为什么我不能在User实例方法中使用root_path？（未定义的局部变量或方法）

Question

我需要为用户调用方法，该方法具有电子邮件参数。 这是在PayPal支付的功能，我正在设置返回网址和取消网址。

这是我的方法，在user.rb中：

   def pay email
require 'httpclient'
require 'xmlsimple'
clnt = HTTPClient.new
credentials = {
    'USER' => 'payer_1342623102_biz_api1.gmail.com',
   'PWD' => '1342623141',
   'SIGNATURE' => 'Ay2zwWYEoiRoHTTVv365EK8U1lNzAESedJw09MPnj0SEIENMKd6jvnKL '
 }

header =  {"X-PAYPAL-SECURITY-USERID" => "payer_1342623102_biz_api1.gmail.com",
               "X-PAYPAL-SECURITY-PASSWORD" => "1342623141",
               "X-PAYPAL-SECURITY-SIGNATURE" =>"Ay2zwWYEoiRoHTTVv365EK8U1lNzAESedJw09MPnj0SEIENMKd6jvnKL ",
               "X-PAYPAL-REQUEST-DATA-FORMAT" => "NV",
               "X-PAYPAL-RESPONSE-DATA-FORMAT" => "XML",
               "X-PAYPAL-APPLICATION-ID" =>  "APP-80W284485P519543T"
                }
data = {"actionType" => "PAY",
           "receiverList.receiver(0).email"=> email,
           "receiverList.receiver(0).amount" => "10",
           "currencyCode" => "USD",
           "cancelUrl" => root_path,
           "returnUrl" => root_path,
           "requestEnvelope.errorLanguage" => "en_US"}
uri = "https://svcs.sandbox.paypal.com/AdaptivePayments/Pay"
res = clnt.post(uri, data, header)
@xml = XmlSimple.xml_in(res.content)
payKey = @xml["payKey"].to_s()
payKey = payKey.tr("[]", "")
payKey = payKey[1..20]
redirect_to "https://sandbox.paypal.com/webscr?cmd=_ap-payment&paykey=#{payKey}"
 end

我收到错误：

      undefined local variable or method `root_path'

为什么我不能使用这种方法？ 为什么我不能使用redirect_to？

Answer 1

我不认为root_path或root_url默认在模型类中可用。 这是设计使然，因为您的模型不应该知道控制器/视图/会话类操作。 您可以通过将其包含在模型中来访问root_url：

include Rails.application.routes.url_helpers

更好的解决方案是将此信息传递给order.pay方法。