feat: Implement check header in emulator (#66)

Author: Mielek

src/Authoring/Configs/CheckHeaderConfig.cs

@@ -6,8 +6,8 @@ namespace Azure.ApiManagement.PolicyToolkit.Authoring;
 public record CheckHeaderConfig
 {
     public required string Name { get; init; }
-    public required string FailCheckHttpCode { get; init; }
+    public required int FailCheckHttpCode { get; init; }
     public required string FailCheckErrorMessage { get; init; }
-    public required string IgnoreCase { get; init; }
+    public required bool IgnoreCase { get; init; }
     public required string[] Values { get; init; }
 }

src/Testing/Document/MockCheckHeaderProvider.cs

@@ -35,5 +35,11 @@ internal Setup(
 
         public void WithCallback(Action<GatewayContext, CheckHeaderConfig> callback) =>
             _handler.CallbackSetup.Add((_predicate, callback).ToTuple());
+
+        public void OnCheckPass(Action<GatewayContext, CheckHeaderConfig> onCheckPass) =>
+            _handler.OnCheckPassed.Add((_predicate, onCheckPass).ToTuple());
+
+        public void OnCheckFail(Action<GatewayContext, CheckHeaderConfig> onCheckFail) =>
+            _handler.OnCheckFailed.Add((_predicate, onCheckFail).ToTuple());
     }
 }

src/Testing/Emulator/Policies/CheckHeaderHandler.cs

@@ -2,16 +2,60 @@
 // Licensed under the MIT License.
 
 using Azure.ApiManagement.PolicyToolkit.Authoring;
+using Azure.ApiManagement.PolicyToolkit.Testing.Expressions;
 
 namespace Azure.ApiManagement.PolicyToolkit.Testing.Emulator.Policies;
 
 [Section(nameof(IInboundContext))]
 internal class CheckHeaderHandler : PolicyHandler<CheckHeaderConfig>
 {
+    public List<Tuple<
+        Func<GatewayContext, CheckHeaderConfig, bool>,
+        Action<GatewayContext, CheckHeaderConfig>
+    >> OnCheckPassed { get; } = new();
+
+    public List<Tuple<
+        Func<GatewayContext, CheckHeaderConfig, bool>,
+        Action<GatewayContext, CheckHeaderConfig>
+    >> OnCheckFailed { get; } = new();
+
     public override string PolicyName => nameof(IInboundContext.CheckHeader);
 
     protected override void Handle(GatewayContext context, CheckHeaderConfig config)
     {
-        throw new NotImplementedException();
+        bool pass = false;
+        if (context.Request.Headers.TryGetValue(config.Name, out var values) && values.Length == 1)
+        {
+            pass = config.Values.Length == 0 || config.Values.Contains(values[0], ValueComparer(config));
+        }
+
+        if (pass)
+        {
+            OnCheckPassed.Find(tuple => tuple.Item1(context, config))?.Item2(context, config);
+            return;
+        }
+
+        context.Response = new MockResponse()
+        {
+            StatusCode = config.FailCheckHttpCode,
+            // StatusReason = GetStatusReason(config.FailCheckHttpCode), TODO: Create status reason mapper
+            Headers = { { "Content-Type", ["application/json"] } },
+            Body =
+            {
+                Content = $$"""
+                            {
+                              "statusCode": {{config.FailCheckHttpCode}},
+                              "message": "{{config.FailCheckErrorMessage}}"
+                            }
+                            """
+            }
+        };
+
+        OnCheckFailed.Find(tuple => tuple.Item1(context, config))?.Item2(context, config);
+        throw new FinishSectionProcessingException();
     }
+
+    private static StringComparer ValueComparer(CheckHeaderConfig config) => config.IgnoreCase
+        ? StringComparer.InvariantCultureIgnoreCase
+        : StringComparer.InvariantCulture;
 }

test/Test.Testing/Emulator/Policies/CheckHeaderTests.cs

@@ -0,0 +1,78 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using Azure.ApiManagement.PolicyToolkit.Authoring;
+using Azure.ApiManagement.PolicyToolkit.Testing;
+using Azure.ApiManagement.PolicyToolkit.Testing.Document;
+
+using Newtonsoft.Json.Linq;
+
+namespace Test.Emulator.Emulator.Policies;
+
+[TestClass]
+public class CheckHeaderTests
+{
+    class SimpleCheckHeader : IDocument
+    {
+        public void Inbound(IInboundContext context)
+        {
+            context.CheckHeader(new CheckHeaderConfig()
+            {
+                Name = "Test",
+                FailCheckHttpCode = 401,
+                FailCheckErrorMessage = "Request do not contain test header",
+                IgnoreCase = false,
+                Values = []
+            });
+        }
+    }
+
+    [TestMethod]
+    public void CheckHeader_Callback()
+    {
+        var test = new SimpleCheckHeader().AsTestDocument();
+        var executedCallback = false;
+        test.SetupInbound().CheckHeader().WithCallback((_, _) =>
+        {
+            executedCallback = true;
+        });
+
+        test.RunInbound();
+
+        executedCallback.Should().BeTrue();
+    }
+
+    [TestMethod]
+    public void CheckHeader_PassExistenceCheck()
+    {
+        var test = new SimpleCheckHeader().AsTestDocument();
+        test.Context.Request.Headers["Test"] = ["test"];
+
+        test.RunInbound();
+
+        var response = test.Context.Response;
+        response.StatusCode.Should().NotBe(401);
+    }
+
+    [TestMethod]
+    public void CheckHeader_FailExistenceCheck()
+    {
+        var test = new SimpleCheckHeader().AsTestDocument();
+
+        test.RunInbound();
+
+        var response = test.Context.Response;
+        response.StatusCode.Should().Be(401);
+        response.Headers.Should().ContainKey("Content-Type")
+            .WhoseValue.Should().ContainSingle()
+            .Which.Should().Be("application/json");
+        response.Body.Content.Should().NotBeNullOrWhiteSpace();
+        var body = response.Body.As<JObject>();
+        body.Should().ContainKey("statusCode")
+            .WhoseValue.Should().NotBeNull().And
+            .Subject.Value<int>().Should().Be(401);
+        body.Should().ContainKey("message")
+            .WhoseValue.Should().NotBeNull().And
+            .Subject.Value<string>().Should().Be("Request do not contain test header");
+    }
+}