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module ActionController #:nodoc:
module Verification #:nodoc:
def self.included(base) #:nodoc:
base.extend(ClassMethods)
end
# This module provides a class-level method for specifying that certain
# actions are guarded against being called without certain prerequisites
# being met. This is essentially a special kind of before_filter.
#
# An action may be guarded against being invoked without certain request
# parameters being set, or without certain session values existing.
#
# When a verification is violated, values may be inserted into the flash, and
# a specified redirection is triggered.
#
# Usage:
#
# class GlobalController < ActionController::Base
# # Prevent the #update_settings action from being invoked unless
# # the 'admin_privileges' request parameter exists. The
# # settings action will be redirected to in current controller
# # if verification fails.
# verify :params => "admin_privileges", :only => :update_post,
# :redirect_to => { :action => "settings" }
#
# # Disallow a post from being updated if there was no information
# # submitted with the post, and if there is no active post in the
# # session, and if there is no "note" key in the flash. The route
# # named category_url will be redirected to if verification fails.
#
# verify :params => "post", :session => "post", "flash" => "note",
# :only => :update_post,
# :add_flash => { "alert" => "Failed to create your message" },
# :redirect_to => :category_url
#
# Note that these prerequisites are not business rules. They do not examine
# the content of the session or the parameters. That level of validation should
# be encapsulated by your domain model or helper methods in the controller.
module ClassMethods
# Verify the given actions so that if certain prerequisites are not met,
# the user is redirected to a different action. The +options+ parameter
# is a hash consisting of the following key/value pairs:
#
# * <tt>:params</tt>: a single key or an array of keys that must
# be in the <tt>params</tt> hash in order for the action(s) to be safely
# called.
# * <tt>:session</tt>: a single key or an array of keys that must
# be in the <tt>session</tt> in order for the action(s) to be safely called.
# * <tt>:flash</tt>: a single key or an array of keys that must
# be in the flash in order for the action(s) to be safely called.
# * <tt>:method</tt>: a single key or an array of keys--any one of which
# must match the current request method in order for the action(s) to
# be safely called. (The key should be a symbol: <tt>:get</tt> or
# <tt>:post</tt>, for example.)
# * <tt>:xhr</tt>: true/false option to ensure that the request is coming
# from an Ajax call or not.
# * <tt>:add_flash</tt>: a hash of name/value pairs that should be merged
# into the session's flash if the prerequisites cannot be satisfied.
# * <tt>:add_headers</tt>: a hash of name/value pairs that should be
# merged into the response's headers hash if the prerequisites cannot
# be satisfied.
# * <tt>:redirect_to</tt>: the redirection parameters to be used when
# redirecting if the prerequisites cannot be satisfied. You can
# redirect either to named route or to the action in some controller.
# * <tt>:render</tt>: the render parameters to be used when
# the prerequisites cannot be satisfied.
# * <tt>:only</tt>: only apply this verification to the actions specified
# in the associated array (may also be a single value).
# * <tt>:except</tt>: do not apply this verification to the actions
# specified in the associated array (may also be a single value).
def verify(options={})
filter_opts = { :only => options[:only], :except => options[:except] }
before_filter(filter_opts) do |c|
c.send :verify_action, options
end
end
end
def verify_action(options) #:nodoc:
prereqs_invalid =
[*options[:params] ].find { |v| params[v].nil? } ||
[*options[:session]].find { |v| session[v].nil? } ||
[*options[:flash] ].find { |v| flash[v].nil? }
if !prereqs_invalid && options[:method]
prereqs_invalid ||=
[*options[:method]].all? { |v| request.method != v.to_sym }
end
prereqs_invalid ||= (request.xhr? != options[:xhr]) unless options[:xhr].nil?
if prereqs_invalid
flash.update(options[:add_flash]) if options[:add_flash]
response.headers.update(options[:add_headers]) if options[:add_headers]
unless performed?
render(options[:render]) if options[:render]
redirect_to(options[:redirect_to]) if options[:redirect_to]
end
return false
end
true
end
private :verify_action
end
end
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