Lifecycle Hooks (#1)

* Spike out an idea for the WebApplicationBuilder API. * Call onRequest on every request. * Get rid of intermediate Build() step. * Implement lifecycle hooks. * Refactor builder a little.
craigjbass · Nov 2, 2019 · 35f589a · 35f589a
1 parent 8b17b3d
commit 35f589a
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Showing 10 changed files with 223 additions and 100 deletions.
diff --git a/Frank.EndToEndTests/FrankTcpConnectionTest.cs b/Frank.EndToEndTests/FrankTcpConnectionTest.cs
@@ -19,6 +19,7 @@ public class FrankTcpConnectionTest
         private IWebApplication _webApplication;
         private IRestResponse _response;
         private int _port;
+        private bool _expectExceptionInTeardown = false;
 
         private void MakeGetRequest(string path)
         {
@@ -50,25 +51,38 @@ public void SetUp()
         {
             _port = 8019;
             _builder = Server.Configure();
+            _expectExceptionInTeardown = false;
         }
 
         [TearDown]
         public void TearDown()
         {
-            StopFrank();
+            var thrown = false;
+            try
+            {
+                StopFrank();
+            }
+            catch (Exception e)
+            {
+                if (!_expectExceptionInTeardown) throw e;
+
+                thrown = true;
+            }
+
+            if (_expectExceptionInTeardown && !thrown)
+            {
+                throw new Exception("Expected an exception, but one was not thrown.");
+            }
         }
 
         private void StartFrank()
         {
-            _builder.ListenOn(_port);
-            _webApplication = _builder.Build();
-            _webApplication.Start();
+            _webApplication = _builder.StartListeningOn(_port);
         }
 
         private void StartFrankWithRoutes(Action<IRouteConfigurer> action)
         {
-            _builder.WithRoutes(action);
-            _builder.ListenOn(_port);
+            _builder.OnRequest(action);
             StartFrank();
         }
 
@@ -194,5 +208,39 @@ public void CanDeserializeIncomingPostRequest()
             processedRequest?.Body.Should().Be("\"This is the body!!\"");
             processedRequest?.Headers["x-api-key"].Should().Be("1234supersecure");
         }
+
+        [Test]
+        public void CanExecuteBeforeAndAfterHandlers()
+        {
+            var customContext = new LifecycleHooksSpy();
+            _builder
+                .Before(() =>
+                {
+                    customContext.Before();
+                    return customContext;
+                })
+                .After(context => { context.After(); })
+                .OnRequest(((route, context) =>
+                {
+                    context.Request();
+                    route.Get("/").To(() =>
+                    {
+                        context.RouteHandler();
+                        throw new Exception();
+                    });
+                }));
+
+            StartFrank();
+
+            var response = new RestClient("http://127.0.0.1:8019/").Execute(
+                new RestRequest("/", Method.GET)
+            );
+
+            customContext._list.Should().ContainInOrder(
+                "before", "request", "route-handler", "after"
+            );
+
+            _expectExceptionInTeardown = true;
+        }
     }
 }
diff --git a/Frank.EndToEndTests/FrankTestHarnessConnectionTest.cs b/Frank.EndToEndTests/FrankTestHarnessConnectionTest.cs
@@ -1,8 +1,10 @@
+using System;
 using System.Text;
 using FluentAssertions;
 using Frank.API.WebDevelopers;
 using Frank.API.WebDevelopers.DTO;
 using NUnit.Framework;
+using static Frank.API.WebDevelopers.DTO.ResponseBuilders;
 
 namespace Frank.EndToEndTests
 {
@@ -11,9 +13,7 @@ public class FrankTestHarnessConnectionTest
         [Test]
         public void CanMakeTestRequestAndRespondWith404()
         {
-            ITestWebApplication webApplication = Server.Configure().ForTesting().Build();
-
-            webApplication.Start();
+            ITestWebApplication webApplication = Server.Configure().StartTesting();
 
             var response = webApplication.Execute(new Request());
 
@@ -25,39 +25,62 @@ public void CanRouteToARoute()
         {
             ITestWebApplication webApplication = Server
                 .Configure()
-                .WithRoutes(
-                    c => c.Get("/").To(request => ResponseBuilders.Ok().WithBody(new { a = 123 }))
-                ).ForTesting()
-                .Build();
-
-            webApplication.Start();
+                .OnRequest(
+                    c => c.Get("/").To(request => Ok().WithBody(new {a = 123}))
+                ).StartTesting();
 
             var response = webApplication.Execute(new Request());
 
             webApplication.Stop();
-            
+
             response.Status.Should().Be(200);
             Encoding.UTF8.GetString(response.Body).Should().Be("{\"a\":123}");
         }
-        
+
         [Test]
-        public void CanDoThing()
+        public void ItCallsOnRequestOncePerRequest()
         {
+            var i = 0;
             ITestWebApplication webApplication = Server
                 .Configure()
-                .WithRoutes(
-                    c => c.Get("/").To(request => ResponseBuilders.Ok().WithBody(new { a = 123 }))
-                ).ForTesting()
-                .Build();
+                .OnRequest(
+                    _ => i++
+                ).StartTesting();
 
-            webApplication.Start();
-
-            var response = webApplication.Execute(new Request());
+            webApplication.Execute(new Request());
+            webApplication.Execute(new Request());
 
             webApplication.Stop();
-
-            response.Status.Should().Be(200);
-            Encoding.UTF8.GetString(response.Body).Should().Be("{\"a\":123}");
+            i.Should().Be(2);
+        }
+
+        [Test]
+        public void CanExecuteBeforeAndAfterHandlers()
+        {
+            var customContext = new LifecycleHooksSpy();
+            var webApplication = Server.Configure()
+                .Before(() =>
+                {
+                    customContext.Before();
+                    return customContext;
+                })
+                .After(context => { context.After(); })
+                .OnRequest(((configurer, context) =>
+                {
+                    context.Request();
+                    configurer.Get("/").To(() =>
+                    {
+                        context.RouteHandler();
+                        throw new Exception();
+                    });
+                }))
+                .StartTesting();
+
+            webApplication.Execute(new Request());
+
+            customContext._list.Should().ContainInOrder(
+                "before", "request", "route-handler", "after"
+            );
         }
     }
 }
diff --git a/Frank.EndToEndTests/LifecycleHooksSpy.cs b/Frank.EndToEndTests/LifecycleHooksSpy.cs
@@ -0,0 +1,29 @@
+using System.Collections.Generic;
+
+namespace Frank.EndToEndTests
+{
+    class LifecycleHooksSpy
+    {
+        public List<string> _list = new List<string>();
+
+        public void Before()
+        {
+            _list.Add("before");
+        }
+
+        public void After()
+        {
+            _list.Add("after");
+        }
+
+        public void Request()
+        {
+            _list.Add("request");
+        }
+
+        public void RouteHandler()
+        {
+            _list.Add("route-handler");
+        }
+    }
+}
diff --git a/Frank/API/WebDevelopers/IWebApplication.cs b/Frank/API/WebDevelopers/IWebApplication.cs
@@ -2,6 +2,7 @@ namespace Frank.API.WebDevelopers
 {
     public interface IWebApplication
     {
+        //todo: this is an internally used method only.
         void Start();
         void Stop();
     }

diff --git a/Frank/API/WebDevelopers/IWebApplicationBuilder.cs b/Frank/API/WebDevelopers/IWebApplicationBuilder.cs
@@ -1,13 +1,18 @@
 using System;
-using Frank.Internals;
 
 namespace Frank.API.WebDevelopers
 {
     public interface IWebApplicationBuilder
     {
-        IWebApplicationBuilder WithRoutes(Action<IRouteConfigurer> action);
-        IWebApplicationBuilder ListenOn(int port);
-        IWebApplication Build();
-        ITestWebApplicationBuilder ForTesting();
+        IWebApplicationBuilder OnRequest(Action<IRouteConfigurer> action);
+        IWebApplicationBuilderWithBefore<T> Before<T>(Func<T> onBefore);
+        IWebApplication StartListeningOn(int port);
+        ITestWebApplication StartTesting();
+    }
+
+    public interface IWebApplicationBuilderWithBefore<T>
+    {
+        IWebApplicationBuilderWithBefore<T> After(Action<T> onAfter);
+        IWebApplicationBuilder OnRequest(Action<IRouteConfigurer, T> action);
     }
 }
diff --git a/Frank/Frank.csproj b/Frank/Frank.csproj
@@ -7,6 +7,7 @@
         <Authors>[email protected]</Authors>
         <RepositoryUrl>https://github.com/craigjbass/Frank</RepositoryUrl>
         <LangVersion>8</LangVersion>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     </PropertyGroup>
 
     <ItemGroup>

diff --git a/Frank/Internals/WebApplication.cs b/Frank/Internals/WebApplication.cs
@@ -11,8 +11,10 @@ namespace Frank.Internals
     internal class WebApplication : IWebApplication
     {
         private readonly IServer _server;
-        private readonly IRequestRouter _requestRouter;
         private readonly List<Exception> _exceptions = new List<Exception>();
+        private readonly Action<IRouteConfigurer, object> _onRequest;
+        private readonly Func<object> _onBefore;
+        private readonly Action<object> _onAfter;
 
         internal interface IRequestRouter
         {
@@ -23,10 +25,16 @@ Request request
             );
         }
 
-        public WebApplication(IServer server, IRequestRouter requestRouter)
+        public WebApplication(
+            IServer server, 
+            Action<IRouteConfigurer, object> onRequest, 
+            Func<object> onBefore,
+            Action<object> onAfter)
         {
             _server = server;
-            _requestRouter = requestRouter;
+            _onRequest = onRequest;
+            _onBefore = onBefore;
+            _onAfter = onAfter;
         }
 
         public void Start()
@@ -37,11 +45,15 @@ public void Start()
 
         private void ProcessRequest(Request request, IResponseBuffer responseBuffer)
         {
+            var context = _onBefore();
+            var router = new RequestRouter();
+            _onRequest(router, context);
+
             try
             {
-                if (_requestRouter.CanRoute(request.Path))
+                if (router.CanRoute(request.Path))
                 {
-                    var actualResponse = _requestRouter.Route(request);
+                    var actualResponse = router.Route(request);
                     responseBuffer.SetContentsOfBufferTo(actualResponse);
                 }
                 else
@@ -63,19 +75,20 @@ private void ProcessRequest(Request request, IResponseBuffer responseBuffer)
             finally
             {
                 responseBuffer.Flush();
+                _onAfter(context);
             }
         }
 
         public void Stop()
         {
+            _server.Stop();
+
             if (_exceptions.Any())
             {
                 var exception = new Exception();
                 exception.Data.Add("Exceptions", _exceptions);
                 throw exception;
             }
-
-            _server.Stop();
         }
     }
 }