) &&
!STATUS_WITH_NO_ENTITY_BODY.key?(status.to_i) &&
!headers[CONTENT_LENGTH] &&
!headers[TRANSFER_ENCODING]
headers[TRANSFER_ENCODING] = 'chunked'
if headers['trailer']
response[2] = TrailerBody.new(body)
else
response[2] = Body.new(body)
end
end
response
end
end
end
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