一个迭代开发中的网站难免存在bug，出bug的时候客户体验就很不好了，为解决此问题，可以在class error产生的时候，触发跳转到统一提示页面，并给开发人员发邮件报错误信息，提高测试能力和用户体验。以下是核心方法；在ApplicationController中添加如下代码，不同rails版本的class error略有变化。
AR_ERROR_CLASSES = [ActiveRecord::RecordNotFound, ActiveRecord::StatementInvalid]
ERROR_CLASSES = [NameError, NoMethodError, RuntimeError,
ActionView::TemplateError,
ActiveRecord::StaleObjectError, ActionController::RoutingError,
ActionController::UnknownController, AbstractController::ActionNotFound,
ActionController::MethodNotAllowed, ActionController::InvalidAuthenticityToken]
ACCESS_DENIED_CLASSES = [CanCan::AccessDenied]
if Rails.env.production?
rescue_from *AR_ERROR_CLASSES, :with => :render_ar_error
rescue_from *ERROR_CLASSES, :with => :render_error
rescue_from *ACCESS_DENIED_CLASSES, :with => :render_access_denied
end
#called by last route matching unmatched routes. Raises RoutingError which will be rescued from in the same way as other exceptions.
#备注rails3.1后ActionController::RoutingError在routes.rb中最后加如下代码才能catch了。
#rails3下：match '*unmatched_route', :to => 'application#raise_not_found!'
#rails4下：get '*unmatched_route', :to => 'application#raise_not_found!'
def raise_not_found!
raise ActionController::RoutingError.new("No route matches #{params[:unmatched_route]}")
end
def render_ar_error(exception)
case exception
when *AR_ERROR_CLASSES then exception_class = exception.class.to_s
else exception_class = 'Exception'
end
send_error_email(exception, exception_class)
end
def render_error(exception)
case exception
when *ERROR_CLASSES then exception_class = exception.class.to_s
else exception_class = 'Exception'
end
send_error_email(exception, exception_class)
end
def render_access_denied(exception)
case exception
when *ACCESS_DENIED_CLASSES then exception_class = exception.class.to_s
else exception_class = "Exception"
end
send_error_email(exception, exception_class)
end