为什么我的 PayPal IPN 响应中的自定义参数为空？

Why is the custom parameter in my PayPal IPN response empty?

在我的 PayPal IPN 响应中，自定义参数为空。

我尝试了以下 post 数据：

METHOD=SetExpressCheckout&VERSION=121.0&USER=mark.vanhaaren1987-facilitator_api1.gmail.com&PWD=1411391015&SIGNATURE=AiPC9BjkCyDFQXbSkoZcgqH3hpacAa1vFAMOEAO1ZachEpl5mX2RGSRb&RETURNURL=https%3a%2f%2fdev-api.wedepa.com%2freturn%2freturn%3fwedepaid%3d32-303-true-e3c7a8f25359d0ad625c4389102aa0cabdfb172e&CANCELURL=https%3a%2f%2fdev-api.wedepa.com%2freturn%2freturn%3fwedepaid%3d32-303-true-e3c7a8f25359d0ad625c4389102aa0cabdfb172e&REQCONFIRMSHIPPING=0&LOCALECODE=&EMAIL=pending_accepted%2540klarna.com&LANDINGPAGE=Login&PAYMENTREQUEST_0_SHIPTONAME=Testperson-nl+Approved&PAYMENTREQUEST_0_SHIPTOSTREET=Neherkade+1XI&PAYMENTREQUEST_0_SHIPTOSTREET2=&PAYMENTREQUEST_0_SHIPTOCITY=Gravenhage&PAYMENTREQUEST_0_SHIPTOSTATE=&PAYMENTREQUEST_0_SHIPTOZIP=2521VA&PAYMENTREQUEST_0_SHIPTOCOUNTRYCODE=NL&PAYMENTREQUEST_0_SHIPTOPHONENUM=0612345678&PAYMENTREQUEST_0_AMT=0.56&PAYMENTREQUEST_0_CURRENCYCODE=EUR&PAYMENTREQUEST_0_ITEMAMT=0.56&PAYMENTREQUEST_0_DESC=145000610&PAYMENTREQUEST_0_CUSTOM=303&PAYMENTREQUEST_0_INVNUM=145000610&PAYMENTREQUEST_0_PAYMENTACTION=Sale&PAYMENTREQUEST_0_PAYMENTREQUESTID=303

和

METHOD=SetExpressCheckout&VERSION=121.0&USER=mark.vanhaaren1987-facilitator_api1.gmail.com&PWD=1411391015&SIGNATURE=AiPC9BjkCyDFQXbSkoZcgqH3hpacAa1vFAMOEAO1ZachEpl5mX2RGSRb&RETURNURL=https%3a%2f%2fdev-api.wedepa.com%2freturn%2freturn%3fwedepaid%3d32-303-true-e3c7a8f25359d0ad625c4389102aa0cabdfb172e&CANCELURL=https%3a%2f%2fdev-api.wedepa.com%2freturn%2freturn%3fwedepaid%3d32-303-true-e3c7a8f25359d0ad625c4389102aa0cabdfb172e&REQCONFIRMSHIPPING=0&LOCALECODE=&EMAIL=pending_accepted%2540klarna.com&LANDINGPAGE=Login&PAYMENTREQUEST_0_SHIPTONAME=Testperson-nl+Approved&PAYMENTREQUEST_0_SHIPTOSTREET=Neherkade+1XI&PAYMENTREQUEST_0_SHIPTOSTREET2=&PAYMENTREQUEST_0_SHIPTOCITY=Gravenhage&PAYMENTREQUEST_0_SHIPTOSTATE=&PAYMENTREQUEST_0_SHIPTOZIP=2521VA&PAYMENTREQUEST_0_SHIPTOCOUNTRYCODE=NL&PAYMENTREQUEST_0_SHIPTOPHONENUM=0612345678&PAYMENTREQUEST_0_AMT=0.56&PAYMENTREQUEST_0_CURRENCYCODE=EUR&PAYMENTREQUEST_0_ITEMAMT=0.56&PAYMENTREQUEST_0_DESC=145000610&CUSTOM=303&PAYMENTREQUEST_0_INVNUM=145000610&PAYMENTREQUEST_0_PAYMENTACTION=Sale&PAYMENTREQUEST_0_PAYMENTREQUESTID=303

但是在两个 post 中，自定义参数在 IPN 数据中都是空的：

mc_gross=0.56&protection_eligibility=Eligible&address_status=unconfirmed&payer_id=WVANQ6YXN3Z44&tax=0.00&address_street=Neherkade+1XI&payment_date=02%3A25%3A07+Apr+05%2C+2015+PDT&payment_status=Completed&charset=windows-1252&address_zip=2521VA&first_name=SandboxTest&mc_fee=0.37&address_country_code=NL&address_name=Testperson-nl+Approved&notify_version=3.8&custom=&payer_status=verified&address_country=Netherlands&address_city=Gravenhage&quantity=1&verify_sign=AWOaXag9big7U1TLyuUBdjQukr3NAId64fyHo.KuCCvftrNBM1o3xHVd&payer_email=mark%40mvhaaren.com&txn_id=7XS68223YK9539538&payment_type=instant&last_name=Account&address_state=&receiver_email=mark.vanhaaren1987-facilitator%40gmail.com&payment_fee=&receiver_id=A3TRBFWRTUBBL&txn_type=express_checkout&item_name=&mc_currency=EUR&item_number=&residence_country=NL&test_ipn=1&handling_amount=0.00&transaction_subject=&payment_gross=&shipping=0.00&ipn_track_id=7f79e2488253

有人能看出我做错了什么吗？

PAYMENTREQUEST_0_CUSTOM 参数需要在您的 DoExpressCheckoutPayment 调用中，而不是在您的 SetExpressCheckout 调用中。