fix(trailing-slash): handle HEAD request in trailing slash middleware

src/middleware/trailing-slash/index.test.ts

@@ -2,11 +2,8 @@ import { Hono } from '../../hono'
 import { appendTrailingSlash, trimTrailingSlash } from '.'
 
 describe('Resolve trailing slash', () => {
-  let app: Hono
-
-  it('Trim', async () => {
-    app = new Hono({ strict: true })
-
+  describe('trimTrailingSlash middleware', () => {
+    const app = new Hono({ strict: true })
     app.use('*', trimTrailingSlash())
 
     app.get('/', async (c) => {
@@ -16,33 +13,82 @@ describe('Resolve trailing slash', () => {
       return c.text('ok')
     })
 
-    let resp: Response, loc: URL
+    it('should handle GET request for root path correctly', async () => {
+      const resp = await app.request('/')
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
 
-    resp = await app.request('/')
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(200)
+    it('should handle GET request for path without trailing slash correctly', async () => {
+      const resp = await app.request('/the/example/endpoint/without/trailing/slash')
 
-    resp = await app.request('/the/example/endpoint/without/trailing/slash')
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(200)
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
 
-    resp = await app.request('/the/example/endpoint/without/trailing/slash/')
-    loc = new URL(resp.headers.get('location')!)
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(301)
-    expect(loc.pathname).toBe('/the/example/endpoint/without/trailing/slash')
+    it('should handle GET request for path with trailing slash correctly', async () => {
+      const resp = await app.request('/the/example/endpoint/without/trailing/slash/')
+      const loc = new URL(resp.headers.get('location')!)
 
-    resp = await app.request('/the/example/endpoint/without/trailing/slash/?exampleParam=1')
-    loc = new URL(resp.headers.get('location')!)
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(301)
-    expect(loc.pathname).toBe('/the/example/endpoint/without/trailing/slash')
-    expect(loc.searchParams.get('exampleParam')).toBe('1')
-  })
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/without/trailing/slash')
+    })
+
+    it('should preserve query parameters when redirecting', async () => {
+      const resp = await app.request('/the/example/endpoint/without/trailing/slash/?exampleParam=1')
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/without/trailing/slash')
+      expect(loc.searchParams.get('exampleParam')).toBe('1')
+    })
+
+    it('should handle HEAD request for root path correctly', async () => {
+      const resp = await app.request('/', { method: 'HEAD' })
 
-  it('Append', async () => {
-    app = new Hono({ strict: true })
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
 
+    it('should handle HEAD request for path without trailing slash correctly', async () => {
+      const resp = await app.request('/the/example/endpoint/without/trailing/slash', {
+        method: 'HEAD',
+      })
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
+
+    it('should handle HEAD request for path with trailing slash correctly', async () => {
+      const resp = await app.request('/the/example/endpoint/without/trailing/slash/', {
+        method: 'HEAD',
+      })
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/without/trailing/slash')
+    })
+
+    it('should preserve query parameters when redirecting HEAD requests', async () => {
+      const resp = await app.request(
+        '/the/example/endpoint/without/trailing/slash/?exampleParam=1',
+        { method: 'HEAD' }
+      )
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/without/trailing/slash')
+      expect(loc.searchParams.get('exampleParam')).toBe('1')
+    })
+  })
+
+  describe('appendTrailingSlash middleware', () => {
+    const app = new Hono({ strict: true })
     app.use('*', appendTrailingSlash())
 
     app.get('/', async (c) => {
@@ -55,31 +101,90 @@ describe('Resolve trailing slash', () => {
       return c.text('ok')
     })
 
-    let resp: Response, loc: URL
+    it('should handle GET request for root path correctly', async () => {
+      const resp = await app.request('/')
 
-    resp = await app.request('/')
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(200)
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
 
-    resp = await app.request('/the/example/simulate/a.file')
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(200)
+    it('should handle GET request for file-like paths correctly', async () => {
+      const resp = await app.request('/the/example/simulate/a.file')
 
-    resp = await app.request('/the/example/endpoint/with/trailing/slash/')
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(200)
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
 
-    resp = await app.request('/the/example/endpoint/with/trailing/slash')
-    loc = new URL(resp.headers.get('location')!)
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(301)
-    expect(loc.pathname).toBe('/the/example/endpoint/with/trailing/slash/')
+    it('should handle GET request for path with trailing slash correctly', async () => {
+      const resp = await app.request('/the/example/endpoint/with/trailing/slash/')
 
-    resp = await app.request('/the/example/endpoint/with/trailing/slash?exampleParam=1')
-    loc = new URL(resp.headers.get('location')!)
-    expect(resp).not.toBeNull()
-    expect(resp.status).toBe(301)
-    expect(loc.pathname).toBe('/the/example/endpoint/with/trailing/slash/')
-    expect(loc.searchParams.get('exampleParam')).toBe('1')
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
+
+    it('should redirect path without trailing slash to one with it', async () => {
+      const resp = await app.request('/the/example/endpoint/with/trailing/slash')
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/with/trailing/slash/')
+    })
+
+    it('should preserve query parameters when redirecting', async () => {
+      const resp = await app.request('/the/example/endpoint/with/trailing/slash?exampleParam=1')
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/with/trailing/slash/')
+      expect(loc.searchParams.get('exampleParam')).toBe('1')
+    })
+
+    it('should handle HEAD request for root path correctly', async () => {
+      const resp = await app.request('/', { method: 'HEAD' })
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
+
+    it('should handle HEAD request for file-like paths correctly', async () => {
+      const resp = await app.request('/the/example/simulate/a.file', { method: 'HEAD' })
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
+
+    it('should handle HEAD request for path with trailing slash correctly', async () => {
+      const resp = await app.request('/the/example/endpoint/with/trailing/slash/', {
+        method: 'HEAD',
+      })
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(200)
+    })
+
+    it('should redirect HEAD request for path without trailing slash to one with it', async () => {
+      const resp = await app.request('/the/example/endpoint/with/trailing/slash', {
+        method: 'HEAD',
+      })
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/with/trailing/slash/')
+    })
+
+    it('should preserve query parameters when redirecting HEAD requests', async () => {
+      const resp = await app.request('/the/example/endpoint/with/trailing/slash?exampleParam=1', {
+        method: 'HEAD',
+      })
+      const loc = new URL(resp.headers.get('location')!)
+
+      expect(resp).not.toBeNull()
+      expect(resp.status).toBe(301)
+      expect(loc.pathname).toBe('/the/example/endpoint/with/trailing/slash/')
+      expect(loc.searchParams.get('exampleParam')).toBe('1')
+    })
   })
 })

src/middleware/trailing-slash/index.ts

@@ -26,7 +26,7 @@ export const trimTrailingSlash = (): MiddlewareHandler => {
 
     if (
       c.res.status === 404 &&
-      c.req.method === 'GET' &&
+      (c.req.method === 'GET' || c.req.method === 'HEAD') &&
       c.req.path !== '/' &&
       c.req.path.at(-1) === '/'
     ) {
@@ -57,7 +57,11 @@ export const appendTrailingSlash = (): MiddlewareHandler => {
   return async function appendTrailingSlash(c, next) {
     await next()
 
-    if (c.res.status === 404 && c.req.method === 'GET' && c.req.path.at(-1) !== '/') {
+    if (
+      c.res.status === 404 &&
+      (c.req.method === 'GET' || c.req.method === 'HEAD') &&
+      c.req.path.at(-1) !== '/'
+    ) {
       const url = new URL(c.req.url)
       url.pathname += '/'