我只是想帮助找出答案。我自己跟踪了源代码，这有助于我理解:event => :authentication 参数的工作原理。希望对你也有帮助。
所以你的问题是为什么
将 :event => :authentication 传递给 sign_in_and_redirect 方法以强制调用所有身份验证回调。
然后，我们可以跟踪定义。
# Sign in a user and tries to redirect first to the stored location and
# then to the url specified by after_sign_in_path_for. It accepts the same
# parameters as the sign_in method.
def sign_in_and_redirect(resource_or_scope, *args)
options = args.extract_options!
scope = Devise::Mapping.find_scope!(resource_or_scope)
resource = args.last || resource_or_scope
sign_in(scope, resource, options)
redirect_to after_sign_in_path_for(resource)
end
然后sign_in在设计中定义：
# All options given to sign_in is passed forward to the set_user method in warden.
# The only exception is the :bypass option, which bypass warden callbacks and stores
# the user straight in session. This option is useful in cases the user is already
# signed in, but we want to refresh the credentials in session.
#
# Examples:
#
# sign_in :user, @user # sign_in(scope, resource)
# sign_in @user # sign_in(resource)
# sign_in @user, :event => :authentication # sign_in(resource, options)
# sign_in @user, :bypass => true # sign_in(resource, options)
#
def sign_in(resource_or_scope, *args)
options = args.extract_options!
scope = Devise::Mapping.find_scope!(resource_or_scope)
resource = args.last || resource_or_scope
expire_session_data_after_sign_in!
if options[:bypass]
warden.session_serializer.store(resource, scope)
elsif warden.user(scope) == resource && !options.delete(:force)
# Do nothing. User already signed in and we are not forcing it.
true
else
warden.set_user(resource, options.merge!(:scope => scope))
end
end
好的，所以:event => :authentication 现在传递给warden#set_user，那么你的问题就变成了为什么
将 :event => :authentication 传递给 sign_in_and_redirect 方法以强制调用所有身份验证回调。
# Manually set the user into the session and auth proxy
#
# Parameters:
# user - An object that has been setup to serialize into and out of the session.
# opts - An options hash. Use the :scope option to set the scope of the user, set the :store option to false to skip serializing into the session, set the :run_callbacks to false to skip running the callbacks (the default is true).
#
# :api: public
def set_user(user, opts = {})
scope = (opts[:scope] ||= @config.default_scope)
# Get the default options from the master configuration for the given scope
opts = (@config[:scope_defaults][scope] || {}).merge(opts)
opts[:event] ||= :set_user
@users[scope] = user
if opts[:store] != false && opts[:event] != :fetch
options = env[ENV_SESSION_OPTIONS]
options[:renew] = true if options
session_serializer.store(user, scope)
end
run_callbacks = opts.fetch(:run_callbacks, true)
manager._run_callbacks(:after_set_user, user, self, opts) if run_callbacks
@users[scope]
end
opts[:event] 可以是[:set_user, :fetch, :authentication]
# Hook to _run_callbacks asserting for conditions.
def _run_callbacks(kind, *args) #:nodoc:
options = args.last # Last callback arg MUST be a Hash
send("_#{kind}").each do |callback, conditions|
invalid = conditions.find do |key, value|
value.is_a?(Array) ? !value.include?(options[key]) : (value != options[key])
end
callback.call(*args) unless invalid
end
end
# A callback hook set to run every time after a user is set.
# This callback is triggered the first time one of those three events happens
# during a request: :authentication, :fetch (from session) and :set_user (when manually set).
# You can supply as many hooks as you like, and they will be run in order of decleration.
#
# If you want to run the callbacks for a given scope and/or event, you can specify them as options.
# See parameters and example below.
#
# Parameters:
# <options> Some options which specify when the callback should be executed
# scope - Executes the callback only if it maches the scope(s) given
# only - Executes the callback only if it matches the event(s) given
# except - Executes the callback except if it matches the event(s) given
# <block> A block where you can set arbitrary logic to run every time a user is set
# Block Parameters: |user, auth, opts|
# user - The user object that is being set
# auth - The raw authentication proxy object.
# opts - any options passed into the set_user call includeing :scope
#
# Example:
# Warden::Manager.after_set_user do |user,auth,opts|
# scope = opts[:scope]
# if auth.session["#{scope}.last_access"].to_i > (Time.now - 5.minutes)
# auth.logout(scope)
# throw(:warden, :scope => scope, :reason => "Times Up")
# end
# auth.session["#{scope}.last_access"] = Time.now
# end
#
# Warden::Manager.after_set_user :except => :fetch do |user,auth,opts|
# user.login_count += 1
# end
#
# :api: public
def after_set_user(options = {}, method = :push, &block)
raise BlockNotGiven unless block_given?
if options.key?(:only)
options[:event] = options.delete(:only)
elsif options.key?(:except)
options[:event] = [:set_user, :authentication, :fetch] - Array(options.delete(:except))
end
_after_set_user.send(method, [block, options])
end
所以，
# after_authentication is just a wrapper to after_set_user, which is only invoked
# when the user is set through the authentication path. The options and yielded arguments
# are the same as in after_set_user.
#
# :api: public
def after_authentication(options = {}, method = :push, &block)
after_set_user(options.merge(:event => :authentication), method, &block)
end