fix(serve-static): enable in any order (#244)

Close #243

src/middleware/serve-static/index.test.ts

@@ -1,3 +1,5 @@
+import type { Context } from '../../context'
+import type { Next } from '../../hono'
 import { Hono } from '../../hono'
 import { serveStatic } from '.'
 
@@ -62,3 +64,37 @@ describe('ServeStatic Middleware', () => {
     expect(res.headers.get('Content-Type')).toBe('text/html; charset=utf-8')
   })
 })
+
+describe('With middleware', () => {
+  const app = new Hono()
+  const md1 = async (c: Context, next: Next) => {
+    await next()
+    c.res.headers.append('x-foo', 'bar')
+  }
+  const md2 = async (c: Context, next: Next) => {
+    await next()
+    c.res.headers.append('x-foo2', 'bar2')
+  }
+
+  app.use('/static/*', md1)
+  app.use('/static/*', serveStatic({ root: './assets' }))
+  app.use('/static/*', md2)
+  app.get('/static/foo', (c) => {
+    return c.text('bar')
+  })
+
+  it('Should return plain.txt with correct headers', async () => {
+    const res = await app.request('http://localhost/static/plain.txt')
+    expect(res.status).toBe(200)
+    expect(await res.text()).toBe('This is plain.txt')
+    expect(res.headers.get('Content-Type')).toBe('text/plain; charset=utf-8')
+    expect(res.headers.get('x-foo')).toBe('bar')
+    expect(res.headers.get('x-foo2')).toBe('bar2')
+  })
+
+  it('Should return 200 Response', async () => {
+    const res = await app.request('http://localhost/static/foo')
+    expect(res.status).toBe(200)
+    expect(await res.text()).toBe('bar')
+  })
+})

src/middleware/serve-static/index.ts

@@ -12,7 +12,11 @@ const DEFAULT_DOCUMENT = 'index.html'
 // This middleware is available only on Cloudflare Workers.
 export const serveStatic = (opt: Options = { root: '' }) => {
   return async (c: Context, next: Next) => {
-    await next()
+    // Do nothing if Response is already set
+    if (c.res) {
+      await next()
+    }
+
     const url = new URL(c.req.url)
 
     const path = getKVFilePath({
@@ -27,9 +31,11 @@ export const serveStatic = (opt: Options = { root: '' }) => {
       if (mimeType) {
         c.header('Content-Type', mimeType)
       }
-      c.res = c.body(content)
+      // Return Response object
+      return c.body(content)
     } else {
       console.warn(`Static file: ${path} is not found`)
+      await next()
     }
   }
 }