【发布时间】：2015-03-06 19:57:44
【问题描述】：
似乎无法为此找到有效的答案。我在 Rails 教程的第 10 章第 10.1.2 节，似乎无法让邮件预览工作。我发现处理该错误的所有答案都与本教程的不同部分有关，我假设我所犯的错误正盯着我看。我已经浏览并将教程中的代码复制/粘贴到相关文件中，到目前为止，我还无法看到我输入的内容与教程中的内容之间的区别。到目前为止，建议是在函数定义中添加或删除参数user，但这并没有解决问题。触发错误的 url 是http://localhost:3000/rails/mailers/user_mailer/account_activation。 http://localhost:3000/rails/mailers/user_mailer/ 没有问题，http://localhost:3000/rails/mailers/user_mailer/password_reset 也没有问题（我还没有对其进行任何定制）。我错过了什么？
这是错误：
NoMethodError in Rails::MailersController#preview
undefined method `activation_token=' for nil:NilClass
提取来源：
def account_activation
user = User.first
user.activation_token = User.new_token # highlighted line
UserMailer.account_activation(user)
end
据我所知，这里涉及的文件是：
user_mailer.rb:
class UserMailer < ApplicationMailer
# Subject can be set in your I18n file at config/locales/en.yml
# with the following lookup:
#
# en.user_mailer.account_activation.subject
#
def account_activation(user)
@user = user
mail to: user.email, subject: "Account activation"
end
def password_reset
@greeting = "Hi"
mail to: "to@example.org"
end
end
user_mailer_preview.rb:
# Preview all emails at http://localhost:3000/rails/mailers/user_mailer
class UserMailerPreview < ActionMailer::Preview
# Preview this email at http://localhost:3000/rails/mailers/user_mailer/account_activation
def account_activation
user = User.first
user.activation_token = User.new_token
UserMailer.account_activation(user)
end
# Preview this email at http://localhost:3000/rails/mailers/user_mailer/password_reset
def password_reset
UserMailer.password_reset
end
end
开发.rb：
Rails.application.configure do
config.cache_classes = false
# Do not eager load code on boot.
config.eager_load = false
# Show full error reports and disable caching.
config.consider_all_requests_local = true
config.action_controller.perform_caching = false
# Don't care if the mailer can't send.
config.action_mailer.raise_delivery_errors = true
config.action_mailer.delivery_method = :test
host = 'localhost:3000'
config.action_mailer.default_url_options = { host: host }
# Print deprecation notices to the Rails logger.
config.active_support.deprecation = :log
# Raise an error on page load if there are pending migrations.
config.active_record.migration_error = :page_load
# Debug mode disables concatenation and preprocessing of assets.
# This option may cause significant delays in view rendering with a large
# number of complex assets.
config.assets.debug = true
# Asset digests allow you to set far-future HTTP expiration dates on all assets,
# yet still be able to expire them through the digest params.
config.assets.digest = true
# Adds additional error checking when serving assets at runtime.
# Checks for improperly declared sprockets dependencies.
# Raises helpful error messages.
config.assets.raise_runtime_errors = true
# Raises error for missing translations
# config.action_view.raise_on_missing_translations = true
end
为了完整起见，这里是视图和我的用户模型：
account_activation.html.erb：
<h1>Sample App</h1>
<p>Hi <%= @user.name %>,</p>
<p>
Welcome to the Sample App! Click on the link below to activate your account:
</p>
<%= link_to "Activate", edit_account_activation_url(@user.activation_token,
email: @user.email) %>
account_activation.text.erb： 嗨 ,
Welcome to the Sample App. Click on the link below to activate your account:
<%= edit_account_activation_url(@user.activation_token, email: @user.email) %>
user.rb:
class User < ActiveRecord::Base
attr_accessor :remember_token, :activation_token
before_save :downcase_email
before_create :create_activation_digest
validates :name, presence: true, length: { maximum: 50 }
VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i
validates :email, presence: true, length: { maximum: 255 },
format: { with: VALID_EMAIL_REGEX },
uniqueness: { case_sensitive: false }
has_secure_password
validates :password, length: { minimum: 6 }, allow_blank: true
# Returns the hash digest of the given string.
def User.digest(string)
cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
BCrypt::Engine.cost
BCrypt::Password.create(string, cost: cost)
end
# Returns a random token
def User.new_token
SecureRandom.urlsafe_base64
end
# Remembers a user in the database for use in persistent sessions
def remember
self.remember_token = User.new_token
update_attribute(:remember_digest, User.digest(remember_token))
end
# Returns true if the given token matches the digest.
def authenticated?(remember_token)
return false if remember_digest.nil?
BCrypt::Password.new(remember_digest).is_password?(remember_token)
end
# Forgets a user.
def forget
update_attribute(:remember_digest, nil)
end
private
# Converts email to all lower-case.
def downcase_email
self.email = email.downcase
end
# Creates and assigns the activation token and digest.
def create_activation_digest
self.activation_token = User.new_token
self.activation_digest = User.digest(activation_token)
end
end
【问题讨论】：
标签： ruby-on-rails ruby railstutorial.org