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|
#
# borrowed from http://github.com/nakajima/rack-flash - thanks!
#
require 'rack/builder'
module Rack
class Builder
attr :ins
def use(middleware, *args, &block)
middleware.instance_variable_set "@rack_builder", self
def middleware.rack_builder
@rack_builder
end
@ins << Proc.new { |app|
middleware.new(app, *args, &block)
}
end
def run(app)
klass = app.class
klass.instance_variable_set "@rack_builder", self
def klass.rack_builder
@rack_builder
end
@ins << app #lambda { |nothing| app }
end
def leaf_app
ins.last
end
end
end
module Rack
class Flash
# Raised when the session passed to FlashHash initialize is nil. This
# is usually an indicator that session middleware is not in use.
class SessionUnavailable < StandardError; end
# Implements bracket accessors for storing and retrieving flash entries.
class FlashHash
attr_reader :flagged
def initialize(store, opts={})
raise Rack::Flash::SessionUnavailable \
.new('Rack::Flash depends on session middleware.') unless store
@opts = opts
@store = store
if accessors = @opts[:accessorize]
accessors.each { |opt| def_accessor(opt) }
end
end
# Remove an entry from the session and return its value. Cache result in
# the instance cache.
def [](key)
key = key.to_sym
cache[key] ||= values.delete(key)
end
# Store the entry in the session, updating the instance cache as well.
def []=(key,val)
key = key.to_sym
cache[key] = values[key] = val
end
# Store a flash entry for only the current request, swept regardless of
# whether or not it was actually accessed. Useful for AJAX requests, where
# you want a flash message, even though you're response isn't redirecting.
def now
cache
end
# Checks for the presence of a flash entry without retrieving or removing
# it from the cache or store.
def has?(key)
[cache, values].any? { |store| store.keys.include?(key.to_sym) }
end
alias_method :include?, :has?
# Mark existing entries to allow for sweeping.
def flag!
@flagged = values.keys
end
# Remove flagged entries from flash session, clear flagged list.
def sweep!
Array(flagged).each { |key| values.delete(key) }
flagged.clear
end
# Hide the underlying :__FLASH__ session key and only expose values stored
# in the flash.
def inspect
'#<FlashHash @values=%s @cache=%s>' % [values.inspect, cache.inspect]
end
# Human readable for logging.
def to_s
values.inspect
end
private
# Maintain an instance-level cache of retrieved flash entries. These
# entries will have been removed from the session, but are still available
# through the cache.
def cache
@cache ||= {}
end
# Helper to access flash entries from :__FLASH__ session value. This key
# is used to prevent collisions with other user-defined session values.
def values
@store[:__FLASH__] ||= {}
end
# Generate accessor methods for the given entry key if :accessorize is true.
def def_accessor(key)
raise ArgumentError.new('Invalid entry type: %s' % key) if respond_to?(key)
class << self; self end.class_eval do
define_method(key) { |*args| val = args.first; val ? (self[key]=val) : self[key] }
define_method("#{key}=") { |val| self[key] = val }
define_method("#{key}!") { |val| cache[key] = val }
end
end
end
# -------------------------------------------------------------------------
# - Rack Middleware implementation
def initialize(app, opts={})
if klass = app_class(app, opts)
klass.class_eval do
def flash; env['x-rack.flash'] end
end
end
@app, @opts = app, opts
end
def call(env)
env['x-rack.flash'] ||= Rack::Flash::FlashHash.new(env['rack.session'], @opts)
if @opts[:sweep]
env['x-rack.flash'].flag!
end
res = @app.call(env)
if @opts[:sweep]
env['x-rack.flash'].sweep!
end
res
end
private
def app_class(app, opts)
return nil if opts.has_key?(:helper) and not opts[:helper]
opts[:flash_app_class] ||
defined?(Sinatra::Base) && Sinatra::Base ||
self.class.rack_builder.leaf_app.class
end
end
end
|
