aboutsummaryrefslogtreecommitdiffstats
path: root/actionwebservice/lib/action_web_service/api.rb
blob: 73fb886e6d7ec361b9267e7ed99ebbfd730fb537 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
module ActionWebService # :nodoc:
  module API # :nodoc:
    # A web service API class specifies the methods that will be available for
    # invocation for an API. It also contains metadata such as the method type
    # signature hints.
    #
    # It is not intended to be instantiated.
    #
    # It is attached to web service implementation classes like
    # ActionWebService::Base and ActionController::Base derivatives by using
    # <tt>container.web_service_api</tt>, where <tt>container</tt> is an
    # ActionController::Base or a ActionWebService::Base.
    #
    # See ActionWebService::Container::Direct::ClassMethods for an example
    # of use.
    class Base
      # Action WebService API subclasses should be reloaded by the dispatcher in Rails
      # when Dependencies.mechanism = :load.
      include Reloadable::Deprecated
      
      # Whether to transform the public API method names into camel-cased names 
      class_inheritable_option :inflect_names, true

      # Whether to allow ActiveRecord::Base models in <tt>:expects</tt>.
      # The default is +false+; you should be aware of the security implications
      # of allowing this, and ensure that you don't allow remote callers to
      # easily overwrite data they should not have access to.
      class_inheritable_option :allow_active_record_expects, false

      # If present, the name of a method to call when the remote caller
      # tried to call a nonexistent method. Semantically equivalent to
      # +method_missing+.
      class_inheritable_option :default_api_method

      # Disallow instantiation
      private_class_method :new, :allocate
      
      class << self
        include ActionWebService::SignatureTypes

        # API methods have a +name+, which must be the Ruby method name to use when
        # performing the invocation on the web service object.
        #
        # The signatures for the method input parameters and return value can
        # by specified in +options+.
        #
        # A signature is an array of one or more parameter specifiers. 
        # A parameter specifier can be one of the following:
        #
        # * A symbol or string representing one of the Action Web Service base types.
        #   See ActionWebService::SignatureTypes for a canonical list of the base types.
        # * The Class object of the parameter type
        # * A single-element Array containing one of the two preceding items. This
        #   will cause Action Web Service to treat the parameter at that position
        #   as an array containing only values of the given type.
        # * A Hash containing as key the name of the parameter, and as value
        #   one of the three preceding items
        # 
        # If no method input parameter or method return value signatures are given,
        # the method is assumed to take no parameters and/or return no values of
        # interest, and any values that are received by the server will be
        # discarded and ignored.
        #
        # Valid options:
        # [<tt>:expects</tt>]             Signature for the method input parameters
        # [<tt>:returns</tt>]             Signature for the method return value
        # [<tt>:expects_and_returns</tt>] Signature for both input parameters and return value
        def api_method(name, options={})
          unless options.is_a?(Hash)
            raise(ActionWebServiceError, "Expected a Hash for options")
          end
          validate_options([:expects, :returns, :expects_and_returns], options.keys)
          if options[:expects_and_returns]
            expects = options[:expects_and_returns]
            returns = options[:expects_and_returns]
          else
            expects = options[:expects]
            returns = options[:returns]
          end
          expects = canonical_signature(expects)
          returns = canonical_signature(returns)
          if expects
            expects.each do |type|
              type = type.element_type if type.is_a?(ArrayType)
              if type.type_class.ancestors.include?(ActiveRecord::Base) && !allow_active_record_expects
                raise(ActionWebServiceError, "ActiveRecord model classes not allowed in :expects")
              end
            end
          end
          name = name.to_sym
          public_name = public_api_method_name(name)
          method = Method.new(name, public_name, expects, returns)
          write_inheritable_hash("api_methods", name => method)
          write_inheritable_hash("api_public_method_names", public_name => name)
        end

        # Whether the given method name is a service method on this API
        def has_api_method?(name)
          api_methods.has_key?(name)
        end
  
        # Whether the given public method name has a corresponding service method
        # on this API
        def has_public_api_method?(public_name)
          api_public_method_names.has_key?(public_name)
        end
  
        # The corresponding public method name for the given service method name
        def public_api_method_name(name)
          if inflect_names
            name.to_s.camelize
          else
            name.to_s
          end
        end
  
        # The corresponding service method name for the given public method name
        def api_method_name(public_name)
          api_public_method_names[public_name]
        end
  
        # A Hash containing all service methods on this API, and their
        # associated metadata.
        def api_methods
          read_inheritable_attribute("api_methods") || {}
        end

        # The Method instance for the given public API method name, if any
        def public_api_method_instance(public_method_name)
          api_method_instance(api_method_name(public_method_name))
        end

        # The Method instance for the given API method name, if any
        def api_method_instance(method_name)
          api_methods[method_name]
        end

        # The Method instance for the default API method, if any
        def default_api_method_instance
          return nil unless name = default_api_method
          instance = read_inheritable_attribute("default_api_method_instance")
          if instance && instance.name == name
            return instance
          end
          instance = Method.new(name, public_api_method_name(name), nil, nil)
          write_inheritable_attribute("default_api_method_instance", instance)
          instance
        end

        private
          def api_public_method_names
            read_inheritable_attribute("api_public_method_names") || {}
          end
  
          def validate_options(valid_option_keys, supplied_option_keys)
            unknown_option_keys = supplied_option_keys - valid_option_keys
            unless unknown_option_keys.empty?
              raise(ActionWebServiceError, "Unknown options: #{unknown_option_keys}")
            end
          end
      end
    end

    # Represents an API method and its associated metadata, and provides functionality
    # to assist in commonly performed API method tasks.
    class Method
      attr :name
      attr :public_name
      attr :expects
      attr :returns

      def initialize(name, public_name, expects, returns)
        @name = name
        @public_name = public_name
        @expects = expects
        @returns = returns
        @caster = ActionWebService::Casting::BaseCaster.new(self)
      end
      
      # The list of parameter names for this method
      def param_names
        return [] unless @expects
        @expects.map{ |type| type.name }
      end

      # Casts a set of Ruby values into the expected Ruby values
      def cast_expects(params)
        @caster.cast_expects(params)
      end

      # Cast a Ruby return value into the expected Ruby value
      def cast_returns(return_value)
        @caster.cast_returns(return_value)
      end

      # Returns the index of the first expected parameter
      # with the given name
      def expects_index_of(param_name)
        return -1 if @expects.nil?
        (0..(@expects.length-1)).each do |i|
          return i if @expects[i].name.to_s == param_name.to_s
        end
        -1
      end

      # Returns a hash keyed by parameter name for the given
      # parameter list
      def expects_to_hash(params)
        return {} if @expects.nil?
        h = {}
        @expects.zip(params){ |type, param| h[type.name] = param }
        h
      end

      # Backwards compatibility with previous API
      def [](sig_type)
        case sig_type
        when :expects
          @expects.map{|x| compat_signature_entry(x)}
        when :returns
          @returns.map{|x| compat_signature_entry(x)}
        end
      end

      # String representation of this method
      def to_s
        fqn = ""
        fqn << (@returns ? (@returns[0].human_name(false) + " ") : "void ")
        fqn << "#{@public_name}("
        fqn << @expects.map{ |p| p.human_name }.join(", ") if @expects
        fqn << ")"
        fqn
      end

      private
        def compat_signature_entry(entry)
          if entry.array?
            [compat_signature_entry(entry.element_type)]
          else
            if entry.spec.is_a?(Hash)
              {entry.spec.keys.first => entry.type_class}
            else
              entry.type_class
            end
          end
        end
    end
  end
end