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
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
|
module ActionController #:nodoc:
module MimeResponds #:nodoc:
extend ActiveSupport::Concern
included do
class_inheritable_reader :mimes_for_respond_to
clear_respond_to
end
module ClassMethods
# Defines mimes that are rendered by default when invoking respond_with.
#
# Examples:
#
# respond_to :html, :xml, :json
#
# All actions on your controller will respond to :html, :xml and :json.
#
# But if you want to specify it based on your actions, you can use only and
# except:
#
# respond_to :html
# respond_to :xml, :json, :except => [ :edit ]
#
# The definition above explicits that all actions respond to :html. And all
# actions except :edit respond to :xml and :json.
#
# You can specify also only parameters:
#
# respond_to :rjs, :only => :create
#
def respond_to(*mimes)
options = mimes.extract_options!
only_actions = Array(options.delete(:only))
except_actions = Array(options.delete(:except))
mimes.each do |mime|
mime = mime.to_sym
mimes_for_respond_to[mime] = {}
mimes_for_respond_to[mime][:only] = only_actions unless only_actions.empty?
mimes_for_respond_to[mime][:except] = except_actions unless except_actions.empty?
end
end
# Clear all mimes in respond_to.
#
def clear_respond_to
write_inheritable_attribute(:mimes_for_respond_to, ActiveSupport::OrderedHash.new)
end
end
# Without web-service support, an action which collects the data for displaying a list of people
# might look something like this:
#
# def index
# @people = Person.find(:all)
# end
#
# Here's the same action, with web-service support baked in:
#
# def index
# @people = Person.find(:all)
#
# respond_to do |format|
# format.html
# format.xml { render :xml => @people.to_xml }
# end
# end
#
# What that says is, "if the client wants HTML in response to this action, just respond as we
# would have before, but if the client wants XML, return them the list of people in XML format."
# (Rails determines the desired response format from the HTTP Accept header submitted by the client.)
#
# Supposing you have an action that adds a new person, optionally creating their company
# (by name) if it does not already exist, without web-services, it might look like this:
#
# def create
# @company = Company.find_or_create_by_name(params[:company][:name])
# @person = @company.people.create(params[:person])
#
# redirect_to(person_list_url)
# end
#
# Here's the same action, with web-service support baked in:
#
# def create
# company = params[:person].delete(:company)
# @company = Company.find_or_create_by_name(company[:name])
# @person = @company.people.create(params[:person])
#
# respond_to do |format|
# format.html { redirect_to(person_list_url) }
# format.js
# format.xml { render :xml => @person.to_xml(:include => @company) }
# end
# end
#
# If the client wants HTML, we just redirect them back to the person list. If they want Javascript
# (format.js), then it is an RJS request and we render the RJS template associated with this action.
# Lastly, if the client wants XML, we render the created person as XML, but with a twist: we also
# include the person's company in the rendered XML, so you get something like this:
#
# <person>
# <id>...</id>
# ...
# <company>
# <id>...</id>
# <name>...</name>
# ...
# </company>
# </person>
#
# Note, however, the extra bit at the top of that action:
#
# company = params[:person].delete(:company)
# @company = Company.find_or_create_by_name(company[:name])
#
# This is because the incoming XML document (if a web-service request is in process) can only contain a
# single root-node. So, we have to rearrange things so that the request looks like this (url-encoded):
#
# person[name]=...&person[company][name]=...&...
#
# And, like this (xml-encoded):
#
# <person>
# <name>...</name>
# <company>
# <name>...</name>
# </company>
# </person>
#
# In other words, we make the request so that it operates on a single entity's person. Then, in the action,
# we extract the company data from the request, find or create the company, and then create the new person
# with the remaining data.
#
# Note that you can define your own XML parameter parser which would allow you to describe multiple entities
# in a single request (i.e., by wrapping them all in a single root node), but if you just go with the flow
# and accept Rails' defaults, life will be much easier.
#
# If you need to use a MIME type which isn't supported by default, you can register your own handlers in
# environment.rb as follows.
#
# Mime::Type.register "image/jpg", :jpg
#
# Respond to also allows you to specify a common block for different formats by using any:
#
# def index
# @people = Person.find(:all)
#
# respond_to do |format|
# format.html
# format.any(:xml, :json) { render request.format.to_sym => @people }
# end
# end
#
# In the example above, if the format is xml, it will render:
#
# render :xml => @people
#
# Or if the format is json:
#
# render :json => @people
#
# Since this is a common pattern, you can use the class method respond_to
# with the respond_with method to have the same results:
#
# class PeopleController < ApplicationController
# respond_to :html, :xml, :json
#
# def index
# @people = Person.find(:all)
# respond_with(@person)
# end
# end
#
# Be sure to check respond_with and respond_to documentation for more examples.
#
def respond_to(*mimes, &block)
raise ArgumentError, "respond_to takes either types or a block, never both" if mimes.any? && block_given?
responder = Responder.new
mimes = collect_mimes_from_class_level if mimes.empty?
mimes.each { |mime| responder.send(mime) }
block.call(responder) if block_given?
if format = request.negotiate_mime(responder.order)
self.formats = [format.to_sym]
if response = responder.response_for(format)
response.call
else
default_render
end
else
head :not_acceptable
end
end
# respond_with allows you to respond an action with a given resource. It
# requires that you set your class with a :respond_to method with the
# formats allowed:
#
# class PeopleController < ApplicationController
# respond_to :html, :xml, :json
#
# def index
# @people = Person.find(:all)
# respond_with(@person)
# end
# end
#
# When a request comes with format :xml, the respond_with will first search
# for a template as person/index.xml, if the template is not available, it
# will see if the given resource responds to :to_xml.
#
# If neither are available, it will raise an error.
#
# Extra parameters given to respond_with are used when :to_format is invoked.
# This allows you to set status and location for several formats at the same
# time. Consider this restful controller response on create for both xml
# and json formats:
#
# class PeopleController < ApplicationController
# respond_to :xml, :json
#
# def create
# @person = Person.new(params[:person])
#
# if @person.save
# respond_with(@person, :status => :ok, :location => person_url(@person))
# else
# respond_with(@person.errors, :status => :unprocessable_entity)
# end
# end
# end
#
# Finally, respond_with also accepts blocks, as in respond_to. Let's take
# the same controller and create action above and add common html behavior:
#
# class PeopleController < ApplicationController
# respond_to :html, :xml, :json
#
# def create
# @person = Person.new(params[:person])
#
# if @person.save
# options = { :status => :ok, :location => person_url(@person) }
#
# respond_with(@person, options) do |format|
# format.html { redirect_to options[:location] }
# end
# else
# respond_with(@person.errors, :status => :unprocessable_entity) do
# format.html { render :action => :new }
# end
# end
# end
# end
#
def respond_with(resource, options={}, &block)
begin
respond_to(&block)
rescue ActionView::MissingTemplate => e
format = self.formats.first
if resource.respond_to?(:"to_#{format}")
render options.merge(format => resource)
else
raise e
end
end
end
protected
# Collect mimes declared in the class method respond_to valid for the
# current action.
#
def collect_mimes_from_class_level #:nodoc:
action = action_name.to_sym
mimes_for_respond_to.keys.select do |mime|
config = mimes_for_respond_to[mime]
if config[:except]
!config[:except].include?(action)
elsif config[:only]
config[:only].include?(action)
else
true
end
end
end
class Responder #:nodoc:
attr_accessor :order
def initialize
@order, @responses = [], {}
end
def any(*args, &block)
if args.any?
args.each { |type| send(type, &block) }
else
custom(Mime::ALL, &block)
end
end
alias :all :any
def custom(mime_type, &block)
mime_type = mime_type.is_a?(Mime::Type) ? mime_type : Mime::Type.lookup(mime_type.to_s)
@order << mime_type
@responses[mime_type] ||= block
end
def response_for(mime)
@responses[mime] || @responses[Mime::ALL]
end
def self.generate_method_for_mime(mime)
sym = mime.is_a?(Symbol) ? mime : mime.to_sym
const = sym.to_s.upcase
class_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{sym}(&block) # def html(&block)
custom(Mime::#{const}, &block) # custom(Mime::HTML, &block)
end # end
RUBY
end
Mime::SET.each do |mime|
generate_method_for_mime(mime)
end
def method_missing(symbol, &block)
mime_constant = Mime.const_get(symbol.to_s.upcase)
if Mime::SET.include?(mime_constant)
self.class.generate_method_for_mime(mime_constant)
send(symbol, &block)
else
super
end
end
end
end
end
|