How redirect to PayPal screen to approve payment?
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<p>I have action which creating a payment and I need to redirect user to complete Payment.
<p>In Pay API it is said that:

            You must redirect the sender to PayPal to complete the payment

But what is exact url ? Where I should redirect user in development and in production ?
<p>Here is my controller:

    def pay
    require 'httpclient'
    require 'xmlsimple'
    clnt = HTTPClient.new
    header =  {"X-PAYPAL-SECURITY-USERID" => "pro._1342094044_biz_api1.gmail.com",
                   "X-PAYPAL-SECURITY-PASSWORD" => "1342094095",
                   "X-PAYPAL-SECURITY-SIGNATURE" => "AMVxTgrWf6tUTF0Rf0y4QsqTFFAcApSXcqINQj2b2-a5wFhIx3UG87E-",
                   "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"=> "denmed_1342605975_biz@gmail.com",
               "receiverList.receiver(0).amount" => "10",
               "currencyCode" => "USD",
               "cancelUrl" => "http://127.0.0.1:3000",
               "returnUrl" => "http://127.0.0.1:3000",
               "requestEnvelope.errorLanguage" => "en_US"}
    uri = "https://svcs.sandbox.paypal.com/AdaptivePayments/Pay"
    res = clnt.post(uri, data, header)
    "https://www.sandbox.paypal.com/cgi-bin/webscr?" + ???
    //redirect_to WHERE ?
    end