All I need was a simple request to authorise a set of card details, getting back a response to allow the order to either be processed appropriately.
Pulling together with my own code a few different examples online, the Paypal documentation and some advice from their technical support led me to this function - which I'll post in the hope of helping rather than hindering someone else in the same position!
1 private void makePayPalPayment()
2 {
3 //Open log file
4 TextWriter objLogFile;
5 objLogFile = File.AppendText(ConfigurationManager.AppSettings["PaypalLogFilePath"]);
6 try
7 {
8 objLogFile.WriteLine("Paypal request commenced: " + DateTime.Now.ToString());
9
10 //Get details for request
11 // - get paypal endpoint and authorisation details
12 string endPoint = ConfigurationManager.AppSettings["PayPalEndPoint"];
13 string username = ConfigurationManager.AppSettings["PayPalUserName"];
14 string password = ConfigurationManager.AppSettings["PayPalPassword"];
15 string signature = ConfigurationManager.AppSettings["PayPalSignature"];
16 // - get IP of current user
17 string ip = Request.ServerVariables["REMOTE_ADDR"];
18 // - get customer details (from form fields)
19 string cardType = ddlCardType.SelectedItem.Value;
20 string cardNumber = txtCardNumber.Text;
21 string expDate = ddlExpiryDateMonth.SelectedItem.Value + ddlExpiryDateYear.SelectedItem.Value;
22 string securityCode = txtSecurityCode.Text;
23 string firstName = txtFirstName.Text;
24 string lastName = txtLastName.Text;
25 string street = txtStreet.Text;
26 string city = txtCity.Text;
27 string state = txtState.Text;
28 string zip = txtZip.Text;
29 string countryCode = ddlCountry.SelectedItem.Value;
30 // - get order details (hardcoded in this example)
31 decimal orderAmount = 10.0;
32 string currencyCode = "GBP";
33
34 //Build request
35 StringBuilder request = new StringBuilder();
36 request.Append("VERSION=52.0");
37 request.Append("&USER=" + HttpUtility.UrlEncode(username));
38 request.Append("&PWD=" + HttpUtility.UrlEncode(password));
39 request.Append("&SIGNATURE=" + HttpUtility.UrlEncode(signature));
40 request.Append("&METHOD=DoDirectPayment");
41 request.Append("&PAYMENTACTION=Sale");
42 request.Append("&AMT=" + orderAmount.ToString("F"));
43 request.Append("&IPADDRESS=" + HttpUtility.UrlEncode(ip));
44 request.Append("&CREDITCARDTYPE=" + HttpUtility.UrlEncode(cardType));
45 request.Append("&ACCT=" + HttpUtility.UrlEncode(cardNumber));
46 request.Append("&EXPDATE=" + HttpUtility.UrlEncode(expDate));
47 request.Append("&CVV2=" + HttpUtility.UrlEncode(securityCode));
48 request.Append("&FIRSTNAME=" + HttpUtility.UrlEncode(firstName));
49 request.Append("&LASTNAME=" + HttpUtility.UrlEncode(lastName));
50 request.Append("&STREET=" + HttpUtility.UrlEncode(street));
51 request.Append("&CITY=" + HttpUtility.UrlEncode(city));
52 request.Append("&STATE=" + HttpUtility.UrlEncode(state));
53 request.Append("&ZIP=" + HttpUtility.UrlEncode(zip));
54 request.Append("&INVOICEID=" + HttpUtility.UrlEncode(order.ID.ToString()));
55 request.Append("&COUNTRYCODE=" + HttpUtility.UrlEncode(countryCode));
56 request.Append("&CURRENCYCODE=" + HttpUtility.UrlEncode(currencyCode));
57 objLogFile.WriteLine("Request: " + request.ToString());
58
59 //Set up flags for success of operation
60 bool success = false;
61 string errorMessage = "";
62
63 //Make Paypal request
64 HttpWebRequest webRequest = WebRequest.Create(endPoint) as HttpWebRequest;
65 webRequest.Method = "POST";
66 webRequest.ContentType = "application/x-www-form-urlencoded";
67 webRequest.ContentLength = request.Length;
68 StreamWriter writer = new StreamWriter(webRequest.GetRequestStream());
69 writer.Write(request.ToString());
70 writer.Close();
71
72 //Get Paypal response
73 HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
74
75 //Check status
76 if (webRequest.HaveResponse && (webResponse.StatusCode == HttpStatusCode.OK || webResponse.StatusCode == HttpStatusCode.Accepted))
77 {
78 //Response received, so parse into name value pairs for processing
79 StreamReader reader = new StreamReader(webResponse.GetResponseStream());
80 string responseString = reader.ReadToEnd();
81 objLogFile.WriteLine("Response: " + responseString);
82 reader.Close();
83 char[] ampersand = { '&' };
84 char[] equalsign = { '=' };
85 string[] pairs = responseString.Split(ampersand);
86 for (int i = 0; i < pairs.Length; i++)
87 {
88 string[] pair = pairs[i].Split(equalsign);
89 //One pair will be the acknowledgement (ACK) - if this is not set to failure we know the payment has been authorised
90 if (pair[0].ToLower() == "ack" && HttpUtility.UrlDecode(pair[1]).ToLower() != "failure")
91 {
92 success = true;
93 }
94 //One or more messages wil be returned in the case of a failure, so build up list of messages to present to user (or developer :-))
95 if (pair[0].Length > 13 && pair[0].Substring(0,13).ToLower() == "l_longmessage")
96 {
97 errorMessage += "<li>" + HttpUtility.UrlDecode(pair[1]) + "</li>";
98 }
99 }
100 }
101
102 //Display appropriate message to user
103 if (success)
104 {
105 // *** process authorised order ***
106 }
107 else
108 {
109 lblResultMessage.Text = "Sorry, but your payment transaction cannot be proceed. Please review the following messages and try again, or select another payment method.";
110 lblResultMessage.Text += "<ul>" + errorMessage + "</ul>";
111 }
112 }
113 finally
114 {
115 objLogFile.WriteLine("");
116 objLogFile.Close();
117 }
118 }
