monograph: add support for webrisk api for analyzing urls for pro users

Streetwriters.Common/Constants.cs

@@ -70,6 +70,7 @@ namespace Streetwriters.Common
         public static string SSE_CERT_KEY_PATH => Environment.GetEnvironmentVariable("SSE_CERT_KEY_PATH");
 
         // internal
+        public static string WEBRISK_API_URI => Environment.GetEnvironmentVariable("WEBRISK_API_URI");
         public static string MONGODB_CONNECTION_STRING => Environment.GetEnvironmentVariable("MONGODB_CONNECTION_STRING");
         public static string MONGODB_DATABASE_NAME => Environment.GetEnvironmentVariable("MONGODB_DATABASE_NAME");
         public static int SUBSCRIPTIONS_SERVER_PORT => int.Parse(Environment.GetEnvironmentVariable("SUBSCRIPTIONS_SERVER_PORT") ?? "80");

Streetwriters.Common/Interfaces/IURLAnalyzer.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using MimeKit;
+using MimeKit.Cryptography;
+using Streetwriters.Common.Models;
+
+namespace Streetwriters.Common.Interfaces
+{
+    public interface IURLAnalyzer
+    {
+        Task<bool> IsURLSafeAsync(string uri);
+    }
+}

Streetwriters.Common/Services/URLAnalyzer.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Net.Http;
+using System.Net.Http.Json;
+using System.Threading.Tasks;
+using Streetwriters.Common.Interfaces;
+
+namespace Streetwriters.Common.Services
+{
+    struct Threat
+    {
+        public string[]? ThreatTypes { get; set; }
+    }
+    struct WebRiskAPIResponse
+    {
+        public Threat Threat { get; set; }
+    }
+
+    public class URLAnalyzer : IURLAnalyzer, IDisposable
+    {
+        private readonly HttpClient httpClient = new();
+
+        public async Task<bool> IsURLSafeAsync(string uri)
+        {
+            if (string.IsNullOrEmpty(Constants.WEBRISK_API_URI)) return true;
+            var response = await httpClient.PostAsJsonAsync(Constants.WEBRISK_API_URI, new { uri });
+            if (!response.IsSuccessStatusCode) return true;
+            var json = await response.Content.ReadFromJsonAsync<WebRiskAPIResponse>();
+            return json.Threat.ThreatTypes == null || json.Threat.ThreatTypes.Length == 0;
+        }
+
+        void IDisposable.Dispose()
+        {
+            httpClient.Dispose();
+        }
+    }
+}

Streetwriters.Common/Streetwriters.Common.csproj

@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>