Module: Webmachine::Decision::Flow

Includes:
Conneg, Translation
Included in:
FSM
Defined in:
lib/webmachine/decision/flow.rb

Overview

This module encapsulates all of the decisions in Webmachine’s flow-chart. These invoke Resource::Callbacks methods to determine the appropriate response code, headers, and body for the response.

This module is included into FSM, which drives the processing of the chart.

See Also:

Constant Summary collapse

VERSION =

Version of the flow diagram

3
START =

The first state in flow diagram

:b13

Constants included from Conneg

Conneg::HAS_ENCODING

Instance Method Summary collapse

Methods included from Translation

#t

Methods included from Conneg

#choose_charset, #choose_encoding, #choose_language, #choose_media_type, #do_choose, #language_match

Instance Method Details

#b10 ⇒ Object

Method allowed?



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# File 'lib/webmachine/decision/flow.rb', line 59

def b10
  if resource.allowed_methods.include?(request.method)
    :b9
  else
    response.headers["Allow"] = resource.allowed_methods.join(", ")
    405
  end
end

#b11 ⇒ Object

URI too long?



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# File 'lib/webmachine/decision/flow.rb', line 54

def b11
  decision_test(resource.uri_too_long?(request.uri), 414, :b10)
end

#b12 ⇒ Object

Known method?



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# File 'lib/webmachine/decision/flow.rb', line 49

def b12
  decision_test(resource.known_methods.include?(request.method), :b11, 501)
end

#b13 ⇒ Object

Service available?



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# File 'lib/webmachine/decision/flow.rb', line 44

def b13
  decision_test(resource.service_available?, :b12, 503)
end

#b3 ⇒ Object

OPTIONS?



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# File 'lib/webmachine/decision/flow.rb', line 135

def b3
  if request.options?
    response.headers.merge!(resource.options)
    200
  else
    :c3
  end
end

#b4 ⇒ Object

Req Entity Too Large?



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# File 'lib/webmachine/decision/flow.rb', line 130

def b4
  decision_test(resource.valid_entity_length?(request.content_length), :b3, 413)
end

#b5 ⇒ Object

Known Content-Type?



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# File 'lib/webmachine/decision/flow.rb', line 125

def b5
  decision_test(resource.known_content_type?(request.content_type), :b4, 415)
end

#b6 ⇒ Object

Okay Content-* Headers?



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# File 'lib/webmachine/decision/flow.rb', line 120

def b6
  decision_test(resource.valid_content_headers?(request.headers.grep(/content-/)), :b5,  501)
end

#b7 ⇒ Object

Forbidden?



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# File 'lib/webmachine/decision/flow.rb', line 115

def b7
  decision_test(resource.forbidden?, 403, :b6)
end

#b8 ⇒ Object

Authorized?



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# File 'lib/webmachine/decision/flow.rb', line 99

def b8
  result = resource.is_authorized?(request.authorization)
  case result
  when true
    :b7
  when Fixnum
    result
  when String
    response.headers['WWW-Authenticate'] = result
    401
  else
    401
  end
end

#b9 ⇒ Object

Content-MD5 present?



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

def b9
  request.content_md5 ? :b9a : :b9b
end

#b9a ⇒ Object

Content-MD5 valid?



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# File 'lib/webmachine/decision/flow.rb', line 74

def b9a
  case valid = resource.validate_content_checksum
  when Fixnum
    valid
  when true
    :b9b
  when false
    response.body = "Content-MD5 header does not match request body."
    400
  else # not_validated
    if request.content_md5 == Digest::MD5.hexdigest(request.body)
      :b9b
    else
      response.body = "Content-MD5 header does not match request body."
      400
    end
  end
end

#b9b ⇒ Object

Malformed?



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# File 'lib/webmachine/decision/flow.rb', line 94

def b9b
  decision_test(resource.malformed_request?, 400, :b8)
end

#c3 ⇒ Object

Accept exists?



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# File 'lib/webmachine/decision/flow.rb', line 145

def c3
  if !request.accept
    metadata['Content-Type'] = MediaType.parse(resource.content_types_provided.first.first)
    :d4
  else
    :c4
  end
end

#c4 ⇒ Object

Acceptable media type available?



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# File 'lib/webmachine/decision/flow.rb', line 155

def c4
  types = resource.content_types_provided.map {|pair| pair.first }
  chosen_type = choose_media_type(types, request.accept)
  if !chosen_type
    406
  else
    metadata['Content-Type'] = chosen_type
    :d4
  end
end

#d4 ⇒ Object

Accept-Language exists?



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# File 'lib/webmachine/decision/flow.rb', line 167

def d4
  if !request.accept_language
    if language = choose_language(resource.languages_provided, "*")
      resource.language_chosen(language)
      :e5
    else
      406
    end
  else
    :d5
  end
end

#d5 ⇒ Object

Acceptable language available?



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# File 'lib/webmachine/decision/flow.rb', line 181

def d5
  if language = choose_language(resource.languages_provided, request.accept_language)
    resource.language_chosen(language)
    :e5
  else
    406
  end
end

#decision_test(test, iftrue, iffalse) ⇒ Object

Handles standard decisions where halting is allowed



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# File 'lib/webmachine/decision/flow.rb', line 32

def decision_test(test, iftrue, iffalse)
  case test
  when Fixnum # Allows callbacks to "halt" with a given response code
    test
  when Falsey
    iffalse
  else
    iftrue
  end
end

#e5 ⇒ Object

Accept-Charset exists?



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# File 'lib/webmachine/decision/flow.rb', line 191

def e5
  if !request.accept_charset
    choose_charset(resource.charsets_provided, "*") ? :f6 : 406
  else
    :e6
  end
end

#e6 ⇒ Object

Acceptable Charset available?



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# File 'lib/webmachine/decision/flow.rb', line 200

def e6
  choose_charset(resource.charsets_provided, request.accept_charset) ? :f6 : 406
end

#f6 ⇒ Object

Accept-Encoding exists? (also, set content-type header here, now that charset is chosen)



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# File 'lib/webmachine/decision/flow.rb', line 206

def f6
  chosen_type = metadata['Content-Type']
  if chosen_charset = metadata['Charset']
    chosen_type.params['charset'] = chosen_charset
  end
  response.headers['Content-Type'] = chosen_type.to_s
  if !request.accept_encoding
    choose_encoding(resource.encodings_provided, "identity;q=1.0,*;q=0.5") ? :g7 : 406
  else
    :f7
  end
end

#f7 ⇒ Object

Acceptable encoding available?



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# File 'lib/webmachine/decision/flow.rb', line 220

def f7
  choose_encoding(resource.encodings_provided, request.accept_encoding) ? :g7 : 406
end

#g11 ⇒ Object

ETag in If-Match



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# File 'lib/webmachine/decision/flow.rb', line 242

def g11
  request_etags = request.if_match.split(/\s*,\s*/).map {|etag| ETag.new(etag) }
  request_etags.include?(ETag.new(resource.generate_etag)) ? :h10 : 412
end

#g7 ⇒ Object

Resource exists?



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# File 'lib/webmachine/decision/flow.rb', line 225

def g7
  # This is the first place after all conneg, so set Vary here
  response.headers['Vary'] =  variances.join(", ") if variances.any?
  decision_test(resource.resource_exists?, :g8, :h7)
end

#g8 ⇒ Object

If-Match exists?



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# File 'lib/webmachine/decision/flow.rb', line 232

def g8
  request.if_match ? :g9 : :h10
end

#g9 ⇒ Object

If-Match: * exists?



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# File 'lib/webmachine/decision/flow.rb', line 237

def g9
  quote(request.if_match) == '"*"' ? :h10 : :g11
end

#h10 ⇒ Object

If-Unmodified-Since exists?



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# File 'lib/webmachine/decision/flow.rb', line 253

def h10
  request.if_unmodified_since ? :h11 : :i12
end

#h11 ⇒ Object

If-Unmodified-Since is valid date?



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# File 'lib/webmachine/decision/flow.rb', line 258

def h11
  date = Time.httpdate(request.if_unmodified_since)
  metadata['If-Unmodified-Since'] = date
rescue ArgumentError
  :i12
else
  :h12
end

#h12 ⇒ Object

Last-Modified > I-UM-S?



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# File 'lib/webmachine/decision/flow.rb', line 268

def h12
  resource.last_modified > metadata['If-Unmodified-Since'] ? 412 : :i12
end

#h7 ⇒ Object

If-Match exists?



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# File 'lib/webmachine/decision/flow.rb', line 248

def h7
  (request.if_match && unquote(request.if_match) == '*') ? 412 : :i7
end

#i12 ⇒ Object

If-none-match exists?



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# File 'lib/webmachine/decision/flow.rb', line 291

def i12
  request.if_none_match ? :i13 : :l13
end

#i13 ⇒ Object

If-none-match: * exists?



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# File 'lib/webmachine/decision/flow.rb', line 296

def i13
  quote(request.if_none_match) == '"*"' ? :j18 : :k13
end

#i4 ⇒ Object

Moved permanently? (apply PUT to different URI)



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# File 'lib/webmachine/decision/flow.rb', line 273

def i4
  case uri = resource.moved_permanently?
  when String, URI
    response.headers["Location"] = uri.to_s
    301
  when Fixnum
    uri
  else
    :p3
  end
end

#i7 ⇒ Object

PUT?



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# File 'lib/webmachine/decision/flow.rb', line 286

def i7
  request.put? ? :i4 : :k7
end

#j18 ⇒ Object

GET or HEAD?



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# File 'lib/webmachine/decision/flow.rb', line 301

def j18
  (request.get? || request.head?) ? 304 : 412
end

#k13 ⇒ Object

Etag in if-none-match?



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# File 'lib/webmachine/decision/flow.rb', line 324

def k13
  request_etags = request.if_none_match.split(/\s*,\s*/).map {|etag| ETag.new(etag) }
  request_etags.include?(ETag.new(resource.generate_etag)) ? :j18 : :l13
end

#k5 ⇒ Object

Moved permanently?



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# File 'lib/webmachine/decision/flow.rb', line 306

def k5
  case uri = resource.moved_permanently?
  when String, URI
    response.headers["Location"] = uri.to_s
    301
  when Fixnum
    uri
  else
    :l5
  end
end

#k7 ⇒ Object

Previously existed?



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# File 'lib/webmachine/decision/flow.rb', line 319

def k7
  decision_test(resource.previously_existed?, :k5, :l7)
end

#l13 ⇒ Object

If-Modified-Since exists?



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# File 'lib/webmachine/decision/flow.rb', line 348

def l13
  request.if_modified_since ? :l14 : :m16
end

#l14 ⇒ Object

IMS is valid date?



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# File 'lib/webmachine/decision/flow.rb', line 353

def l14
  date = Time.httpdate(request.if_modified_since)
  metadata['If-Modified-Since'] = date
rescue ArgumentError
  :m16
else
  :l15
end

#l15 ⇒ Object

IMS > Now?



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# File 'lib/webmachine/decision/flow.rb', line 363

def l15
  metadata['If-Modified-Since'] > Time.now ? :m16 : :l17
end

#l17 ⇒ Object

Last-Modified > IMS?



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# File 'lib/webmachine/decision/flow.rb', line 368

def l17
  resource.last_modified.nil? || resource.last_modified > metadata['If-Modified-Since'] ? :m16 : 304
end

#l5 ⇒ Object

Moved temporarily?



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# File 'lib/webmachine/decision/flow.rb', line 330

def l5
  case uri = resource.moved_temporarily?
  when String, URI
    response.headers["Location"] = uri.to_s
    307
  when Fixnum
    uri
  else
    :m5
  end
end

#l7 ⇒ Object

POST?



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# File 'lib/webmachine/decision/flow.rb', line 343

def l7
  request.post? ? :m7 : 404
end

#m16 ⇒ Object

DELETE?



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# File 'lib/webmachine/decision/flow.rb', line 383

def m16
  request.delete? ? :m20 : :n16
end

#m20 ⇒ Object

DELETE enacted immediately? (Also where DELETE is forced.)



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# File 'lib/webmachine/decision/flow.rb', line 388

def m20
  decision_test(resource.delete_resource, :m20b, 500)
end

#m20b ⇒ Object

Did the DELETE complete?



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# File 'lib/webmachine/decision/flow.rb', line 393

def m20b
  decision_test(resource.delete_completed?, :o20, 202)
end

#m5 ⇒ Object

POST?



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# File 'lib/webmachine/decision/flow.rb', line 373

def m5
  request.post? ? :n5 : 410
end

#m7 ⇒ Object

Server allows POST to missing resource?



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# File 'lib/webmachine/decision/flow.rb', line 378

def m7
  decision_test(resource.allow_missing_post?, :n11, 404)
end

#n11 ⇒ Object

Redirect?



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# File 'lib/webmachine/decision/flow.rb', line 403

def n11
  # Stage1
  if resource.post_is_create?
    case uri = resource.create_path
    when nil
      raise InvalidResource, t('create_path_nil', :class => resource.class)
    when URI, String
      base_uri = resource.base_uri || request.base_uri
      new_uri = URI.join(base_uri.to_s, uri)
      request.disp_path = new_uri.path
      response.headers['Location'] = new_uri.to_s
      result = accept_helper
      return result if Fixnum === result
    end
  else
    case result = resource.process_post
    when true
      encode_body_if_set
    when Fixnum
      return result
    else
      raise InvalidResource, t('process_post_invalid', :result => result.inspect)
    end
  end
  if response.is_redirect?
    if response.headers['Location']
      303
    else
      raise InvalidResource, t('do_redirect')
    end
  else
    :p11
  end
end

#n16 ⇒ Object

POST?



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# File 'lib/webmachine/decision/flow.rb', line 439

def n16
  request.post? ? :n11 : :o16
end

#n5 ⇒ Object

Server allows POST to missing resource?



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# File 'lib/webmachine/decision/flow.rb', line 398

def n5
  decision_test(resource.allow_missing_post?, :n11, 410)
end

#o14 ⇒ Object

Conflict?



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# File 'lib/webmachine/decision/flow.rb', line 444

def o14
  if resource.is_conflict?
    409
  else
    res = accept_helper
    (Fixnum === res) ? res : :p11
  end
end

#o16 ⇒ Object

PUT?



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# File 'lib/webmachine/decision/flow.rb', line 454

def o16
  request.put? ? :o14 : :o18
end

#o18 ⇒ Object

Multiple representations? Also where body generation for GET and HEAD is done.



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# File 'lib/webmachine/decision/flow.rb', line 460

def o18
  if request.get? || request.head?
    add_caching_headers
    content_type = metadata['Content-Type']
    handler = resource.content_types_provided.find {|ct, _| content_type.type_matches?(MediaType.parse(ct)) }.last
    result = resource.send(handler)
    if Fixnum === result
      result
    else
      response.body = result
      encode_body
      :o18b
    end
  else
    :o18b
  end
end

#o18b ⇒ Object

Multiple choices?



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# File 'lib/webmachine/decision/flow.rb', line 479

def o18b
  decision_test(resource.multiple_choices?, 300, 200)
end

#o20 ⇒ Object

Response includes an entity?



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# File 'lib/webmachine/decision/flow.rb', line 484

def o20
  has_response_body? ? :o18 : 204
end

#p11 ⇒ Object

New resource?



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# File 'lib/webmachine/decision/flow.rb', line 499

def p11
  !response.headers["Location"] ? :o20 : 201
end

#p3 ⇒ Object

Conflict?



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# File 'lib/webmachine/decision/flow.rb', line 489

def p3
  if resource.is_conflict?
    409
  else
    res = accept_helper
    (Fixnum === res) ? res : :p11
  end
end