Artifact: support downloading artifacts with CJK characters in their name (#2341)

* Artifact: support downloading artifacts with CJK characters in their name

* Fix some linting/PR comments

* One more linting fix

packages/artifact/RELEASES.md

@@ -1,5 +1,9 @@
 # @actions/artifact Releases
 
+## 6.2.1
+
+- Support the RFC 5987 `filename*` field in the `content-disposition` header. This allows us to correctly download files and artifacts with Chinese/Japanese/Korean (among other) characters in their name.
+
 ## 6.2.0
 
 - Support uploading single un-archived files (not zipped). Direct uploads are only supported for artifacts version 7+ (based on the major version of `actions/upload-artifact`). Callers must pass the `skipArchive` option to `uploadArtifact`. Only single files can be uploaded at a time right now. Default behavior should remain unchanged if `skipArchive = false`. When `skipArchive = true`, the name of the file is used as the name of the artifact for consistency with the downloads: you upload `artifact.txt`, you download `artifact.txt`.

packages/artifact/__tests__/download-artifact.test.ts

@@ -977,5 +977,125 @@ describe('download-artifact', () => {
       )
       expect(fs.existsSync(maliciousPath)).toBe(false)
     })
+
+    it('should correctly handle Content-Disposition with filename* parameter (RFC 5987)', async () => {
+      const rawFileContent = 'content with rfc5987 encoding'
+      const expectedFileName = '报告-土-x.txt'
+      const asciiFileName = '__-_-x.txt'
+
+      const mockGetRfc5987File = jest.fn(() => {
+        const message = new http.IncomingMessage(new net.Socket())
+        message.statusCode = 200
+        message.headers['content-type'] = 'text/plain'
+        // Server sends both: filename with _ fallbacks, filename* with UTF-8 encoding
+        message.headers['content-disposition'] =
+          `attachment; filename="${asciiFileName}"; filename*=UTF-8''${encodeURIComponent(expectedFileName)}`
+        message.push(Buffer.from(rawFileContent, 'utf8'))
+        message.push(null)
+        return {
+          message
+        }
+      })
+
+      const mockHttpClient = (HttpClient as jest.Mock).mockImplementation(
+        () => {
+          return {
+            get: mockGetRfc5987File
+          }
+        }
+      )
+
+      await streamExtractExternal(
+        fixtures.blobStorageUrl,
+        fixtures.workspaceDir
+      )
+
+      expect(mockHttpClient).toHaveBeenCalledWith(getUserAgentString())
+      const savedFilePath = path.join(fixtures.workspaceDir, expectedFileName)
+      expect(fs.existsSync(savedFilePath)).toBe(true)
+      expect(fs.readFileSync(savedFilePath, 'utf8')).toBe(rawFileContent)
+    })
+
+    it('should handle zip artifacts with Chinese characters in the artifact name', async () => {
+      // Simulate Azure Blob Storage URL with rscd containing Chinese filename
+      const chineseArtifactName = 'probe-土-x'
+      const asciiArtifactName = 'probe-_-x'
+      const blobUrlWithChineseName = `https://blob-storage.local/artifact.zip?rscd=${encodeURIComponent(`attachment; filename="${asciiArtifactName}.zip"; filename*=UTF-8''${encodeURIComponent(`${chineseArtifactName}.zip`)}`)}&rsct=application%2Fzip&sig=abc123`
+
+      const mockGetZip = jest.fn(() => {
+        const message = new http.IncomingMessage(new net.Socket())
+        message.statusCode = 200
+        message.headers['content-type'] = 'application/zip'
+        message.headers['content-disposition'] =
+          `attachment; filename="${asciiArtifactName}.zip"; filename*=UTF-8''${encodeURIComponent(`${chineseArtifactName}.zip`)}`
+        message.push(fs.readFileSync(fixtures.exampleArtifact.path))
+        message.push(null)
+        return {
+          message
+        }
+      })
+
+      const mockHttpClient = (HttpClient as jest.Mock).mockImplementation(
+        () => {
+          return {
+            get: mockGetZip
+          }
+        }
+      )
+
+      await streamExtractExternal(blobUrlWithChineseName, fixtures.workspaceDir)
+
+      expect(mockHttpClient).toHaveBeenCalledWith(getUserAgentString())
+      // Zip should be extracted normally regardless of Chinese artifact name
+      await expectExtractedArchive(fixtures.workspaceDir)
+    })
+
+    it.each([
+      ['土', '_'], // U+571F - known to cause 400 errors
+      ['日', '_'], // U+65E5 - reported to work fine
+      ['中文测试', '____'], // multiple Chinese characters
+      ['文件-2026年', '__-2026_'], // mixed Chinese and numbers
+      ['データ', '___'], // Japanese katakana
+      ['테스트', '___'] // Korean characters
+    ])(
+      'should prefer filename* over filename for non-ASCII character %s (%s)',
+      async (chars, asciiReplacement) => {
+        const rawFileContent = `content for ${chars}`
+        const expectedFileName = `artifact-${chars}.txt`
+        const asciiFileName = `artifact-${asciiReplacement}.txt`
+
+        const mockGetFile = jest.fn(() => {
+          const message = new http.IncomingMessage(new net.Socket())
+          message.statusCode = 200
+          message.headers['content-type'] = 'text/plain'
+          // Server sends filename with _ replacing non-ASCII, filename* with proper encoding
+          message.headers['content-disposition'] =
+            `attachment; filename="${asciiFileName}"; filename*=UTF-8''${encodeURIComponent(expectedFileName)}`
+          message.push(Buffer.from(rawFileContent, 'utf8'))
+          message.push(null)
+          return {
+            message
+          }
+        })
+
+        const mockHttpClient = (HttpClient as jest.Mock).mockImplementation(
+          () => {
+            return {
+              get: mockGetFile
+            }
+          }
+        )
+
+        await streamExtractExternal(
+          fixtures.blobStorageUrl,
+          fixtures.workspaceDir
+        )
+
+        expect(mockHttpClient).toHaveBeenCalledWith(getUserAgentString())
+        const savedFilePath = path.join(fixtures.workspaceDir, expectedFileName)
+        expect(fs.existsSync(savedFilePath)).toBe(true)
+        expect(fs.readFileSync(savedFilePath, 'utf8')).toBe(rawFileContent)
+      }
+    )
   })
 })

packages/artifact/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/artifact",
-  "version": "6.2.0",
+  "version": "6.2.1",
   "preview": true,
   "description": "Actions artifact lib",
   "keywords": [

packages/artifact/src/internal/download/download-artifact.ts

@@ -93,16 +93,22 @@ export async function streamExtractExternal(
     urlEndsWithZip
 
   // Extract filename from Content-Disposition header
+  // Prefer filename* (RFC 5987) which supports UTF-8 encoded filenames,
+  // fall back to filename which may contain ASCII-only replacements
   const contentDisposition =
     response.message.headers['content-disposition'] || ''
   let fileName = 'artifact'
-  const filenameMatch = contentDisposition.match(
+  const filenameStar = contentDisposition.match(
-    /filename\*?=['"]?(?:UTF-\d['"]*)?([^;\r\n"']*)['"]?/i
+    /filename\*\s*=\s*UTF-8''([^;\r\n]*)/i
   )
-  if (filenameMatch && filenameMatch[1]) {
+  const filenamePlain = contentDisposition.match(
+    /(?<!\*)filename\s*=\s*['"]?([^;\r\n"']*)['"]?/i
+  )
+  const rawName = filenameStar?.[1] || filenamePlain?.[1]
+  if (rawName) {
     // Sanitize fileName to prevent path traversal attacks
     // Use path.basename to extract only the filename component
-    fileName = path.basename(decodeURIComponent(filenameMatch[1].trim()))
+    fileName = path.basename(decodeURIComponent(rawName.trim()))
   }
 
   core.debug(