Leon's notes

Paypal on Rails, gotchas and tricks

With the help of Activemerchant, integrate Paypal into Rails is really easy, yet there are some gotchas you should be aware of.

1. The original ‘_ext-enter’ for ‘cmd’ is deprecated
2. If you are to submit multiple line items, the ‘cmd’ value must be ‘_cart’, then you can use item_name_x/quantity_x/amount_x as the line items details
3. The built in helper in Activemerchant do not provide the multiple line mapping, I’ved add one myself, the line_items method.
   then you can use it in your view like 

   - service.line_items line_items

4. The shipping cost to whole cart should be set in ‘handling_cart’, instead of ‘shipping’ as suggested in Paypal’s document, this is really bad.

See the comments you can understand how the customized helper works

# We changed this paypal helper provided by activemerchant because:
# 
# 1) change the initializer to meet our need, for example, 
#   to submit mulitple items, the 'cmd' value should be '_cart',
#   see here: https://www.x.com/thread/43442
#   and here: https://www.x.com/docs/DOC-1340
#   the original '_ext-enter' for 'cmd' is deprecated
# 
# 2) add the line_items method to prepare details for each line item
# 
# 3) accroding to https://www.x.com/thread/39507
#   if you want to pass shpping cost for the whole cart, 
#   you should set up the 'handling_cart' instead of 'shipping' as documented
#   mapping :shipping, 'handling_cart'

module ActiveMerchant #:nodoc:
  module Billing #:nodoc:
    module Integrations #:nodoc:
      module Paypal
        class Helper < ActiveMerchant::Billing::Integrations::Helper
          def initialize(order, account, options = {})
            super
            # indecate we are using thirdparty shopping cart
            add_field('cmd', '_cart')
            add_field('upload', '1')


            add_field('no_shipping', '1')
            add_field('no_note', '1')
            add_field('charset', 'utf-8')
            add_field('address_override', '0')
            add_field('bn', application_id.to_s.slice(0,32)) unless application_id.blank?
          end
          
          # pass the shipping cost for whole cart
          mapping :shipping, 'handling_cart'

          # mapping header image
          mapping :cpp_header_image, 'cpp_header_image'

          # add line item details, note the amount_x 
          # should be price instead of line total   
          def line_items(items = [])
            items.each_with_index do |line, index|
              add_field("item_name_#{index+1}", line.item.item_name)
              add_field("amount_#{index+1}", line.price.value_without_unit)
              add_field("quantity_#{index+1}", line.quantity)
            end
          end          

        end
      end
    end
  end
end

Also, you need to create your own payment_service_for( I named it paypal_payment_service_for) to support encrypt data before sending to paypal, because the built in payment_service_for in Activemerchant does not suppor that

require_library_or_gem 'action_pack'

module ActiveMerchant #:nodoc:
  module Billing #:nodoc:
    module Integrations #:nodoc:
      module ActionViewHelper
        def paypal_payment_service_for(order, account, options = {}, &proc)
          raise ArgumentError, "Missing block" unless block_given?

          integration_module = ActiveMerchant::Billing::Integrations.const_get(options.delete(:service).to_s.camelize)

          encrypt = options.delete(:encrypt)

          result = []
          result << form_tag(integration_module.service_url, options.delete(:html) || {})

          service_class = integration_module.const_get('Helper')
          service = service_class.new(order, account, options)

          result << capture(service, &proc)

          if encrypt
            paypal_params = { :cert_id => cert_id }
            service.form_fields.each do |field, value|
              paypal_params.merge!(field => value)
            end

            result << hidden_field_tag(:cmd, "_s_xclick")
            result << "\n"
            result << hidden_field_tag(:encrypted, encrypt_for_paypal(paypal_params))
          else
            service.form_fields.each do |field, value|
              result << hidden_field_tag(field, value)
            end
          end

          result << ''
          result= result.join("\n")

          concat(result.respond_to?(:html_safe) ? result.html_safe : result)
          nil
        end

        # encrypt values
        def encrypt_for_paypal(values)
          unless Settings.payment.paypal.test_mode
            app_cert_pem = File.read("#{Rails.root}/config/paypal/paypal-pubcert.pem")
            app_key_pem = File.read("#{Rails.root}/config/paypal/paypal-prvkey.pem")
            paypal_cert_pem = File.read("#{Rails.root}/config/paypal/paypal-cert.pem")
          else
            app_cert_pem = File.read("#{Rails.root}/config/paypal/paypal-sandbox-pubcert.pem")
            app_key_pem = File.read("#{Rails.root}/config/paypal/paypal-sandbox-prvkey.pem")
            paypal_cert_pem = File.read("#{Rails.root}/config/paypal/paypal-sandbox-cert.pem")
          end

          signed = OpenSSL::PKCS7::sign(OpenSSL::X509::Certificate.new(app_cert_pem), OpenSSL::PKey::RSA.new(app_key_pem, ''), values.map { |k, v| "#{k}=#{v}" }.join("\n"), [], OpenSSL::PKCS7::BINARY)
          OpenSSL::PKCS7::encrypt([OpenSSL::X509::Certificate.new(paypal_cert_pem)], signed.to_der, OpenSSL::Cipher::Cipher::new("DES3"), OpenSSL::PKCS7::BINARY).to_s.gsub("\n", "")
        end

        def cert_id
          Settings.payment.paypal.certificate_id
        end
      end
    end
  end
end

Test basic auth with Cucumber

The senario

Scenario: admin dashboard
  Given I perform HTTP authentication as "admin/secret"
    And I am on "/admin"
  Then I should see "Dashboard"

The step

When /^I perform HTTP authentication as "([^\"]*)\/([^\"]*)"$/ do |name, password|
  if page.driver.respond_to?(:basic_auth)
    page.driver.basic_auth(name, password)
  elsif page.driver.respond_to?(:basic_authorize)
    page.driver.basic_authorize(name, password)
  elsif page.driver.respond_to?(:browser) && page.driver.browser.respond_to?(:basic_authorize)
    page.driver.browser.basic_authorize(name, password)
  else
    raise "I don't know how to log in!"
  end
end

from the discussion here:
http://stackoverflow.com/questions/4329985/http-basic-auth-for-capybara

When using selenium driver, according to their wiki

How do I use Selenium to login to sites that require HTTP basic authentication (where the browser makes a modal dialog asking for credentials)?

Use a username and password in the URL, as described in RFC 1738:

open  http://myusername:myuserpassword@myexample.com/blah/blah/blah

Note that on Internet Explorer this won’t work, since Microsoft has disabled usernames/passwords in URLs in IE. However, you can add that functionality back in by modifying your registry, as described in the linked KB article. Set an “iexplore.exe” DWORD to 0 in HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_HTTP_USERNAME_PASSWORD_DISABLE.

If you don’t want to modify the registry yourself, you can always just use Selenium Remote Control, which automatically sets that that registry key for you as of version 0.9.2.

Also the discussion on github:

iast opened this issue January 02, 2011

HTTP Basic Authentication for Selenium driver

No milestone

No one is assigned

Hi, I’m using Cucumber+Capybara+Selenium to test the app that relies on HTTP Basic Authentication. There is a way to use this kind of auth by calling page.driver.basic_authorize(user, pass) method.

But when I mark the Scenario with @javascript tag (enabling Selenium driver) I get an error:
undefined method `basic_authorize’ for #Capybara::Driver::Selenium:0x000000041ea880 (NoMethodError)

 jnicklas commented

January 09, 2011

You’re accessing a private API and calling through to a method which is specific to the rack-test driver. Selenium doesn’t support basic authentication other than through the URL afaik, which is why we don’t have an API for it in Capybara in the first place.

 iast commented

January 12, 2011

It’s a pity. It would be nice to have a cross-driver way of using basic auth.

But, anyway, I solved the problem in my case by using URL to identify current user and session to persist current user between requests (when Selenium is active only).

Thanks for the reply.

The only way would be something like “http://myusername:myuserpassword@myexample.com/blah/blah/blah”

iTerm2

早上在twitter看到：

“robinlu iTerm2 发布1.0了，最近一直在用。我比较喜欢的功能主要是可分割窗口，窗口内容可搜索。”

下载试了一下，非常惊喜，可分割窗口和搜索功能确实很实用，感谢robinlu的推荐。

more: http://www.iterm2.com/

Update(2011-07-16): iTem2 到行首和行尾的快捷键是 fn + 左右方向键，和terminal中默认的fn + shift + 左右方向键不同。