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
|
module ActionDispatch
class Request < Rack::Request
# Access the contents of the flash. Use <tt>flash["notice"]</tt> to
# read a notice you put there or <tt>flash["notice"] = "hello"</tt>
# to put a new one.
def flash
@env[Flash::KEY] ||= Flash::FlashHash.from_session_value(session["flash"])
end
end
# The flash provides a way to pass temporary objects between actions. Anything you place in the flash will be exposed
# to the very next action and then cleared out. This is a great way of doing notices and alerts, such as a create
# action that sets <tt>flash[:notice] = "Post successfully created"</tt> before redirecting to a display action that can
# then expose the flash to its template. Actually, that exposure is automatically done.
#
# class PostsController < ActionController::Base
# def create
# # save post
# flash[:notice] = "Post successfully created"
# redirect_to @post
# end
#
# def show
# # doesn't need to assign the flash notice to the template, that's done automatically
# end
# end
#
# show.html.erb
# <% if flash[:notice] %>
# <div class="notice"><%= flash[:notice] %></div>
# <% end %>
#
# Since the +notice+ and +alert+ keys are a common idiom, convenience accessors are available:
#
# flash.alert = "You must be logged in"
# flash.notice = "Post successfully created"
#
# This example just places a string in the flash, but you can put any object in there. And of course, you can put as
# many as you like at a time too. Just remember: They'll be gone by the time the next action has been performed.
#
# See docs on the FlashHash class for more details about the flash.
class Flash
KEY = 'action_dispatch.request.flash_hash'.freeze
class FlashNow #:nodoc:
attr_accessor :flash
def initialize(flash)
@flash = flash
end
def []=(k, v)
@flash[k] = v
@flash.discard(k)
v
end
def [](k)
@flash[k]
end
# Convenience accessor for flash.now[:alert]=
def alert=(message)
self[:alert] = message
end
# Convenience accessor for flash.now[:notice]=
def notice=(message)
self[:notice] = message
end
end
class FlashHash
include Enumerable
def self.from_session_value(value)
flash = case value
when FlashHash # Rails 3.1, 3.2
new(value.instance_variable_get(:@flashes), value.instance_variable_get(:@used))
when Hash # Rails 4.0
new(value['flashes'], value['discard'])
else
new
end
flash.tap(&:sweep)
end
def to_session_value
return nil if empty?
{'discard' => @discard.to_a, 'flashes' => @flashes}
end
def initialize(flashes = {}, discard = []) #:nodoc:
@discard = Set.new(discard)
@flashes = flashes
@now = nil
end
def initialize_copy(other)
if other.now_is_loaded?
@now = other.now.dup
@now.flash = self
end
super
end
def []=(k, v)
@discard.delete k
@flashes[k] = v
end
def [](k)
@flashes[k]
end
def update(h) #:nodoc:
@discard.subtract h.keys
@flashes.update h
self
end
def keys
@flashes.keys
end
def key?(name)
@flashes.key? name
end
def delete(key)
@discard.delete key
@flashes.delete key
self
end
def to_hash
@flashes.dup
end
def empty?
@flashes.empty?
end
def clear
@discard.clear
@flashes.clear
end
def each(&block)
@flashes.each(&block)
end
alias :merge! :update
def replace(h) #:nodoc:
@discard.clear
@flashes.replace h
self
end
# Sets a flash that will not be available to the next action, only to the current.
#
# flash.now[:message] = "Hello current action"
#
# This method enables you to use the flash as a central messaging system in your app.
# When you need to pass an object to the next action, you use the standard flash assign (<tt>[]=</tt>).
# When you need to pass an object to the current action, you use <tt>now</tt>, and your object will
# vanish when the current action is done.
#
# Entries set via <tt>now</tt> are accessed the same way as standard entries: <tt>flash['my-key']</tt>.
def now
@now ||= FlashNow.new(self)
end
# Keeps either the entire current flash or a specific flash entry available for the next action:
#
# flash.keep # keeps the entire flash
# flash.keep(:notice) # keeps only the "notice" entry, the rest of the flash is discarded
def keep(k = nil)
@discard.subtract Array(k || keys)
k ? self[k] : self
end
# Marks the entire flash or a single flash entry to be discarded by the end of the current action:
#
# flash.discard # discard the entire flash at the end of the current action
# flash.discard(:warning) # discard only the "warning" entry at the end of the current action
def discard(k = nil)
@discard.merge Array(k || keys)
k ? self[k] : self
end
# Mark for removal entries that were kept, and delete unkept ones.
#
# This method is called automatically by filters, so you generally don't need to care about it.
def sweep #:nodoc:
@discard.each { |k| @flashes.delete k }
@discard.replace @flashes.keys
end
# Convenience accessor for flash[:alert]
def alert
self[:alert]
end
# Convenience accessor for flash[:alert]=
def alert=(message)
self[:alert] = message
end
# Convenience accessor for flash[:notice]
def notice
self[:notice]
end
# Convenience accessor for flash[:notice]=
def notice=(message)
self[:notice] = message
end
protected
def now_is_loaded?
@now
end
end
def initialize(app)
@app = app
end
def call(env)
@app.call(env)
ensure
session = Request::Session.find(env) || {}
flash_hash = env[KEY]
if flash_hash
if !flash_hash.empty? || session.key?('flash')
session["flash"] = flash_hash.to_session_value
new_hash = flash_hash.dup
else
new_hash = flash_hash
end
env[KEY] = new_hash
end
if (!session.respond_to?(:loaded?) || session.loaded?) && # (reset_session uses {}, which doesn't implement #loaded?)
session.key?('flash') && session['flash'].nil?
session.delete('flash')
end
end
end
end
|