Paypal adaptive payment API call with C# .NET? Preferably with WebServices

Question

Okay I might be entirely off track now but here goes:

Our "webshop" offers two functions, buying a specific product and selling it back to us. Back-end handles if the user can sell or not.

I've decided to use Paypal's adaptive payments for this one as it seems the way to go doing these kinds of transactions. I've never implemented any kind of shop so I'm totally green with this one. I only recently learned ASP.NET and have mainly developed games before moving to this kind of development. HTTP is still some level of magic to me hehe..

I might be confused but I think paypal offers a webservice with their adaptive payment API. My humble request: A nice soul who wants to share an example of implementing an adaptive payment API call with C# .NET. If they don't offer it as a webservice I'll probably find it as a custom .dll or something.

Any tips and examples are highly appreciated! Thanks for reading

Answer 1

https://www.x.com/docs/DOC-1414

and

https://www.x.com/community/ppx/code_samples

This is their xml api. I have not gotten their webservices to work using the auto-generated proxies in vs.net. Also keep in mind you'll have to declare constants or variables for the api info, buyer, seller, etc.

        // API endpoint for the Refund call in the Sandbox
        string sAPIEndpoint = "https://svcs.sandbox.paypal.com/AdaptivePayments/Pay";

        // Version that you are coding against
        string sVersion = "1.1.0";

        // Error Langugage
        string sErrorLangugage = "en_US";

        // Detail Level
        string sDetailLevel = "ReturnAll";

        // Request Data Binding
        string sRequestDataBinding = "XML";

        // Response Data Binding
        string sResponseDataBinding = "XML";

        // Application ID
        string sAppID = "APP-80W284485P519543T";

        // other clientDetails fields
        string sIpAddress = "255.255.255.255";
        string sPartnerName = "MyCompanyName";
        string sDeviceID = "255.255.255.255";

        // Currency Code
        string sCurrencyCode = "USD";

        // Action Type
        string sActionType = "PAY";

        // ReturnURL and CancelURL used for approval flow
        string sReturnURL = "https://MyReturnURL";
        string sCancelURL = "https://MyCancelURL";

        // who pays the fees
        string sFeesPayer = "EACHRECEIVER";

        // memo field
        string sMemo = "testing my first pay call";

        // transaction amount
        string sAmount = "5";

        // supply your own sandbox accounts for receiver and sender


        string sTrackingID = System.Guid.NewGuid().ToString();

        // construct the XML request string
        StringBuilder sRequest = new StringBuilder("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
        sRequest.Append("<PayRequest xmlns:ns2=\"http://svcs.paypal.com/types/ap\"&gt;");
        // requestEnvelope fields
        sRequest.Append("<requestEnvelope><errorLanguage>");
        sRequest.Append(sErrorLangugage);
        sRequest.Append("</errorLanguage><detailLevel>");
        sRequest.Append(sDetailLevel);
        sRequest.Append("</detailLevel></requestEnvelope>");
        // clientDetails fields
        sRequest.Append("<clientDetails><applicationId>");
        sRequest.Append(sAppID);
        sRequest.Append("</applicationId><deviceId>");
        sRequest.Append(sDeviceID);
        sRequest.Append("</deviceId><ipAddress>");
        sRequest.Append(sIpAddress);
        sRequest.Append("</ipAddress><partnerName>");
        sRequest.Append(sPartnerName);
        sRequest.Append("</partnerName></clientDetails>");
        // request specific data fields
        sRequest.Append("<actionType>");
        sRequest.Append(sActionType);
        sRequest.Append("</actionType><cancelUrl>");
        sRequest.Append(sCancelURL);
        sRequest.Append("</cancelUrl><returnUrl>");
        sRequest.Append(sReturnURL);
        sRequest.Append("</returnUrl><currencyCode>");
        sRequest.Append(sCurrencyCode);
        sRequest.Append("</currencyCode><feesPayer>");
        sRequest.Append(sFeesPayer);
        sRequest.Append("</feesPayer><memo>");
        sRequest.Append(sMemo);
        sRequest.Append("</memo><receiverList><receiver><amount>");
        sRequest.Append(sAmount);
        sRequest.Append("</amount><email>");
        sRequest.Append(Receiver);
        sRequest.Append("</email></receiver></receiverList><senderEmail>");
        sRequest.Append(Sender);
        sRequest.Append("</senderEmail><trackingId>");
        sRequest.Append(sTrackingID);
        sRequest.Append("</trackingId></PayRequest>");


        // get ready to make the call
        HttpWebRequest oPayRequest = (HttpWebRequest)WebRequest.Create(sAPIEndpoint);
        oPayRequest.Method = "POST";
        byte[] array = Encoding.UTF8.GetBytes(sRequest.ToString());
        oPayRequest.ContentLength = array.Length;
        oPayRequest.ContentType = "text/xml;charset=utf-8";
        // set the HTTP Headers
        oPayRequest.Headers.Add("X-PAYPAL-SECURITY-USERID", UserID);
        oPayRequest.Headers.Add("X-PAYPAL-SECURITY-PASSWORD", Pass);
        oPayRequest.Headers.Add("X-PAYPAL-SECURITY-SIGNATURE", Signature);
        oPayRequest.Headers.Add("X-PAYPAL-SERVICE-VERSION", sVersion);
        oPayRequest.Headers.Add("X-PAYPAL-APPLICATION-ID", sAppID);
        oPayRequest.Headers.Add("X-PAYPAL-REQUEST-DATA-FORMAT", sRequestDataBinding);
        oPayRequest.Headers.Add("X-PAYPAL-RESPONSE-DATA-FORMAT", sResponseDataBinding);
        // send the request
        Stream oStream = oPayRequest.GetRequestStream();
        oStream.Write(array, 0, array.Length);
        oStream.Close();
        // get the response
        HttpWebResponse oPayResponse = (HttpWebResponse)oPayRequest.GetResponse();
        StreamReader oStreamReader = new StreamReader(oPayResponse.GetResponseStream());
        string sResponse = oStreamReader.ReadToEnd();
        oStreamReader.Close();