M1 Paypal接口改进扩展PayPal Smart Payment Button

PayPal是一家美国公司开发的全球性在线支付系统。
PayPal的服务允许人们在网上进行金融交易，允许个人和企业之间通过电子方式转移资金。
截至2018年，PayPal在202个市场运营，拥有2.44亿活跃注册账户。
PayPal允许客户在全球范围内以25种货币发送、接收和持有资金。
贝宝的智能支付按钮旨在消除尽可能多的结账摩擦。
该按钮出现在checkout工作流中，点击后将立即捕获付款，这有助于客户快速完成付款。
这个扩展为PayPal和非PayPal买家提供了无缝的支付体验。
当客户进入结账流程时，会有针对不同地区的本地化支付方式，可以根据预先输入的地址进行识别。
它为客户提供了一个在弹出窗口中完成支付的直接过程，而不必离开当前页面进行结帐。
客户可以在移动和web浏览器中拥有这种支付体验。
账户和定价
须另开帐户，并须缴付额外费用。
到PayPal官方平台申请官方账号;
帐户类型为业务帐户。
登录PayPal官方平台后，申请PayPal支付商户账号。
PayPal有额外的服务费，请登录PayPal官方网站，在商户仪表盘上查看他们的费率明细。
特性
为客户:
这是一种安全、免费的支付方式，非paypal买家在购买商品时也可以在购物车界面中直接付款。
它将为客户提供无缝的体验，因为如果选择了智能支付按钮，他们不需要离开或从当前页面重定向。
将会有一个弹出窗口让客户直接完成付款。
商家:
多种支付方式同时集成，新的支付方式不需要单独集成。
它是一个智能的、动态的支付网关交付，还提供本地化的支付选项。
如果商家从后端进行退款，退款过程将通过PayPal平台自动进行，并直接在magento系统中进行更新。
安全信息
该扩展使用PayPal官方NVP API，它将是一个弹出窗口，从PayPal完成客户的支付;
客户将在PayPal的弹出窗口中输入支付数据。
它在传输数据时应用PayPal API证书或PayPal API签名。
并且客户的PayPal登录信息不会存储在Magento服务器上，而客户在PayPal中的地址信息将通过PayPal官方NVP API同步到Magento报价地址。
PayPal is a worldwide online payments system developed by an American company. PayPal's services allow people to make financial transactions online by granting the ability to transfer funds electronically between individuals and businesses. As of 2018, PayPal operates in 202 markets and has 244 million active, registered accounts. PayPal allows customers to send, receive, and hold funds in 25 currencies worldwide.  
PayPal's Smart Payment Buttons aims to eliminate as much of the checkout friction as possible. The Button appears in the checkout workflow and will immediately capture the payment after being clicked on, which helps the customer quickly complete their payment.
This extension provides a seamless payment experience for both PayPal and non-PayPal buyers. When customers step into the checkout flow, there will be localized payment methods available for different regions, which can be identified according to the addresses that have been inputted in advance. It provides a direct process for customers to complete the payment within a pop-up window, rather than having to leave the current page for checkout. Customers can have this payment experience in both mobile and web browsers.
Account & PricingA separate account is required and additional fees apply. Go to the PayPal Official Platform to apply for an official account; the account type is business account. Apply for a PayPal Pay Merchant Account after logging into the PayPal Official Platform. There is an additional service fee  for PayPal, please log into the PayPal Official Site, and check their rate details on the merchant dashboard.
FeaturesFor Customers:

• It is a secure and free payment method, and non-PayPal buyers can also pay directly within the shopping cart interface when they purchase goods.

• It will provide a seamless experience for customers, as they do not need to leave or be redirected from the current page if the Smart Payment Button is selected. There will be a pop-up window for customers to finish the payment directly.

For Merchants:

• Multiple payment methods are integrated at once, and a new one does not need to be integrated separately.

• It is an intelligent and dynamic delivery of the payment gateway that provides localized payment options as well.

• If merchants issue a refund from the back end, the drawback process will operate automatically through the PayPal platform and update in the Magento system directly.

Security InformationThis extension uses the PayPal official NVP API, it will be a popup window from PayPal to finish the payment by customers; customers will enter the payment data in the popup window from PayPal. It applies the PayPal API certificate or PayPal API signature when transmitting the data. And the customer's PayPal login information will not be stored Magento server, while customer's address information in the PayPal will be synchronized to Magento Quote Address via the PayPal official NVP API.