如何在Rails 4中为Facebook omniauth保存request.referrer

Question

我的应用程序中有两个Facebook按钮。 一个在users/sign_up ，另一个在/visitors/owner-faq 。 我想保存request.referrer以便知道用户从哪个页面进行了注册。 我已经为外部注册（使用表单）实现了相同的功能，并且可以正常工作。 现在，我无法为facebook omniauth实现相同的功能 。

码：

#user.rb

def self.from_omniauth(auth) 
    email         = auth.info.email 
    user          = User.find_by_email(email)   # first tries to find an existing user who signed up normal way with the same email to sign them in 
    if user && user.confirmed?                
      user.provider = auth.provider
      user.uid      = auth.uid
      return user
    end

    where(provider: auth.provider, uid: auth.uid).first_or_create do |user|  # then tries to find the user who authenticated through FB, and if
      user.email            = auth.info.email                                # not present, creates that user
      user.password         = Devise.friendly_token[0,20]
      user.first_name       = auth.info.first_name
      user.last_name        = auth.info.last_name
      user.social_photo_url = auth.info.image
      user.skip_confirmation!   
    end
  end

#users/omniauth_callbacks_controller

def facebook
    @user = User.from_omniauth(request.env["omniauth.auth"])

    if @user.persisted?
      sign_in_and_redirect @user, :event => :authentication #this will throw if @user is not activated
      set_flash_message(:notice, :success, :kind => "Facebook") if is_navigational_format?
    else
      session["devise.facebook_data"] = request.env["omniauth.auth"]
      Rails.logger.info(@user.errors.inspect) 
      redirect_to new_user_registration_url
    end
  end

#application_controller.rb

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception
  before_filter :store_referrer_url, :only => [:new]

  private

  def store_referrer_url
    session[:referrer] = URI(request.referer).path
  end
end

尝试1：

我设法将request.referrer这样保存在users/omniauth_callbacks_controller

def facebook
    @user = User.from_omniauth(request.env["omniauth.auth"])
    @user.referrer_url = session[:referrer] #here
    @user.save!

    if @user.persisted?
      sign_in_and_redirect @user, :event => :authentication #this will throw if @user is not activated
      set_flash_message(:notice, :success, :kind => "Facebook") if is_navigational_format?
    else
      session["devise.facebook_data"] = request.env["omniauth.auth"]
      Rails.logger.info(@user.errors.inspect) 
      redirect_to new_user_registration_url
    end
  end

但是这里的问题是，当现有用户从另一个页面登录时， referrer_url的值将被覆盖 。 我不想覆盖referrer_url 。

尝试2：

我试图将request.referrer保存在from_omniauth(auth)方法User模型中，如下所示

def self.from_omniauth(auth) 
    email         = auth.info.email 
    user          = User.find_by_email(email)   # first tries to find an existing user who signed up normal way with the same email to sign them in 
    if user && user.confirmed?                
      user.provider = auth.provider
      user.uid      = auth.uid
      return user
    end

    where(provider: auth.provider, uid: auth.uid).first_or_create do |user|  # then tries to find the user who authenticated through FB, and if
      user.email            = auth.info.email                                # not present, creates that user
      user.password         = Devise.friendly_token[0,20]
      user.first_name       = auth.info.first_name
      user.last_name        = auth.info.last_name
      user.social_photo_url = auth.info.image
      user.referrer_url     = session[:referrer]
      user.skip_confirmation!   
    end
  end

但这给了我这个错误

undefined local variable or method `session' for #<Class:0x0000000e1c46f8>

任何建议将大有帮助。

Answer 1

如果希望referrer_url属性在首次设置后保持不变，则应使用OR Equal运算符，该运算符只会在当前值为nil或false设置该值：

@user.referrer_url ||= session[:referrer]

如果我理解正确，那么在注册和登录时都会调用您的facebook回调，并且该值当然会被覆盖。 设置值后，或等于将防止覆盖该值。

关于尝试2 ，会话哈希仅在控制器和视图中可用，因此您不能在模型中使用它。

另一种可能性 ：

您要在store_referrer_url方法中设置session[:referrer] ， store_referrer_url方法在new方法的before_filter回调中调用。

您的登录很有可能也是使用new方法进行的（例如，在Devise中，它将在SessionsController ），因此再次调用该回调并覆盖该值（所有Devise控制器都继承自您的ApplicationController ）。 在这种情况下，您可以从ApplicationController取出before_filter回调到正在处理RegistrationsController的控制器（将是带有Devise的RegistrationsController ）。