Paypal .net core C# sample

PayPalPaymentCreatedResponse.cs

public class PayPalPaymentCreatedResponse
{
    public string id { get; set; }
    public string intent { get; set; }
    public string state { get; set; }
    public Payer payer { get; set; }
    public Transaction[] transactions { get; set; }
    public DateTime create_time { get; set; }
    public Link[] links { get; set; }

    public class Payer
    {
        public string payment_method { get; set; }
    }

    public class Transaction
    {
        public Amount amount { get; set; }
        public object[] related_resources { get; set; }
    }

    public class Amount
    {
        public string total { get; set; }
        public string currency { get; set; }
    }

    public class Link
    {
        public string href { get; set; }
        public string rel { get; set; }
        public string method { get; set; }
    }
}

PayPalPaymentExecutedResponse.cs

public class PayPalPaymentExecutedResponse
{
    public string id { get; set; }
    public string intent { get; set; }
    public string state { get; set; }
    public string cart { get; set; }
    public Payer payer { get; set; }
    public Transaction[] transactions { get; set; }
    public DateTime create_time { get; set; }
    public Link[] links { get; set; }

    public class Payer
    {
        public string payment_method { get; set; }
        public string status { get; set; }
        public Payer_Info payer_info { get; set; }
    }

    public class Payer_Info
    {
        public string email { get; set; }
        public string first_name { get; set; }
        public string last_name { get; set; }
        public string payer_id { get; set; }
        public Shipping_Address shipping_address { get; set; }
        public string country_code { get; set; }
        public Billing_Address billing_address { get; set; }
    }

    public class Shipping_Address
    {
        public string recipient_name { get; set; }
        public string line1 { get; set; }
        public string city { get; set; }
        public string state { get; set; }
        public string postal_code { get; set; }
        public string country_code { get; set; }
    }

    public class Billing_Address
    {
        public string line1 { get; set; }
        public string line2 { get; set; }
        public string city { get; set; }
        public string state { get; set; }
        public string postal_code { get; set; }
        public string country_code { get; set; }
    }

    public class Transaction
    {
        public Amount amount { get; set; }
        public Payee payee { get; set; }
        public Item_List item_list { get; set; }
        public Related_Resources[] related_resources { get; set; }
    }

    public class Amount
    {
        public string total { get; set; }
        public string currency { get; set; }
        public Details details { get; set; }
    }

    public class Details
    {
        public string subtotal { get; set; }
    }

    public class Payee
    {
        public string merchant_id { get; set; }
        public string email { get; set; }
    }

    public class Item_List
    {
        public Shipping_Address1 shipping_address { get; set; }
    }

    public class Shipping_Address1
    {
        public string recipient_name { get; set; }
        public string line1 { get; set; }
        public string city { get; set; }
        public string state { get; set; }
        public string postal_code { get; set; }
        public string country_code { get; set; }
    }

    public class Related_Resources
    {
        public Sale sale { get; set; }
    }

    public class Sale
    {
        public string id { get; set; }
        public string state { get; set; }
        public Amount amount { get; set; }
        public string payment_mode { get; set; }
        public string protection_eligibility { get; set; }
        public string protection_eligibility_type { get; set; }
        public Transaction_Fee transaction_fee { get; set; }
        public string parent_payment { get; set; }
        public DateTime create_time { get; set; }
        public DateTime update_time { get; set; }
        public Link[] links { get; set; }
    }

    public class Transaction_Fee
    {
        public string value { get; set; }
        public string currency { get; set; }
    }

    public class Link
    {
        public string href { get; set; }
        public string rel { get; set; }
        public string method { get; set; }
    }
}

Program.cs

// C# code to demostrate 
// https://developer.paypal.com/docs/integration/web/accept-paypal-payment/
private static int RunPaypalDemo()
{
    try
    {
        Task.Run(async () =>
        {
            HttpClient http = GetPaypalHttpClient();

            // Step 1: Get an access token
            PayPalAccessToken accessToken = await GetPayPalAccessTokenAsync(http);
            Log.Information("Access Token \n{@accessToken}", accessToken);

            // Step 2: Create the payment
            PayPalPaymentCreatedResponse createdPayment = await CreatePaypalPaymentAsync(http, accessToken);
            Log.Information("Created payment \n{@createdPayment}", createdPayment);

            // Step 3: Get the approval_url and paste it into a browser
            // It should look something like this: https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token=EC-97965369EL8295114
            var approval_url = createdPayment.links.First(x => x.rel == "approval_url").href;
            Log.Information("approval_url\n{approval_url}", approval_url);

            //
            // IMPORTANT: Stop the program here, and re-run only the section below (comment out Step 2 and Step 3) and paste in the correct paymentId and payerId
            //

            // Step 4: When paypal redirects to the return_url, we need to grab the PayerID and the paymentId and execute the payment
            var paymentId = "PAY-9LN814307S704373KK6UFTHI";
            var payerId = "LMWV7AASBDUQQ";

            PayPalPaymentExecutedResponse executedPayment = await ExecutePaypalPaymentAsync(http, accessToken, paymentId, payerId);
            Log.Information("Executed payment \n{@executedPayment}", executedPayment);

        }).Wait();

    }
    catch (Exception ex)
    {
        Log.Error(ex, "Failed to login to PalPal");
        return 1;
    }

    return 0;
}

private static HttpClient GetPaypalHttpClient()
{
    const string sandbox = "https://api.sandbox.paypal.com";

    var http = new HttpClient
    {
        BaseAddress = new Uri(sandbox),
        Timeout = TimeSpan.FromSeconds(30),
    };

    return http;
}

private static async Task<PayPalAccessToken> GetPayPalAccessTokenAsync(HttpClient http)
{
    var clientId = Config.Instance.PayPalClientId;
    var secret = Config.Instance.PayPalSecret;

    byte[] bytes = Encoding.GetEncoding("iso-8859-1").GetBytes($"{clientId}:{secret}");

    HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "/v1/oauth2/token");
    request.Headers.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(bytes));

    var form = new Dictionary<string, string>
    {
        ["grant_type"] = "client_credentials"
    };

    request.Content = new FormUrlEncodedContent(form);

    HttpResponseMessage response = await http.SendAsync(request);

    string content = await response.Content.ReadAsStringAsync();
    PayPalAccessToken accessToken = JsonConvert.DeserializeObject<PayPalAccessToken>(content);
    return accessToken;
}

private static async Task<PayPalPaymentCreatedResponse> CreatePaypalPaymentAsync(HttpClient http, PayPalAccessToken accessToken)
{
    HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "v1/payments/payment");
    request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken.access_token);

    var payment = JObject.FromObject(new
    {
        intent = "sale",
        redirect_urls = new
        {
            return_url = "http://example.com/your_redirect_url.html",
            cancel_url = "http://example.com/your_cancel_url.html"
        },
        payer = new { payment_method = "paypal" },
        transactions = JArray.FromObject(new[]
        {
            new
            {
                amount = new
                {
                    total = 7.47,
                    currency = "USD"
                }
            }
        })
    });

    request.Content = new StringContent(JsonConvert.SerializeObject(payment), Encoding.UTF8, "application/json");

    HttpResponseMessage response = await http.SendAsync(request);

    string content = await response.Content.ReadAsStringAsync();
    PayPalPaymentCreatedResponse paypalPaymentCreated = JsonConvert.DeserializeObject<PayPalPaymentCreatedResponse>(content);
    return paypalPaymentCreated;
}

private static async Task<PayPalPaymentExecutedResponse> ExecutePaypalPaymentAsync(HttpClient http, PayPalAccessToken accessToken, string paymentId, string payerId)
{
    HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, $"v1/payments/payment/{paymentId}/execute");
    request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken.access_token);

    var payment = JObject.FromObject(new
    {
        payer_id = payerId
    });

    request.Content = new StringContent(JsonConvert.SerializeObject(payment), Encoding.UTF8, "application/json");

    HttpResponseMessage response = await http.SendAsync(request);
    string content = await response.Content.ReadAsStringAsync();
    PayPalPaymentExecutedResponse executedPayment = JsonConvert.DeserializeObject<PayPalPaymentExecutedResponse>(content);
    return executedPayment;
}

Thank you so much for this one... I have successfully "ported" all of the PayPal SDK's features which we needed, using parts of Program.cs.

Great sample Jake! Is there any chance to figure out what's the PayPalAccessToken type ?
I can't see the definition in the code. Your help would be appreciated!

from where has PayPalAccessToken and other classes in Program.cs undertaken?

Thank you ... ;*

class PayPalAccessToken
{
    public string scope { get; set; }
    public string access_token { get; set; }
    public string token_type { get; set; }
    public string app_id { get; set; }
    public int expires_in { get; set; }
    public string nonce { get; set; }
}

This is the PayPalAccessToken class.

Thank you for the wonderful explanation, do you have created any sample with creditcard and debitcard?