crexi-dev · MichaelPGriffin · Dec 10, 2024 · Dec 10, 2024 · Dec 10, 2024 · Dec 10, 2024
diff --git a/RateLimiter.Tests/EuropeanRateLimiterPolicyTests.cs b/RateLimiter.Tests/EuropeanRateLimiterPolicyTests.cs
@@ -0,0 +1,96 @@
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Configuration;
+using Moq;
+using RateLimiter.Services;
+
+namespace RateLimiter.Tests
+{
+    public class EuropeanRateLimiterPolicyTests
+    {
+        [Fact]
+        public void TestRateLimitingNotAppliedBelowOrEqualToMaxRequests()
+        {
+            const int maxAllowedRequestsPerFixedWindow = 2;
+            const string unitOfTime = "Minute";
+            const int cacheExpirationMinutes = 5;
+            var mockConfig = BuildTestConfig(maxAllowedRequestsPerFixedWindow, unitOfTime, cacheExpirationMinutes);
+
+            using var memoryCache = new MemoryCache(new MemoryCacheOptions());
+            var clientBehaviorCache = new ClientBehaviorCache(memoryCache, mockConfig.Object);
+            var policy = new EuropeanRateLimiterPolicy(clientBehaviorCache, mockConfig.Object);
+
+            string testApiKey = "test-api-key";
+            var initialRequestTime = new DateTime(2024, 12, 9, 10, 10, 0);
+            string noRateLimitingExpectedMessage = $"Rate limiting should not apply until exceeding {maxAllowedRequestsPerFixedWindow} requests per period";
+
+            clientBehaviorCache.Add(testApiKey, initialRequestTime);
+            Assert.False(policy.IsApplicable(testApiKey, initialRequestTime), noRateLimitingExpectedMessage);
+
+            var secondRequestTime = initialRequestTime.AddSeconds(58);
+            clientBehaviorCache.Add(testApiKey, secondRequestTime);
+            Assert.False(policy.IsApplicable(testApiKey, secondRequestTime), noRateLimitingExpectedMessage);
+        }
+
+        [Fact]
+        public void TestRateLimitingAppliedWhenMaxRequestsExceeded()
+        {
+            const int maxAllowedRequestsPerFixedWindow = 2;
+            const string unitOfTime = "Minute";
+            const int cacheExpirationMinutes = 5;
+            var mockConfig = BuildTestConfig(maxAllowedRequestsPerFixedWindow, unitOfTime, cacheExpirationMinutes);
+
+            using var memoryCache = new MemoryCache(new MemoryCacheOptions());
+            var clientBehaviorCache = new ClientBehaviorCache(memoryCache, mockConfig.Object);
+            var policy = new EuropeanRateLimiterPolicy(clientBehaviorCache, mockConfig.Object);
+
+            string testApiKey = "test-api-key";
+            var initialRequestTime = new DateTime(2024, 12, 9, 10, 10, 0);
+            var secondRequestTime = initialRequestTime.AddSeconds(58);
+            var thirdRequestTime = initialRequestTime.AddSeconds(59);
+
+            clientBehaviorCache.Add(testApiKey, initialRequestTime);
+            clientBehaviorCache.Add(testApiKey, secondRequestTime);
+            clientBehaviorCache.Add(testApiKey, thirdRequestTime);
+
+            string rateLimitingExpectedMessage = $"Rate limiting applies after exceeding {maxAllowedRequestsPerFixedWindow} requests per period";
+            Assert.True(policy.IsApplicable(testApiKey, thirdRequestTime), rateLimitingExpectedMessage);
+        }
+
+        [Fact]
+        public void TestCanExceedRateLimitByAllocatingRequestsAcrossDistinctFixedWindows()
+        {
+            const int maxAllowedRequestsPerFixedWindow = 2;
+            const string unitOfTime = "Minute";
+            const int cacheExpirationMinutes = 5;
+            var mockConfig = BuildTestConfig(maxAllowedRequestsPerFixedWindow, unitOfTime, cacheExpirationMinutes);
+
+            using var memoryCache = new MemoryCache(new MemoryCacheOptions());
+            var clientBehaviorCache = new ClientBehaviorCache(memoryCache, mockConfig.Object);
+            var policy = new EuropeanRateLimiterPolicy(clientBehaviorCache, mockConfig.Object);
+
+            string testApiKey = "test-api-key";
+            var firstRequestTime = new DateTime(2024, 12, 9, 10, 10, 58);
+            var secondRequestTime = new DateTime(2024, 12, 9, 10, 10, 59);
+            var thirdRequestTime = new DateTime(2024, 12, 9, 10, 11, 1);
+            var finalRequestTime = new DateTime(2024, 12, 9, 10, 11, 2);
+
+            clientBehaviorCache.Add(testApiKey, firstRequestTime);
+            clientBehaviorCache.Add(testApiKey, secondRequestTime);
+            clientBehaviorCache.Add(testApiKey, thirdRequestTime);
+            clientBehaviorCache.Add(testApiKey, finalRequestTime);
+
+            string msg = "Should be able to exceed fixed window rate limit by allocating requests at end of window and at start of the next.";
+            Assert.False(policy.IsApplicable(testApiKey, finalRequestTime), msg);
+        }
+
+        private static Mock<IConfiguration> BuildTestConfig(int maxAllowedRequestsPerFixedWindow, string unitOfTime, int cacheExpirationMinutes)
+        {
+            var mockConfig = new Mock<IConfiguration>();
+            mockConfig.Setup(c => c["RateLimiting:FixedWindow:MaxRequests"]).Returns(maxAllowedRequestsPerFixedWindow.ToString());
+            mockConfig.Setup(c => c["RateLimiting:FixedWindow:UnitOfTime"]).Returns(unitOfTime);
+            mockConfig.Setup(c => c["RateLimiting:CacheExpirationMinutes"]).Returns(cacheExpirationMinutes.ToString());
+
+            return mockConfig;
+        }
+    }
+}
diff --git a/RateLimiter.Tests/NorthAmericanRateLimiterPolicyTests.cs b/RateLimiter.Tests/NorthAmericanRateLimiterPolicyTests.cs
@@ -0,0 +1,102 @@
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Configuration;
+using Moq;
+using RateLimiter.Services;
+
+namespace RateLimiter.Tests
+{
+    public class NorthAmericanRateLimiterPolicyTests
+    {
+        [Fact]
+        public void TestRateLimitingNotAppliedBelowOrEqualToMaxRequests()
+        {
+            const int maxAllowedRequestsPerSlidingWindow = 3;
+            const int windowLengthSeconds = 30;
+            const int cacheExpirationMinutes = 5;
+            var mockConfig = BuildTestConfig(maxAllowedRequestsPerSlidingWindow, windowLengthSeconds, cacheExpirationMinutes);
+
+            string testApiKey = "test-api-key";
+            var firstRequestTime = new DateTime(2024, 12, 9, 10, 10, 0);
+            var secondRequestTime = firstRequestTime.AddSeconds(1);
+            var thirdRequestTime = firstRequestTime.AddSeconds(2);
+
+            using var memoryCache = new MemoryCache(new MemoryCacheOptions());
+            var clientBehaviorCache = new ClientBehaviorCache(memoryCache, mockConfig.Object);
+            var policy = new NorthAmericanRateLimiterPolicy(clientBehaviorCache, mockConfig.Object);
+
+            clientBehaviorCache.Add(testApiKey, firstRequestTime);
+            clientBehaviorCache.Add(testApiKey, secondRequestTime);
+            clientBehaviorCache.Add(testApiKey, thirdRequestTime);
+
+            string msg = "No rate limiting expected if number of requests equal to max allowed";
+            Assert.False(policy.IsApplicable(testApiKey, thirdRequestTime), msg);
+        }
+
+        [Fact]
+        public void TestRateLimitingAppliedWhenMaxRequestsExceeded()
+        {
+            const int maxAllowedRequestsPerSlidingWindow = 3;
+            const int windowLengthSeconds = 30;
+            const int cacheExpirationMinutes = 5;
+            var mockConfig = BuildTestConfig(maxAllowedRequestsPerSlidingWindow, windowLengthSeconds, cacheExpirationMinutes);
+
+            string testApiKey = "test-api-key";
+            var firstRequestTime = new DateTime(2024, 12, 9, 10, 10, 0);
+            var secondRequestTime = firstRequestTime.AddSeconds(1);
+            var thirdRequestTime = firstRequestTime.AddSeconds(28);
+            var fourthRequestTime = firstRequestTime.AddSeconds(windowLengthSeconds);
+
+            using var memoryCache = new MemoryCache(new MemoryCacheOptions());
+            var clientBehaviorCache = new ClientBehaviorCache(memoryCache, mockConfig.Object);
+            var policy = new NorthAmericanRateLimiterPolicy(clientBehaviorCache, mockConfig.Object);
+
+            clientBehaviorCache.Add(testApiKey, firstRequestTime);
+            clientBehaviorCache.Add(testApiKey, secondRequestTime);
+            clientBehaviorCache.Add(testApiKey, thirdRequestTime);
+            clientBehaviorCache.Add(testApiKey, fourthRequestTime);
+
+            string msg = "Rate limiting is expected when request count exceeds maximum allowed per period";
+            Assert.True(policy.IsApplicable(testApiKey, thirdRequestTime), msg);
+        }
+
+        [Fact]
+        public void TestRateLimiterDoesNotApplyWhenRequestsAreDistributedOverTime()
+        {
+            const int maxAllowedRequestsPerSlidingWindow = 3;
+            const int windowLengthSeconds = 30;
+            const int cacheExpirationMinutes = 5;
+            var mockConfig = BuildTestConfig(maxAllowedRequestsPerSlidingWindow, windowLengthSeconds, cacheExpirationMinutes);
+
+            string testApiKey = "test-api-key";
+            var firstRequestTime = new DateTime(2024, 12, 9, 10, 10, 0);
+            var secondRequestTime = firstRequestTime.AddSeconds(1);
+            var thirdRequestTime = firstRequestTime.AddSeconds(2);
+
+            // This request is more than 30 seconds removed from initial request. No rate limiting expected.
+            var fourthRequestTime = firstRequestTime.AddSeconds(windowLengthSeconds + 1);
+
+            using var memoryCache = new MemoryCache(new MemoryCacheOptions());
+            var clientBehaviorCache = new ClientBehaviorCache(memoryCache, mockConfig.Object);
+            var policy = new NorthAmericanRateLimiterPolicy(clientBehaviorCache, mockConfig.Object);
+
+            clientBehaviorCache.Add(testApiKey, firstRequestTime);
+            clientBehaviorCache.Add(testApiKey, secondRequestTime);
+            clientBehaviorCache.Add(testApiKey, thirdRequestTime);
+            clientBehaviorCache.Add(testApiKey, fourthRequestTime);
+
+            string msg = "Rate limiter should allow many requests as long as they don't fall into same sliding window";
+            Assert.False(policy.IsApplicable(testApiKey, fourthRequestTime), msg);
+        }
+
+        private static Mock<IConfiguration> BuildTestConfig(int maxAllowedRequestsPerSlidingWindow, int windowLengthSeconds, int cacheExpirationMinutes)
+        {
+            var mockConfig = new Mock<IConfiguration>();
+            mockConfig.Setup(c => c["RateLimiting:SlidingWindow:MaxRequests"]).Returns(maxAllowedRequestsPerSlidingWindow.ToString());
+            mockConfig.Setup(c => c["RateLimiting:SlidingWindow:WindowLengthSeconds"]).Returns(windowLengthSeconds.ToString());
+            mockConfig.Setup(c => c["RateLimiting:CacheExpirationMinutes"]).Returns(cacheExpirationMinutes.ToString());
+
+            return mockConfig;
+        }
+    }
+
+}
diff --git a/RateLimiter.Tests/RateLimiter.Tests.csproj b/RateLimiter.Tests/RateLimiter.Tests.csproj
@@ -1,15 +1,28 @@
-<Project Sdk="Microsoft.NET.Sdk">
-  <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
-    <LangVersion>latest</LangVersion>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
-  <ItemGroup>
-    <ProjectReference Include="..\RateLimiter\RateLimiter.csproj" />
-  </ItemGroup>
-  <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
-    <PackageReference Include="NUnit" Version="3.13.3" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.4.2" />
-  </ItemGroup>
-</Project>  
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.5.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\RateLimiter\RateLimiter.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>
diff --git a/RateLimiter.Tests/RateLimiterTest.cs b/RateLimiter.Tests/RateLimiterTest.cs
diff --git a/RateLimiter.sln b/RateLimiter.sln
@@ -1,36 +1,36 @@
-
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.26730.15
-MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "RateLimiter", "RateLimiter\RateLimiter.csproj", "{36F4BDC6-D3DA-403A-8DB7-0C79F94B938F}"
-EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "RateLimiter.Tests", "RateLimiter.Tests\RateLimiter.Tests.csproj", "{C4F9249B-010E-46BE-94B8-DD20D82F1E60}"
-EndProject
-Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{9B206889-9841-4B5E-B79B-D5B2610CCCFF}"
-	ProjectSection(SolutionItems) = preProject
-		README.md = README.md
-	EndProjectSection
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|Any CPU = Debug|Any CPU
-		Release|Any CPU = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{36F4BDC6-D3DA-403A-8DB7-0C79F94B938F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{36F4BDC6-D3DA-403A-8DB7-0C79F94B938F}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{36F4BDC6-D3DA-403A-8DB7-0C79F94B938F}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{36F4BDC6-D3DA-403A-8DB7-0C79F94B938F}.Release|Any CPU.Build.0 = Release|Any CPU
-		{C4F9249B-010E-46BE-94B8-DD20D82F1E60}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{C4F9249B-010E-46BE-94B8-DD20D82F1E60}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{C4F9249B-010E-46BE-94B8-DD20D82F1E60}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{C4F9249B-010E-46BE-94B8-DD20D82F1E60}.Release|Any CPU.Build.0 = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
-	GlobalSection(ExtensibilityGlobals) = postSolution
-		SolutionGuid = {67D05CB6-8603-4C96-97E5-C6CEFBEC6134}
-	EndGlobalSection
-EndGlobal
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.12.35514.174
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{9B206889-9841-4B5E-B79B-D5B2610CCCFF}"
+	ProjectSection(SolutionItems) = preProject
+		README.md = README.md
+	EndProjectSection
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "RateLimiter", "RateLimiter\RateLimiter.csproj", "{96053C2C-25E5-4DC1-80B8-B6B4102C5585}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "RateLimiter.Tests", "RateLimiter.Tests\RateLimiter.Tests.csproj", "{E66B10CF-321E-4AFF-AD4B-EF3BF9D15D7D}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{96053C2C-25E5-4DC1-80B8-B6B4102C5585}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{96053C2C-25E5-4DC1-80B8-B6B4102C5585}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{96053C2C-25E5-4DC1-80B8-B6B4102C5585}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{96053C2C-25E5-4DC1-80B8-B6B4102C5585}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E66B10CF-321E-4AFF-AD4B-EF3BF9D15D7D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E66B10CF-321E-4AFF-AD4B-EF3BF9D15D7D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E66B10CF-321E-4AFF-AD4B-EF3BF9D15D7D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E66B10CF-321E-4AFF-AD4B-EF3BF9D15D7D}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {67D05CB6-8603-4C96-97E5-C6CEFBEC6134}
+	EndGlobalSection
+EndGlobal
diff --git a/RateLimiter/Controllers/WeatherForecastController.cs b/RateLimiter/Controllers/WeatherForecastController.cs
@@ -0,0 +1,33 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace RateLimiter.Controllers
+{
+    [ApiController]
+    [Route("[controller]")]
+    public class WeatherForecastController : ControllerBase
+    {
+        private static readonly string[] Summaries = new[]
+        {
+            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
+        };
+
+        private readonly ILogger<WeatherForecastController> _logger;
+
+        public WeatherForecastController(ILogger<WeatherForecastController> logger)
+        {
+            _logger = logger;
+        }
+
+        [HttpGet(Name = "GetWeatherForecast")]
+        public IEnumerable<WeatherForecast> Get()
+        {
+            return Enumerable.Range(1, 5).Select(index => new WeatherForecast
+            {
+                Date = DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
+                TemperatureC = Random.Shared.Next(-20, 55),
+                Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+            })
+            .ToArray();
+        }
+    }
+}