class Rack::Response

Rack::Response provides a convenient interface to create a Rack response.

It allows setting of headers and cookies, and provides useful defaults (an OK response with empty headers and body).

You can use Response#write to iteratively generate your response, but note that this is buffered by Rack::Response until you call finish. finish however can take a block inside which calls to write are synchronous with the Rack response.

Your application’s call should end returning Response#finish.

Constants

CHUNKED
STATUS_WITH_NO_ENTITY_BODY

Attributes

body [RW]

Public Class Methods

[] (status, headers, body) 
# File lib/rack/response.rb, line 24
def self.[](status, headers, body)
  self.new(body, status, headers)
end
new (body = nil, status = 200, headers = {}) { |self| ... }

Initialize the response object with the specified body, status and headers.

If the body is nil, construct an empty response object with internal buffering.

If the body responds to to_str, assume it’s a string-like object and construct a buffered response object containing using that string as the initial contents of the buffer.

Otherwise it is expected body conforms to the normal requirements of a Rack response body, typically implementing one of each (enumerable body) or call (streaming body).

The status defaults to 200 which is the “OK” HTTP status code. You can provide any other valid status code.

The headers must be a Hash of key-value header pairs which conform to the Rack specification for response headers. The key must be a String instance and the value can be either a String or Array instance.

# File lib/rack/response.rb, line 54
def initialize(body = nil, status = 200, headers = {})
  @status = status.to_i

  unless headers.is_a?(Hash)
    raise ArgumentError, "Headers must be a Hash!"
  end

  @headers = Headers.new
  # Convert headers input to a plain hash with lowercase keys.
  headers.each do |k, v|
    @headers[k] = v
  end

  @writer = self.method(:append)

  @block = nil

  # Keep track of whether we have expanded the user supplied body.
  if body.nil?
    @body = []
    @buffered = true
    # Body is unspecified - it may be a buffered response, or it may be a HEAD response.
    @length = nil
  elsif body.respond_to?(:to_str)
    @body = [body]
    @buffered = true
    @length = body.to_str.bytesize
  else
    @body = body
    @buffered = nil # undetermined as of yet.
    @length = nil
  end

  yield self if block_given?
end

Public Instance Methods

chunked? () 
# File lib/rack/response.rb, line 95
def chunked?
  CHUNKED == get_header(TRANSFER_ENCODING)
end
close () 
# File lib/rack/response.rb, line 152
def close
  @body.close if @body.respond_to?(:close)
end
delete_header (key) 
# File lib/rack/response.rb, line 172
def delete_header(key)
  raise ArgumentError unless key.is_a?(String)
  @headers.delete key
end
each (&callback) 
# File lib/rack/response.rb, line 130
def each(&callback)
  @body.each(&callback)
  @buffered = true

  if @block
    @writer = callback
    @block.call(self)
  end
end
empty? () 
# File lib/rack/response.rb, line 156
def empty?
  @block == nil && @body.empty?
end
finish (&block)

Generate a response array consistent with the requirements of the SPEC. @return [Array] a 3-tuple suitable of ‘[status, headers, body]` which is suitable to be returned from the middleware `#call(env)` method.

# File lib/rack/response.rb, line 107
def finish(&block)
  if no_entity_body?
    delete_header CONTENT_TYPE
    delete_header CONTENT_LENGTH
    close
    return [@status, @headers, []]
  else
    if block_given?
      # We don't add the content-length here as the user has provided a block that can #write additional chunks to the body.
      @block = block
      return [@status, @headers, self]
    else
      # If we know the length of the body, set the content-length header... except if we are chunked? which is a legacy special case where the body might already be encoded and thus the actual encoded body length and the content-length are likely to be different.
      if @length && !chunked?
        @headers[CONTENT_LENGTH] = @length.to_s
      end
      return [@status, @headers, @body]
    end
  end
end
Also aliased as: to_a
get_header (key) 
# File lib/rack/response.rb, line 164
def get_header(key)
  raise ArgumentError unless key.is_a?(String)
  @headers[key]
end
Also aliased as: []
has_header? (key) 
# File lib/rack/response.rb, line 160
def has_header?(key)
  raise ArgumentError unless key.is_a?(String)
  @headers.key?(key)
end
no_entity_body? () 
# File lib/rack/response.rb, line 99
def no_entity_body?
  # The response body is an enumerable body and it is not allowed to have an entity body.
  @body.respond_to?(:each) && STATUS_WITH_NO_ENTITY_BODY[@status]
end
redirect (target, status = 302) 
# File lib/rack/response.rb, line 90
def redirect(target, status = 302)
  self.status = status
  self.location = target
end
set_header (key, value) 
# File lib/rack/response.rb, line 168
def set_header(key, value)
  raise ArgumentError unless key.is_a?(String)
  @headers[key] = value
end
Also aliased as: []=
write (chunk)

Append a chunk to the response body.

Converts the response into a buffered response if it wasn’t already.

NOTE: Do not mix write and direct body access!

# File lib/rack/response.rb, line 146
def write(chunk)
  buffered_body!

  @writer.call(chunk.to_s)
end