Add logging of error codes in recaptcha response

AspNetCore.ReCaptcha.Tests/ReCaptchaServiceTests.cs

@@ -5,6 +5,8 @@
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 using Moq;
 using Moq.Protected;
@@ -14,7 +16,7 @@ namespace AspNetCore.ReCaptcha.Tests
 {
     public class ReCaptchaServiceTests
     {
-        private ReCaptchaService CreateService(HttpClient httpClient = null, Mock<IOptions<ReCaptchaSettings>> reCaptchaSettingsMock = null)
+        private ReCaptchaService CreateService(HttpClient httpClient = null, Mock<IOptions<ReCaptchaSettings>> reCaptchaSettingsMock = null, ILogger<ReCaptchaService> logger = null)
         {
             httpClient ??= new HttpClient();
 
@@ -31,7 +33,9 @@ private ReCaptchaService CreateService(HttpClient httpClient = null, Mock<IOptio
                 reCaptchaSettingsMock.Setup(x => x.Value).Returns(reCaptchaSettings);
             }
 
-            return new ReCaptchaService(httpClient, reCaptchaSettingsMock.Object);
+            logger ??= new NullLogger<ReCaptchaService>();
+
+            return new ReCaptchaService(httpClient, reCaptchaSettingsMock.Object, logger);
         }
 
         [Theory]
@@ -67,7 +71,57 @@ public void TestVerifyAsync(bool successResult)
             var result = reCaptchaService.VerifyAsync("123").Result;
 
             mockHttpMessageHandler.Protected().Verify("SendAsync", Times.Exactly(1), ItExpr.IsAny<HttpRequestMessage>(), ItExpr.IsAny<CancellationToken>());
-            Assert.Equal(reCaptchaResponse.Success, result);
+            Assert.Equal(successResult, result);
+        }
+
+        [Theory]
+        [InlineData("missing-input-secret", LogLevel.Warning, "recaptcha verify returned error code missing-input-secret, this could indicate an invalid secretkey.")]
+        [InlineData("invalid-input-secret", LogLevel.Warning, "recaptcha verify returned error code invalid-input-secret, this could indicate an invalid secretkey.")]
+        [InlineData("missing-input-response", LogLevel.Debug, "recaptcha verify returned error code missing-input-response, this indicates the user didn't succeed the captcha.")]
+        [InlineData("invalid-input-response", LogLevel.Debug, "recaptcha verify returned error code invalid-input-response, this indicates the user didn't succeed the captcha.")]
+        [InlineData("bad-request", LogLevel.Debug, "recaptcha verify returned error code bad-request.")]
+        [InlineData("timeout-or-duplicate", LogLevel.Debug, "recaptcha verify returned error code timeout-or-duplicate.")]
+        public void TestVerifyWithErrorAsync(string errorCode, LogLevel expectedLogLevel, string expectedLogMessage)
+        {
+            var reCaptchaResponse = new ReCaptchaResponse()
+            {
+                Action = "Test",
+                ChallengeTimestamp = new DateTime(2022, 2, 10, 15, 14, 13),
+                Hostname = "Test",
+                Success = false,
+                ErrorCodes = new[] { errorCode }
+            };
+
+            var mockHttpMessageHandler = new Mock<HttpMessageHandler>();
+
+            mockHttpMessageHandler.Protected()
+                .Setup<Task<HttpResponseMessage>>(
+                    "SendAsync",
+                    ItExpr.IsAny<HttpRequestMessage>(),
+                    ItExpr.IsAny<CancellationToken>())
+                .ReturnsAsync(new HttpResponseMessage { StatusCode = HttpStatusCode.OK, Content = new StringContent(JsonSerializer.Serialize(reCaptchaResponse), Encoding.UTF8,"application/json")});
+
+            var httpClient = new HttpClient(mockHttpMessageHandler.Object)
+            {
+                BaseAddress = new Uri("https://www.google.com/recaptcha/"),
+            };
+
+            var logger = new TestLogger<ReCaptchaService>();
+
+            var reCaptchaService = CreateService(httpClient, logger: logger);
+
+            var result = reCaptchaService.VerifyAsync("123").Result;
+
+            mockHttpMessageHandler.Protected().Verify("SendAsync", Times.Exactly(1), ItExpr.IsAny<HttpRequestMessage>(), ItExpr.IsAny<CancellationToken>());
+            Assert.False(reCaptchaResponse.Success);
+            Assert.False(result);
+
+            Assert.Equal(2, logger.LogEntries.Count);
+            Assert.Equal(LogLevel.Trace, logger.LogEntries[0].LogLevel);
+            Assert.Equal(@$"recaptcha response: {{""success"":false,""score"":0,""action"":""Test"",""challenge_ts"":""2022-02-10T15:14:13"",""hostname"":""Test"",""error-codes"":[""{errorCode}""]}}", logger.LogEntries[0].Message);
+
+            Assert.Equal(expectedLogLevel, logger.LogEntries[1].LogLevel);
+            Assert.Equal(expectedLogMessage, logger.LogEntries[1].Message);
         }
     }
 }

AspNetCore.ReCaptcha.Tests/TestLogger.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.Extensions.Logging;
+
+namespace AspNetCore.ReCaptcha.Tests;
+
+public class TestLogger<T> : ILogger<T>
+    where T : class
+{
+    public List<(LogLevel LogLevel, string Message)> LogEntries { get; } = new List<(LogLevel, string)>();
+
+    public IDisposable BeginScope<TState>(TState state)
+    {
+        return new NullDisposable();
+    }
+
+    public bool IsEnabled(LogLevel logLevel)
+    {
+        return true;
+    }
+
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+        LogEntries.Add((logLevel, formatter(state, exception)));
+    }
+}
+
+internal class NullDisposable : IDisposable
+{
+    public void Dispose()
+    {
+    }
+}

AspNetCore.ReCaptcha/AspNetCore.ReCaptcha.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFrameworks>netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
     <PackageId>AspNetCore.ReCaptcha</PackageId>
-    <Version>1.5.1</Version>
+    <Version>1.5.2</Version>
     <Authors>Michaelvs97,sleeuwen</Authors>
     <Description>Google ReCAPTCHA v2/v3 Library for .NET Core 3.1 and .NET 5.0/6.0</Description>
     <PackageDescription>Google ReCAPTCHA v2/v3 Library for .NET Core 3.1 and .NET 5.0/6.0</PackageDescription>

AspNetCore.ReCaptcha/ReCaptchaHelper.cs

@@ -14,6 +14,8 @@ public static class ReCaptchaHelper
     {
         private static IHttpClientBuilder AddReCaptchaServices(this IServiceCollection services)
         {
+            services.AddLogging();
+
             services.PostConfigure<ReCaptchaSettings>(settings =>
             {
                 settings.LocalizerProvider ??= (modelType, localizerFactory) => localizerFactory.Create(modelType);

AspNetCore.ReCaptcha/ReCaptchaService.cs

@@ -2,18 +2,21 @@
 using System.Net.Http;
 using System.Text.Json;
 using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
 namespace AspNetCore.ReCaptcha
 {
     internal class ReCaptchaService : IReCaptchaService
     {
         private readonly HttpClient _client;
+        private readonly ILogger<ReCaptchaService> _logger;
         private readonly ReCaptchaSettings _reCaptchaSettings;
 
-        public ReCaptchaService(HttpClient client, IOptions<ReCaptchaSettings> reCaptchaSettings)
+        public ReCaptchaService(HttpClient client, IOptions<ReCaptchaSettings> reCaptchaSettings, ILogger<ReCaptchaService> logger)
         {
             _client = client;
+            _logger = logger;
             _reCaptchaSettings = reCaptchaSettings.Value;
         }
 
@@ -42,9 +45,24 @@ public async Task<ReCaptchaResponse> GetVerifyResponseAsync(string reCaptchaResp
             var result = await _client.PostAsync("api/siteverify", body);
 
             var stringResult = await result.Content.ReadAsStringAsync();
+            _logger?.LogTrace("recaptcha response: {recaptchaResponse}", stringResult);
 
             var obj = JsonSerializer.Deserialize<ReCaptchaResponse>(stringResult);
 
+            if (obj.ErrorCodes?.Length > 0 && _logger?.IsEnabled(LogLevel.Warning) == true)
+            {
+                for (var i = 0; i < obj.ErrorCodes.Length; i++)
+                {
+                    var errorCode = obj.ErrorCodes[i];
+                    if (errorCode.EndsWith("-input-secret"))
+                        _logger?.LogWarning("recaptcha verify returned error code {ErrorCode}, this could indicate an invalid secretkey.", errorCode);
+                    else if (errorCode.EndsWith("-input-response"))
+                        _logger?.LogDebug("recaptcha verify returned error code {ErrorCode}, this indicates the user didn't succeed the captcha.", errorCode);
+                    else
+                        _logger?.LogDebug("recaptcha verify returned error code {ErrorCode}.", errorCode);
+                }
+            }
+
             return obj;
         }
     }

AspNetCore.ReCaptcha/RecaptchaResponse.cs

@@ -15,5 +15,7 @@ public class ReCaptchaResponse
         public DateTime ChallengeTimestamp { get; set; }
         [JsonPropertyName("hostname")]
         public string Hostname { get; set; }
+        [JsonPropertyName("error-codes")]
+        public string[] ErrorCodes { get; set; }
     }
 }