From 1bc97767559f8f1603eaf7218e9d197602b4fed0 Mon Sep 17 00:00:00 2001
From: Stevan Freeborn <65925598+StevanFreeborn@users.noreply.github.com>
Date: Sat, 24 May 2025 17:48:18 -0500
Subject: [PATCH] feat: implement injectServices middleware and useService
 helper

---
 src/index.ts        |  47 +++++++++++++-
 tests/index.spec.ts | 152 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 197 insertions(+), 2 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index c10834b..e2eb7dc 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1 +1,46 @@
-console.log("hono-netdi");
+import {
+  ServiceScope,
+  type IServiceProvider,
+  type IServiceScope,
+  type ServiceIdentifier,
+} from '@stevanfreeborn/netdi';
+
+import type { Context, MiddlewareHandler } from 'hono';
+
+const SERVICE_SCOPE_KEY = 'serviceScope';
+
+declare module 'hono' {
+  interface ContextVariableMap {
+    [SERVICE_SCOPE_KEY]?: IServiceScope;
+  }
+}
+
+export function injectServices(serviceProvider: IServiceProvider): MiddlewareHandler {
+  return async (c: Context, next: () => Promise<void>) => {
+    const scope = serviceProvider.createScope();
+
+    c.set(SERVICE_SCOPE_KEY, scope);
+
+    try {
+      await next();
+    } finally {
+      scope.dispose();
+    }
+  };
+}
+
+export function useService<T>(c: Context, serviceType: ServiceIdentifier<T>): T {
+  const scope = c.get(SERVICE_SCOPE_KEY);
+
+  if (!scope) {
+    throw new Error(
+      'Service scope not found in context. Did you add the injectServices middleware?',
+    );
+  }
+
+  if (scope instanceof ServiceScope === false) {
+    throw new Error('Service scope is not an instance of ServiceScope.');
+  }
+
+  return scope.serviceProvider.getService(serviceType);
+}
diff --git a/tests/index.spec.ts b/tests/index.spec.ts
index d63af00..ce4d4f9 100644
--- a/tests/index.spec.ts
+++ b/tests/index.spec.ts
@@ -1 +1,151 @@
-console.log("hono-netdi tests");
+import { describe, expect, test } from 'vitest';
+import { Env, Hono } from 'hono';
+import { createServiceIdentifier, IServiceScope, ServiceCollection } from '@stevanfreeborn/netdi';
+import { injectServices, useService } from '../src/index';
+import { randomUUID } from 'crypto';
+
+describe('injectServices', () => {
+  test('it should create a service scope and dispose of it after the request', async () => {
+    interface ITestService {
+      id(): string;
+    }
+
+    class TestService implements ITestService {
+      constructor() {}
+
+      public id() {
+        return randomUUID();
+      }
+    }
+
+    const serviceId = createServiceIdentifier<ITestService>();
+    const services = new ServiceCollection();
+    services.addScoped(serviceId, TestService);
+
+    const sp = services.build();
+    const app = new Hono<Env>();
+
+    app.use(injectServices(sp));
+
+    app.get('/', c => {
+      const scope = c.get('serviceScope');
+      const testService = scope!.serviceProvider.getService(serviceId);
+      return c.json({ id: testService.id() });
+    });
+
+    const res1 = await app.request('/');
+    const json1 = await res1.json();
+    const firstId = json1.id;
+
+    const res2 = await app.request('/');
+    const json2 = await res2.json();
+    const secondId = json2.id;
+
+    expect(firstId).not.toEqual(secondId);
+  });
+});
+
+describe('useService', () => {
+  test('it should throw an error if the service scope is not found in context', async () => {
+    type ITestService = object;
+    
+    const serviceId = createServiceIdentifier<ITestService>();
+    const app = new Hono<Env>();
+
+    app.get('/', c => {
+      try {
+        useService(c, serviceId);
+        return c.text('Service scope found', 200);
+      } catch {
+        return c.text('Service scope not found', 500);
+      }
+    });
+
+    const res = await app.request('/');
+
+    expect(res.status).toBe(500);
+  });
+
+  test('it should throw an error if the service scope is not an instance of ServiceScope', async () => {
+    type ITestService = object;
+    
+    const serviceId = createServiceIdentifier<ITestService>();
+    const app = new Hono<Env>();
+
+    app.get('/', c => {
+      c.set('serviceScope', {} as IServiceScope);
+      
+      try {
+        useService(c, serviceId);
+        return c.text('Service scope found', 200);
+      } catch {
+        return c.text('Service scope not found', 500);
+      }
+    });
+
+    const res = await app.request('/');
+
+    expect(res.status).toBe(500);
+  });
+
+  test('it should throw an error if the service is not registered in the service scope', async () => {
+    interface ITestService {
+      id(): string;
+    }
+
+    const serviceId = createServiceIdentifier<ITestService>();
+    const services = new ServiceCollection();
+
+    const sp = services.build();
+    const app = new Hono<Env>();
+
+    app.use(injectServices(sp));
+
+    app.get('/', c => {
+      try {
+        useService(c, serviceId);
+        return c.text('Service found', 200);
+      } catch {
+        return c.text('Service not found', 500);
+      }
+    });
+
+    const res = await app.request('/');
+
+    expect(res.status).toBe(500);
+  });
+
+
+  test('it should return the service from the service scope', async () => {
+    interface ITestService {
+      id(): string;
+    }
+
+    class TestService implements ITestService {
+      constructor() {}
+
+      public id() {
+        return 'test-id';
+      }
+    }
+
+    const serviceId = createServiceIdentifier<ITestService>();
+    const services = new ServiceCollection();
+    services.addScoped(serviceId, TestService);
+
+    const sp = services.build();
+    const app = new Hono<Env>();
+
+    app.use(injectServices(sp));
+
+    app.get('/', c => {
+      const testService = useService(c, serviceId);
+      return c.json({ id: testService.id() });
+    });
+
+    const res = await app.request('/');
+    const data = await res.json();
+
+    expect(data.id).toBe('test-id');
+  });
+});