paypal client and stub out webhook

2025-07-10 04:14:41 -05:00 · 2019-02-01 17:16:28 -05:00
parent 9882815e4a
commit f3b5068aba
6 changed files with 246 additions and 7 deletions
--- a/src/Billing/Utilities/PaypalClient.cs
+++ b/src/Billing/Utilities/PaypalClient.cs
@ -0,0 +1,160 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Newtonsoft.Json;
+
+namespace Bit.Billing.Utilities
+{
+    public class PaypalClient
+    {
+        private readonly HttpClient _httpClient = new HttpClient();
+        private readonly string _baseApiUrl;
+        private readonly string _clientId;
+        private readonly string _clientSecret;
+
+        private AuthResponse _authResponse;
+
+        public PaypalClient(BillingSettings billingSettings)
+        {
+            _baseApiUrl = _baseApiUrl = !billingSettings.Paypal.Production ? "https://api.sandbox.paypal.com/{0}" :
+                "https://api.paypal.com/{0}";
+            _clientId = billingSettings.Paypal.ClientId;
+            _clientSecret = billingSettings.Paypal.ClientSecret;
+        }
+
+        public async Task<bool> VerifyWebhookAsync(string webhookJson, IHeaderDictionary headers, string webhookId)
+        {
+            if(webhookJson == null)
+            {
+                throw new ArgumentException("No webhook json.");
+            }
+
+            if(headers == null)
+            {
+                throw new ArgumentException("No headers.");
+            }
+
+            if(!headers.ContainsKey("PAYPAL-TRANSMISSION-ID"))
+            {
+                return false;
+            }
+
+            await AuthIfNeededAsync();
+
+            var req = new HttpRequestMessage
+            {
+                Method = HttpMethod.Post,
+                RequestUri = new Uri(string.Format(_baseApiUrl, "v1/notifications/verify-webhook-signature"))
+            };
+            req.Headers.Authorization = new AuthenticationHeaderValue(
+                _authResponse.TokenType, _authResponse.AccessToken);
+            req.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+
+            var verifyRequest = new VerifyWebookRequest
+            {
+                AuthAlgo = headers["PAYPAL-AUTH-ALGO"],
+                CertUrl = headers["PAYPAL-CERT-URL"],
+                TransmissionId = headers["PAYPAL-TRANSMISSION-ID"],
+                TransmissionTime = headers["PAYPAL-TRANSMISSION-TIME"],
+                TransmissionSig = headers["PAYPAL-TRANSMISSION-SIG"],
+                WebhookId = webhookId
+            };
+            var verifyRequestJson = JsonConvert.SerializeObject(verifyRequest);
+            verifyRequestJson = verifyRequestJson.Replace("\"__WEBHOOK_BODY__\"", webhookJson);
+            req.Content = new StringContent(verifyRequestJson, Encoding.UTF8, "application/json");
+
+            var response = await _httpClient.SendAsync(req);
+            if(!response.IsSuccessStatusCode)
+            {
+                throw new Exception("Failed to verify webhook");
+            }
+
+            var responseContent = await response.Content.ReadAsStringAsync();
+            var verifyResponse = JsonConvert.DeserializeObject<VerifyWebookResponse>(responseContent);
+            return verifyResponse.Verified;
+        }
+
+        private async Task<bool> AuthIfNeededAsync()
+        {
+            if(_authResponse?.Expired ?? true)
+            {
+                var req = new HttpRequestMessage
+                {
+                    Method = HttpMethod.Post,
+                    RequestUri = new Uri(string.Format(_baseApiUrl, "v1/oauth2/token"))
+                };
+                var authVal = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{_clientId}:{_clientSecret}"));
+                req.Headers.Authorization = new AuthenticationHeaderValue("Basic", authVal);
+                req.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+                req.Content = new FormUrlEncodedContent(new[]
+                {
+                    new KeyValuePair<string, string>("grant_type", "client_credentials")
+                });
+
+                var response = await _httpClient.SendAsync(req);
+                if(!response.IsSuccessStatusCode)
+                {
+                    throw new Exception("Failed to auth with PayPal");
+                }
+
+                var responseContent = await response.Content.ReadAsStringAsync();
+                _authResponse = JsonConvert.DeserializeObject<AuthResponse>(responseContent);
+                return true;
+            }
+            return false;
+        }
+
+        public class VerifyWebookRequest
+        {
+            [JsonProperty("auth_algo")]
+            public string AuthAlgo { get; set; }
+            [JsonProperty("cert_url")]
+            public string CertUrl { get; set; }
+            [JsonProperty("transmission_id")]
+            public string TransmissionId { get; set; }
+            [JsonProperty("transmission_sig")]
+            public string TransmissionSig { get; set; }
+            [JsonProperty("transmission_time")]
+            public string TransmissionTime { get; set; }
+            [JsonProperty("webhook_event")]
+            public string WebhookEvent { get; set; } = "__WEBHOOK_BODY__";
+            [JsonProperty("webhook_id")]
+            public string WebhookId { get; set; }
+        }
+
+        public class VerifyWebookResponse
+        {
+            [JsonProperty("verification_status")]
+            public string VerificationStatus { get; set; }
+            public bool Verified => VerificationStatus == "SUCCESS";
+        }
+
+        public class AuthResponse
+        {
+            private DateTime _created;
+
+            public AuthResponse()
+            {
+                _created = DateTime.UtcNow;
+            }
+
+            [JsonProperty("scope")]
+            public string Scope { get; set; }
+            [JsonProperty("nonce")]
+            public string Nonce { get; set; }
+            [JsonProperty("access_token")]
+            public string AccessToken { get; set; }
+            [JsonProperty("token_type")]
+            public string TokenType { get; set; }
+            [JsonProperty("app_id")]
+            public string AppId { get; set; }
+            [JsonProperty("expires_in")]
+            public long ExpiresIn { get; set; }
+            public bool Expired => DateTime.UtcNow > _created.AddSeconds(ExpiresIn - 30);
+        }
+    }
+}