Class: Unicorn::HttpResponse

Inherits:
Object
  • Object
show all
Defined in:
lib/unicorn/http_response.rb

Overview

Writes a Rack response to your client using the HTTP/1.1 specification. You use it by simply doing:

status, headers, body = rack_app.call(env)
HttpResponse.write(socket, [ status, headers, body ])

Most header correctness (including Content-Length and Content-Type) is the job of Rack, with the exception of the “Connection: close” and “Date” headers.

A design decision was made to force the client to not pipeline or keepalive requests. HTTP/1.1 pipelining really kills the performance due to how it has to be handled and how unclear the standard is. To fix this the HttpResponse always gives a “Connection: close” header which forces the client to close right away. The bonus for this is that it gives a pretty nice speed boost to most clients since they can close their connection immediately.

Constant Summary collapse

CODES =

Every standard HTTP code mapped to the appropriate message.

Rack::Utils::HTTP_STATUS_CODES.inject({}) { |hash,(code,msg)|
  hash[code] = "#{code} #{msg}"
  hash
}
SKIP =

Rack does not set/require a Date: header. We always override the Connection: and Date: headers no matter what (if anything) our Rack application sent us.

{ 'connection' => true, 'date' => true, 'status' => true }

Class Method Summary collapse

Class Method Details

.write(socket, rack_response, have_header = true) ⇒ Object

writes the rack_response to socket as an HTTP response



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# File 'lib/unicorn/http_response.rb', line 38

def self.write(socket, rack_response, have_header = true)
  status, headers, body = rack_response

  if have_header
    status = CODES[status.to_i] || status
    out = []

    # Don't bother enforcing duplicate supression, it's a Hash most of
    # the time anyways so just hope our app knows what it's doing
    headers.each do |key, value|
      next if SKIP.include?(key.downcase)
      if value =~ /\n/
        # avoiding blank, key-only cookies with /\n+/
        out.concat(value.split(/\n+/).map! { |v| "#{key}: #{v}\r\n" })
      else
        out << "#{key}: #{value}\r\n"
      end
    end

    # Rack should enforce Content-Length or chunked transfer encoding,
    # so don't worry or care about them.
    # Date is required by HTTP/1.1 as long as our clock can be trusted.
    # Some broken clients require a "Status" header so we accomodate them
    socket.write("HTTP/1.1 #{status}\r\n" \
                 "Date: #{Time.now.httpdate}\r\n" \
                 "Status: #{status}\r\n" \
                 "Connection: close\r\n" \
                 "#{out.join('')}\r\n")
  end

  body.each { |chunk| socket.write(chunk) }
  socket.close # flushes and uncorks the socket immediately
  ensure
    body.respond_to?(:close) and body.close
end