paypal IPN and PDT 2

       当支付模式为快速支付（按钮）时，IPN 和PDT都会起作用， 当以Rest Api方式创建支付时， PDT是无效的，它应该是针对网站的，IPN依然起作用。调用Rest Api 付款的步骤是这样的：

1. 注册paypal账号， 升级为高级或者企业账号;

2. 登录开发者中心后台，注册app;

3. 获取Client ID, Secret;

4. 设置ipn通知地址（profile里面设置）;

5. 获取paypal SDK， 在sandbox环境测试, 支付返回的url是在调用代码里面设置的；

POST /v1/payments/payment

POST /v1/payments/payment/<Payment-Id>/execute

主要是这两个APi

6. 替换代码sandbox为正式url,上线。

需要注意的问题：

1.如果卖家退款， 资金会立刻结算，并向paypal支付一定的手续费，程序会收到ipn通知；

2.如果买家提出争议，争议类型是未经授权的交易时，资金会立刻冻结，程序会收到ipn通知；

3.如果买家提出争议，争议类型不是未经授权的交易时，资金会立刻冻结，程序不会收到ipn通知；

4. 买家和卖家的唯一交易号是完全不一致的;

5.买家和卖家的发票号（账单号）是一致的;

6.支付返回的url所在的程序，收到的数据不可信， 可以把一切本地的逻辑放在处理ipn的程序里面进行。ipn消息不是实时的，差不多秒级的延迟。

用户支付完成时，返回的url会收到如下请求数据：

  'success' => 'true',
  'paymentId' => 'PAY-1BV5911839643144YKSCUA7Q',
  'token' => 'EC-8684120785130974D',
  'PayerID' => 'JARYJK2TES6C6',

调用execute接口返回：

{    "id": "PAY-1BV5911839643144YKSCUA7Q",    "create_time": "2014-12-08T06:09:02Z",    "update_time": "2014-12-08T06:10:51Z",    "state": "approved",    "intent": "sale",    "payer": {        "payment_method": "paypal",        "payer_info": {            "email": "[e-mail]",            "first_name": "Test",            "last_name": "Buyer",            "payer_id": "JARYJK2TES6C6",            "shipping_address": {                "line1": "NO 1 Nan Jin Road",                "city": "Shanghai",                "state": "Shanghai",                "postal_code": "200000",                "country_code": "CN",                "recipient_name": "Buyer Test"            }        }    },    "transactions": [        {            "amount": {                "total": "20.00",                "currency": "USD",                "details": {                    "subtotal": "17.50",                    "tax": "1.30",                    "shipping": "1.20"                }            },            "description": "Payment description",            "item_list": {                "items": [                    {                        "name": "Ground Coffee 40 oz",                        "price": "7.50",                        "currency": "USD",                        "quantity": "1"                    },                    {                        "name": "Granola bars",                        "price": "2.00",                        "currency": "USD",                        "quantity": "5"                    }                ],                "shipping_address": {                    "recipient_name": "Buyer Test",                    "line1": "NO 1 Nan Jin Road",                    "city": "Shanghai",                    "state": "Shanghai",                    "postal_code": "200000",                    "country_code": "CN"                }            },            "related_resources": [                {                    "sale": {                        "id": "74V52932AB811673C",                        "create_time": "2014-12-08T06:09:02Z",                        "update_time": "2014-12-08T06:10:51Z",                        "amount": {                            "total": "20.00",                            "currency": "USD"                        },                        "payment_mode": "INSTANT_TRANSFER",                        "state": "completed",                        "protection_eligibility": "ELIGIBLE",                        "protection_eligibility_type": "ITEM_NOT_RECEIVED_ELIGIBLE,UNAUTHORIZED_PAYMENT_ELIGIBLE",                        "parent_payment": "PAY-1BV5911839643144YKSCUA7Q",                        "links": [                            {                                "href": "https://api.sandbox.paypal.com/v1/payments/sale/74V52932AB811673C",                                "rel": "self",                                "method": "GET"                            },                            {                                "href": "https://api.sandbox.paypal.com/v1/payments/sale/74V52932AB811673C/refund",                                "rel": "refund",                                "method": "POST"                            },                            {                                "href": "https://api.sandbox.paypal.com/v1/payments/payment/PAY-1BV5911839643144YKSCUA7Q",                                "rel": "parent_payment",                                "method": "GET"                            }                        ]                    }                }            ]        }    ],    "links": [        {            "href": "https://api.sandbox.paypal.com/v1/payments/payment/PAY-1BV5911839643144YKSCUA7Q",            "rel": "self",            "method": "GET"        }    ]}

同时服务器会收到ipn消息， 类似：

array (  'act' => 'ipn',  'mc_gross' => '20.00',  'invoice' => '548531d624f59',  'protection_eligibility' => 'Eligible',  'address_status' => 'unconfirmed',  'item_number1' => '',  'tax' => '1.30',  'item_number2' => '',  'payer_id' => 'JARYJK2TES6C6',  'address_street' => 'NO 1 Nan Jin Road',  'payment_date' => '21:04:35 Dec 07, 2014 PST',  'payment_status' => 'Completed',  'charset' => 'gb2312',  'address_zip' => '200000',  'mc_shipping' => '1.20',  'mc_handling' => '0.00',  'first_name' => 'Test',  'mc_fee' => '0.98',  'address_country_code' => 'CN',  'address_name' => 'Buyer Test',  'notify_version' => '3.8',  'custom' => '',  'payer_status' => 'unverified',  'address_country' => 'China',  'num_cart_items' => '2',  'mc_handling1' => '0.00',  'mc_handling2' => '0.00',  'address_city' => 'Shanghai',  'verify_sign' => 'AomRS5l2W2xlt2An.GaSrAzpCl-NACIvh3Pz0HtrSBZzfcIeqDPGrXSk',  'payer_email' => '[e-mail]',  'mc_shipping1' => '0.00',  'mc_shipping2' => '0.00',  'tax1' => '0.00',  'tax2' => '0.00',  'txn_id' => '5CS19517SJ894934R',  'payment_type' => 'instant',  'last_name' => 'Buyer',  'address_state' => 'Shanghai',  'item_name1' => 'Ground Coffee 40 oz',  'receiver_email' => '[e-mail]',  'item_name2' => 'Granola bars',  'payment_fee' => '0.98',  'quantity1' => '1',  'quantity2' => '5',  'receiver_id' => '937CP9PSMDS2A',  'txn_type' => 'cart',  'mc_gross_1' => '7.50',  'mc_currency' => 'USD',  'mc_gross_2' => '10.00',  'residence_country' => 'CN',  'test_ipn' => '1',  'transaction_subject' => '',  'payment_gross' => '20.00',  'ipn_track_id' => 'a9059421a1dd7',)2014-12-08 13:04:35

卖家退款收到的ipn：

array (  'act' => 'ipn',  'mc_gross' => '-55.90',  'protection_eligibility' => 'Eligible',  'payer_id' => 'JARYJK2TES6C6',  'address_street' => 'NO 1 Nan Jin Road',  'payment_date' => '18:17:29 Dec 07, 2014 PST',  'payment_status' => 'Refunded',  'charset' => 'gb2312',  'address_zip' => '200000',  'first_name' => 'Test',  'mc_fee' => '-1.90',  'address_country_code' => 'CN',  'address_name' => 'Buyer Test',  'notify_version' => '3.8',  'reason_code' => 'refund',  'custom' => '',  'business' => '[e-mail]',  'address_country' => 'China',  'address_city' => 'Shanghai',  'verify_sign' => 'AIkKNboJiyuxWLOHUlzTd3lpqCSxA1j2G80g.Gf68usTx7dykHwVOx4g',  'payer_email' => '[e-mail]',  'parent_txn_id' => '78V79646KB938951Y',  'txn_id' => '03C86087BS569332H',  'payment_type' => 'instant',  'btn_id' => '3042078',  'last_name' => 'Buyer',  'address_state' => 'Shanghai',  'receiver_email' => '[e-mail]',  'payment_fee' => '-1.90',  'shipping_discount' => '0.00',  'receiver_id' => '2XP27KEMUVN8A',  'insurance_amount' => '0.00',  'item_name' => 'sandbox_item111',  'discount' => '0.00',  'mc_currency' => 'USD',  'item_number' => '',  'residence_country' => 'CN',  'test_ipn' => '1',  'handling_amount' => '0.00',  'shipping_method' => 'Default',  'transaction_subject' => '',  'payment_gross' => '-55.90',  'shipping' => '10.00',  'ipn_track_id' => '2d16876d72c70',)2014-12-08 10:17:27

资金冻结时候收到的ipn：

array (  'act' => 'ipn',  'mc_gross' => '-19.02',  'invoice' => '548541570184f',  'protection_eligibility' => 'Eligible',  'item_number1' => '',  'item_number2' => '',  'payer_id' => 'JARYJK2TES6C6',  'address_street' => 'NO 1 Nan Jin Road',  'payment_date' => '22:23:36 Dec 07, 2014 PST',  'payment_status' => 'Reversed',  'charset' => 'gb2312',  'address_zip' => '200000',  'mc_shipping' => '1.20',  'mc_handling' => '0.00',  'first_name' => 'Test',  'mc_fee' => '-0.98',  'address_country_code' => 'CN',  'address_name' => 'Buyer Test',  'notify_version' => '3.8',  'reason_code' => 'unauthorized_claim',  'custom' => '',  'address_country' => 'China',  'mc_handling1' => '0.00',  'mc_handling2' => '0.00',  'address_city' => 'Shanghai',  'verify_sign' => 'A.7n6Acd75CB8FdbeZyRGF.BoVPlArI2BzuxGNUFbCI-qvgcHJe4LgLp',  'payer_email' => '[e-mail]',  'mc_shipping1' => '0.00',  'mc_shipping2' => '0.00',  'tax1' => '0.00',  'tax2' => '0.00',  'parent_txn_id' => '74V52932AB811673C',  'memo' => '14.13',  'txn_id' => '2Y80904055783821A',  'payment_type' => 'instant',  'last_name' => 'Buyer',  'address_state' => 'Shanghai',  'item_name1' => 'Ground Coffee 40 oz',  'receiver_email' => '[e-mail]',  'item_name2' => 'Granola bars',  'payment_fee' => '-0.98',  'quantity1' => '1',  'quantity2' => '5',  'receiver_id' => '937CP9PSMDS2A',  'mc_gross_1' => '7.50',  'mc_currency' => 'USD',  'mc_gross_2' => '10.00',  'residence_country' => 'CN',  'test_ipn' => '1',  'transaction_subject' => '',  'payment_gross' => '-19.02',  'ipn_track_id' => '5df4cee26f6d3',)2014-12-08 14:23:33