Question

当我的Rails（3.2.13）应用启动时，我想从数据库加载一些配置设置：

class MyApp < Rails::Application
  #...normal config here...

  config.action_mailer.raise_delivery_errors = true
  config.action_mailer.delivery_method       = :smtp
  config.action_mailer.smtp_settings         = {
    :address              => SystemSetting.system_smtp_host,
    :port                 => SystemSetting.system_smtp_port,
    :user_name            => SystemSetting.system_smtp_username,
    :password             => SystemSetting.system_smtp_password,
    :authentication       => SystemSetting.system_smtp_authentication,
    :enable_starttls_auto => SystemSetting.system_smtp_enable_starttls_auto }
end

但似乎此时尚未读取数据库配置。我收到一个错误：

ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished)

我怎样才能做到这一点？要么让Rails首先初始化数据库配置，要么......其他什么？

Answer 1

关于实践：做这样的事情可能会有问题，因为您的应用程序依赖于您的数据库已满，而实际上它应该支持空数据库。我可以想到的两个例子是当您尝试从头开始创建数据库（例如rake db：setup）或测试环境时。

但是，如果没有其他选择：我会将邮件程序初始化移动到您的system_setting.rb或初始化程序（保证您有连接）。

<强>配置/初始化/ load_system_settings.rb

MyApp::Application.config.action_mailer.raise_delivery_errors = true
MyApp::Application.config.action_mailer.delivery_method       = :smtp
MyApp::Application.config.action_mailer.smtp_settings         = {
  :address              => SystemSetting.system_smtp_host,
  :port                 => SystemSetting.system_smtp_port,
  :user_name            => SystemSetting.system_smtp_username,
  :password             => SystemSetting.system_smtp_password,
  :authentication       => SystemSetting.system_smtp_authentication,
  :enable_starttls_auto => SystemSetting.system_smtp_enable_starttls_auto
}

Answer 2

手动连接并加载数据库中的值。

class Application < Rails::Application

  # Set your app path
  app_base = 'MY_APPLICATION_PATH' 

  # Load db configs
  db_yml = YAML.load_file("#{app_base}/config/database.yml")["production"]

  # Establish db connection
  ActiveRecord::Base.establish_connection(:adapter=>db_yml['adapter'], :database=>db_yml['database'], :username=>db_yml['username'], :password=>db_yml['password']) 

  # load model if not 
  require "#{app_base}/app/model/system_setting.rb" unless defined?('SystemSetting')

  #...normal config here...

  config.action_mailer.raise_delivery_errors           = true
  config.action_mailer.delivery_method                 = :smtp
  config.action_mailer.smtp_settings                   = {
    :address                                          => SystemSetting.system_smtp_host,
    :port                                             => SystemSetting.system_smtp_port,
    :user_name                                        => SystemSetting.system_smtp_username,
    :password                                         => SystemSetting.system_smtp_password,
    :authentication                                   => SystemSetting.system_smtp_authentication,
    :enable_starttls_auto                             => SystemSetting.system_smtp_enable_starttls_auto }

  #close sql connection after loaded 
   ActiveRecord::Base.connection.close
end

从数据库加载rails app config

2 个答案: