feat(serve-static): support absolute path (#257)

* feat(serve-static): support absolute path

* add ci-windows

* fix the formats

* fix the jest path

* support Windows

* test support Windows

* fix the logic

* correct handling paths for Windows

* typo

* update README

* simplify the implementation

* format

* fixed file pathes in the test

* resolve if both `root` and `path` set

Co-authored-by: Taku Amano <[email protected]>

* resolve root when initialize the app

Co-authored-by: Taku Amano <[email protected]>

* Currect the behavior if root is set and path is `/favicon.ico`

---------

Co-authored-by: Taku Amano <[email protected]>

Author: yusukebe

.github/workflows/ci.yml

@@ -29,3 +29,15 @@ jobs:
       - run: bun run lint
       - run: bun run build
       - run: bun run test
+
+  ci-windows:
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22.x
+      - uses: oven-sh/setup-bun@v2
+      - run: bun install
+      - run: bun run test

README.md

@@ -168,7 +168,7 @@ import { serveStatic } from '@hono/node-server/serve-static'
 app.use('/static/*', serveStatic({ root: './' }))
 ```
 
-Note that `root` must be _relative_ to the current working directory from which the app was started. Absolute paths are not supported.
+If using a relative path, `root` will be relative to the current working directory from which the app was started.
 
 This can cause confusion when running your application locally.
 

package.json

@@ -54,7 +54,7 @@
     }
   },
   "scripts": {
-    "test": "node --expose-gc ./node_modules/.bin/jest",
+    "test": "node --expose-gc node_modules/jest/bin/jest.js",
     "build": "tsup --external hono",
     "watch": "tsup --watch",
     "postbuild": "publint",
@@ -99,4 +99,4 @@
   "peerDependencies": {
     "hono": "^4"
   }
-}
+}

src/serve-static.ts

@@ -1,8 +1,8 @@
 import type { Context, Env, MiddlewareHandler } from 'hono'
-import { getFilePath, getFilePathWithoutDefaultDocument } from 'hono/utils/filepath'
 import { getMimeType } from 'hono/utils/mime'
-import { createReadStream, lstatSync } from 'node:fs'
 import type { ReadStream, Stats } from 'node:fs'
+import { createReadStream, lstatSync } from 'node:fs'
+import { join, resolve } from 'node:path'
 
 export type ServeStaticOptions<E extends Env = Env> = {
   /**
@@ -44,10 +44,6 @@ const createStreamBody = (stream: ReadStream) => {
   return body
 }
 
-const addCurrentDirPrefix = (path: string) => {
-  return `./${path}`
-}
-
 const getStats = (path: string) => {
   let stats: Stats | undefined
   try {
@@ -60,6 +56,9 @@ const getStats = (path: string) => {
 export const serveStatic = <E extends Env = any>(
   options: ServeStaticOptions<E> = { root: '' }
 ): MiddlewareHandler<E> => {
+  const root = resolve(options.root || '.')
+  const optionPath = options.path
+
   return async (c, next) => {
     // Do nothing if Response is already set
     if (c.finalized) {
@@ -69,35 +68,40 @@ export const serveStatic = <E extends Env = any>(
     let filename: string
 
     try {
-      filename = options.path ?? decodeURIComponent(c.req.path)
+      const rawPath = optionPath ?? c.req.path
+      // Prevent encoded path traversal attacks
+      if (!optionPath) {
+        const decodedPath = decodeURIComponent(rawPath)
+        if (decodedPath.includes('..')) {
+          await options.onNotFound?.(rawPath, c)
+          return next()
+        }
+      }
+      filename = optionPath ?? decodeURIComponent(c.req.path)
     } catch {
       await options.onNotFound?.(c.req.path, c)
       return next()
     }
 
-    let path = getFilePathWithoutDefaultDocument({
-      filename: options.rewriteRequestPath ? options.rewriteRequestPath(filename, c) : filename,
-      root: options.root,
-    })
+    const requestPath = options.rewriteRequestPath
+      ? options.rewriteRequestPath(filename, c)
+      : filename
 
-    if (path) {
-      path = addCurrentDirPrefix(path)
-    } else {
-      return next()
-    }
+    let path = optionPath
+      ? options.root
+        ? resolve(join(root, optionPath))
+        : optionPath
+      : resolve(join(root, requestPath))
 
     let stats = getStats(path)
 
     if (stats && stats.isDirectory()) {
-      path = getFilePath({
-        filename: options.rewriteRequestPath ? options.rewriteRequestPath(filename, c) : filename,
-        root: options.root,
-        defaultDocument: options.index ?? 'index.html',
-      })
+      const indexFile = options.index ?? 'index.html'
+      path = resolve(join(path, indexFile))
 
-      if (path) {
-        path = addCurrentDirPrefix(path)
-      } else {
+      // Security check: prevent path traversal attacks
+      if (!optionPath && !path.startsWith(root)) {
+        await options.onNotFound?.(path, c)
         return next()
       }
 

test/serve-static.test.ts

@@ -1,6 +1,6 @@
 import { Hono } from 'hono'
-
 import request from 'supertest'
+import path from 'node:path'
 import { serveStatic } from './../src/serve-static'
 import { createAdaptorServer } from './../src/server'
 
@@ -68,7 +68,9 @@ describe('Serve Static Middleware', () => {
     expect(res.status).toBe(200)
     expect(res.text).toBe('<h1>Hello Hono</h1>')
     expect(res.headers['content-type']).toBe('text/html; charset=utf-8')
-    expect(res.headers['x-custom']).toBe('Found the file at ./test/assets/static/index.html')
+    expect(res.headers['x-custom']).toMatch(
+      /Found the file at .*[\/\\]test[\/\\]assets[\/\\]static[\/\\]index\.html$/
+    )
   })
 
   it('Should return hono.html', async () => {
@@ -167,8 +169,8 @@ describe('Serve Static Middleware', () => {
   it('Should handle the `onNotFound` option', async () => {
     const res = await request(server).get('/on-not-found/foo.txt')
     expect(res.status).toBe(404)
-    expect(notFoundMessage).toBe(
-      './not-found/on-not-found/foo.txt is not found, request to /on-not-found/foo.txt'
+    expect(notFoundMessage).toMatch(
+      /.*[\/\\]not-found[\/\\]on-not-found[\/\\]foo\.txt is not found, request to \/on-not-found\/foo\.txt$/
     )
   })
 
@@ -226,4 +228,95 @@ describe('Serve Static Middleware', () => {
     expect(res.headers['vary']).toBeUndefined()
     expect(res.text).toBe('Hello Not Compressed')
   })
+
+  describe('Absolute path', () => {
+    const rootPaths = [
+      path.join(__dirname, 'assets'),
+      __dirname + path.sep + '..' + path.sep + 'test' + path.sep + 'assets',
+    ]
+    rootPaths.forEach((root) => {
+      describe(root, () => {
+        const app = new Hono()
+        const server = createAdaptorServer(app)
+        app.use('/static/*', serveStatic({ root }))
+        app.use('/favicon.ico', serveStatic({ path: root + path.sep + 'favicon.ico' }))
+
+        it('Should return index.html', async () => {
+          const res = await request(server).get('/static')
+          expect(res.status).toBe(200)
+          expect(res.headers['content-type']).toBe('text/html; charset=utf-8')
+          expect(res.text).toBe('<h1>Hello Hono</h1>')
+        })
+
+        it('Should return correct headers and data for text', async () => {
+          const res = await request(server).get('/static/plain.txt')
+          expect(res.status).toBe(200)
+          expect(res.headers['content-type']).toBe('text/plain; charset=utf-8')
+          expect(res.text).toBe('This is plain.txt')
+        })
+        it('Should return correct headers for icons', async () => {
+          const res = await request(server).get('/favicon.ico')
+          expect(res.status).toBe(200)
+          expect(res.headers['content-type']).toBe('image/x-icon')
+        })
+      })
+    })
+  })
+
+  describe('Root and path combination tests', () => {
+    const rootPaths = [
+      path.join(__dirname, 'assets'),
+      path.join(__dirname, 'assets'),
+      __dirname + path.sep + '..' + path.sep + 'test' + path.sep + 'assets',
+    ]
+    const optionPaths = ['favicon.ico', '/favicon.ico']
+    rootPaths.forEach((root) => {
+      optionPaths.forEach((optionPath) => {
+        describe(`${root} + ${optionPath}`, () => {
+          const app = new Hono()
+          const server = createAdaptorServer(app)
+
+          app.use(
+            '/favicon.ico',
+            serveStatic({
+              root,
+              path: optionPath,
+            })
+          )
+
+          it('Should return 200 response if both root and path set', async () => {
+            const res = await request(server).get('/favicon.ico')
+            expect(res.status).toBe(200)
+            expect(res.headers['content-type']).toBe('image/x-icon')
+          })
+        })
+      })
+    })
+  })
+
+  describe('Security tests', () => {
+    const app = new Hono()
+    const server = createAdaptorServer(app)
+    app.use('/static/*', serveStatic({ root: './test/assets' }))
+
+    it('Should prevent path traversal attacks with double dots', async () => {
+      const res = await request(server).get('/static/../secret.txt')
+      expect(res.status).toBe(404)
+    })
+
+    it('Should prevent path traversal attacks with multiple levels', async () => {
+      const res = await request(server).get('/static/../../package.json')
+      expect(res.status).toBe(404)
+    })
+
+    it('Should prevent path traversal attacks with mixed separators', async () => {
+      const res = await request(server).get('/static/..\\..\\package.json')
+      expect(res.status).toBe(404)
+    })
+
+    it('Should prevent path traversal attacks with encoded dots', async () => {
+      const res = await request(server).get('/static/%2e%2e%2fsecret.txt')
+      expect(res.status).toBe(404)
+    })
+  })
 })