Class: Pitchfork::Chunked

Inherits:
Object
  • Object
show all
Includes:
Rack::Utils
Defined in:
lib/pitchfork/chunked.rb

Overview

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

Defined Under Namespace

Classes: Body, TrailerBody

Constant Summary collapse

STATUS_WITH_NO_ENTITY_BODY = 
Hash[((100..199).to_a << 204 << 304).product([true]

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Chunked

Returns a new instance of Chunked.



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# File 'lib/pitchfork/chunked.rb', line 85

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object

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.



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# File 'lib/pitchfork/chunked.rb', line 104

def call(env)
  status, headers, body = response = @app.call(env)

  if !env.key?('rack.hijack_io') && # full highjack
     !headers['rack.hijack'] && # partial hijack
     body.respond_to?(:each) && # body must be enumerable (i.e. non-streaming)
      chunkable_version?(env[Rack::SERVER_PROTOCOL]) &&
     !STATUS_WITH_NO_ENTITY_BODY.key?(status.to_i) &&
     !headers[Rack::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

#chunkable_version?(ver) ⇒ Boolean

Whether the HTTP version supports chunked encoding (HTTP 1.1 does).

Returns:

  • (Boolean) 


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# File 'lib/pitchfork/chunked.rb', line 90

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