fix: unixfs dir redirect (#33)

* fix: check redirect trailing slash if path is empty

* test: add interop test for unixfs directory redirect

* chore: add gateway-conformance-fixtures car file

* test: add verified-fetch unit test for root directory redirect

packages/interop/src/unixfs-dir.spec.ts

@@ -26,6 +26,25 @@ describe('@helia/verified-fetch - unixfs directory', () => {
     await verifiedFetch.stop()
   })
 
+  describe('unixfs-dir-redirect', () => {
+    before(async () => {
+      await loadFixtureDataCar(controller, 'gateway-conformance-fixtures.car')
+    });
+
+    [
+      'https://example.com/ipfs/bafybeifq2rzpqnqrsdupncmkmhs3ckxxjhuvdcbvydkgvch3ms24k5lo7q',
+      'ipfs://bafybeifq2rzpqnqrsdupncmkmhs3ckxxjhuvdcbvydkgvch3ms24k5lo7q',
+      'http://example.com/ipfs/bafybeifq2rzpqnqrsdupncmkmhs3ckxxjhuvdcbvydkgvch3ms24k5lo7q'
+    ].forEach((url: string) => {
+      it(`request to unixfs directory with ${url} should return a 301 with a trailing slash`, async () => {
+        const response = await verifiedFetch(url, { redirect: 'manual' })
+        expect(response).to.be.ok()
+        expect(response.status).to.equal(301)
+        expect(response.headers.get('location')).to.equal(`${url}/`)
+      })
+    })
+  })
+
   describe('XKCD Barrel Part 1', () => {
     before(async () => {
       // This is the content of https://explore.ipld.io/#/explore/QmdmQXB2mzChmMeKY47C43LxUdg1NDJ5MWcKMKxDu7RgQm/1%20-%20Barrel%20-%20Part%201

packages/verified-fetch/src/verified-fetch.ts

@@ -299,9 +299,10 @@ export class VerifiedFetch {
     let resolvedCID = terminalElement?.cid ?? cid
     if (terminalElement?.type === 'directory') {
       const dirCid = terminalElement.cid
+      const redirectCheckNeeded = path === '' ? !resource.toString().endsWith('/') : !path.endsWith('/')
 
       // https://specs.ipfs.tech/http-gateways/path-gateway/#use-in-directory-url-normalization
-      if (path !== '' && !path.endsWith('/')) {
+      if (redirectCheckNeeded) {
         if (options?.redirect === 'error') {
           this.log('could not redirect to %s/ as redirect option was set to "error"', resource)
           throw new TypeError('Failed to fetch')

packages/verified-fetch/test/verified-fetch.spec.ts

@@ -160,6 +160,33 @@ describe('@helia/verifed-fetch', () => {
       expect(ipfsResponse.url).to.equal(`ipfs://${res.cid}/foo`)
     })
 
+    it('should return a 301 with a trailing slash when a root directory is requested without a trailing slash', async () => {
+      const finalRootFileContent = new Uint8Array([0x01, 0x02, 0x03])
+
+      const fs = unixfs(helia)
+      const res = await last(fs.addAll([{
+        path: '/index.html',
+        content: finalRootFileContent
+      }], {
+        wrapWithDirectory: true
+      }))
+
+      if (res == null) {
+        throw new Error('Import failed')
+      }
+
+      const stat = await fs.stat(res.cid)
+      expect(stat.type).to.equal('directory')
+
+      const ipfsResponse = await verifiedFetch.fetch(`https://ipfs.local/ipfs/${res.cid}`, {
+        redirect: 'manual'
+      })
+      expect(ipfsResponse).to.be.ok()
+      expect(ipfsResponse.status).to.equal(301)
+      expect(ipfsResponse.headers.get('location')).to.equal(`https://ipfs.local/ipfs/${res.cid}/`)
+      expect(ipfsResponse.url).to.equal(`https://ipfs.local/ipfs/${res.cid}`)
+    })
+
     it('should return a 301 with a trailing slash when a gateway directory is requested without a trailing slash', async () => {
       const finalRootFileContent = new Uint8Array([0x01, 0x02, 0x03])