Module: Webmachine::Decision::Helpers

Includes:
QuotedString, Streaming
Included in:
FSM
Defined in:
lib/webmachine/decision/helpers.rb

Overview

Methods that assist the Decision Flow.

Constant Summary

Constants included from QuotedString

QuotedString::QS_ANCHORED, QuotedString::QUOTED_STRING

Instance Method Summary collapse

Methods included from QuotedString

#escape_quotes, #quote, #unescape_quotes, #unquote

Instance Method Details

#accept_helper ⇒ Object

Assists in receiving request bodies



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# File 'lib/webmachine/decision/helpers.rb', line 58

def accept_helper
  content_type = MediaType.parse(request.content_type || 'application/octet-stream')
  acceptable = resource.content_types_accepted.find {|ct, _| content_type.match?(ct) }
  if acceptable
    resource.send(acceptable.last)
  else
    415
  end
end

#add_caching_headers ⇒ Object

Adds caching-related headers to the response.



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# File 'lib/webmachine/decision/helpers.rb', line 79

def add_caching_headers
  if etag = resource.generate_etag
    response.headers['ETag'] = ETag.new(etag).to_s
  end
  if expires = resource.expires
    response.headers['Expires'] = expires.httpdate
  end
  if modified = resource.last_modified
    response.headers['Last-Modified'] = modified.httpdate
  end
end

#body_is_fixed_length? ⇒ Boolean

Determines whether the response is of a fixed lenghth, i.e. it is a String or IO with known size.

Returns:

  • (Boolean) 


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# File 'lib/webmachine/decision/helpers.rb', line 124

def body_is_fixed_length?
  response.body.respond_to?(:bytesize) &&
    Fixnum === response.body.bytesize
end

#encode_body ⇒ Object

Encodes the body in the selected charset and encoding.



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# File 'lib/webmachine/decision/helpers.rb', line 27

def encode_body
  body = response.body
  chosen_charset = metadata['Charset']
  chosen_encoding = metadata['Content-Encoding']
  charsetter = resource.charsets_provided && resource.charsets_provided.find {|c,_| c == chosen_charset }.last || :charset_nop
  encoder = resource.encodings_provided[chosen_encoding]
  response.body = case body
                  when String # 1.8 treats Strings as Enumerable
                    resource.send(encoder, resource.send(charsetter, body))
                  when IO, StringIO
                    IOEncoder.new(resource, encoder, charsetter, body)
                  when Fiber
                    FiberEncoder.new(resource, encoder, charsetter, body)
                  when Enumerable
                    EnumerableEncoder.new(resource, encoder, charsetter, body)
                  else
                    if body.respond_to?(:call)
                      CallableEncoder.new(resource, encoder, charsetter, body)
                    else
                      resource.send(encoder, resource.send(charsetter, body))
                    end
                  end
  if body_is_fixed_length?
    set_content_length
  else
    response.headers.delete 'Content-Length'
    response.headers['Transfer-Encoding'] = 'chunked'
  end
end

#encode_body_if_set ⇒ Object

If the response body exists, encode it.

See Also:



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# File 'lib/webmachine/decision/helpers.rb', line 22

def encode_body_if_set
  encode_body if has_response_body?
end

#ensure_content_length ⇒ Object

Ensures that responses have an appropriate Content-Length header



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# File 'lib/webmachine/decision/helpers.rb', line 93

def ensure_content_length
  case
  when response.headers['Transfer-Encoding']
    return
  when [204, 205, 304].include?(response.code)
    response.headers.delete 'Content-Length'
  when has_response_body?
    set_content_length
  else
    response.headers['Content-Length'] = '0'
  end
end

#ensure_date_header ⇒ Object

Ensures that responses have an appropriate Date header



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# File 'lib/webmachine/decision/helpers.rb', line 107

def ensure_date_header
  if (200..499).include?(response.code)
    response.headers['Date'] ||= Time.now.httpdate
  end
end

#has_response_body? ⇒ Boolean

Determines if the response has a body/entity set.

Returns:

  • (Boolean) 


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# File 'lib/webmachine/decision/helpers.rb', line 16

def has_response_body?
  !response.body.nil? && !response.body.empty?
end

#set_content_length ⇒ Object

Sets the Content-Length header on the response



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# File 'lib/webmachine/decision/helpers.rb', line 114

def set_content_length
  if response.body.respond_to?(:bytesize)
    response.headers['Content-Length'] = response.body.bytesize.to_s
  else
    response.headers['Content-Length'] = response.body.length.to_s
  end
end

#variances ⇒ Object

Computes the entries for the ‘Vary’ response header



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# File 'lib/webmachine/decision/helpers.rb', line 69

def variances
  resource.variances.tap do |v|
    v.unshift "Accept-Language" if resource.languages_provided.size > 1
    v.unshift "Accept-Charset" if resource.charsets_provided && resource.charsets_provided.size > 1
    v.unshift "Accept-Encoding" if resource.encodings_provided.size > 1
    v.unshift "Accept" if resource.content_types_provided.size > 1
  end
end