fileserver: Better fix for Etag of compressed files

Matthew Holt committed Aug 8, 2022 at 13:09 UTC 7ab61f46f0db1ee63c6c691def61ca2a9ebee332

1 file changed +13 -4

modules/caddyhttp/fileserver/staticfiles.go

+13 -4

@@ -351,6 +351,7 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

351 }

352

353 var file fs.File

354 + var etag string

355

356 // check for precompressed files

357 for _, ae := range encode.AcceptedEncodings(r, fsrv.PrecompressedOrder) {

@@ -371,13 +372,19 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

372 if caddyErr, ok := err.(caddyhttp.HandlerError); ok && caddyErr.StatusCode == http.StatusServiceUnavailable {

373 return err

374 }

375 + file = nil

376 continue

377 }

378 defer file.Close()

377 - info = compressedInfo

379 w.Header().Set("Content-Encoding", ae)

380 w.Header().Del("Accept-Ranges")

381 w.Header().Add("Vary", "Accept-Encoding")

382 +

383 + // don't assign info = compressedInfo because sidecars are kind

384 + // of transparent; however we do need to set the Etag:

385 + // https://caddy.community/t/gzipped-sidecar-file-wrong-same-etag/16793

386 + etag = calculateEtag(compressedInfo)

387 +

388 break

389 }

390

@@ -395,11 +402,13 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

402 return err // error is already structured

403 }

404 defer file.Close()

405 +

406 + etag = calculateEtag(info)

407 }

408

400 - // set the ETag - note that a conditional If-None-Match request is handled

401 - // by http.ServeContent below, which checks against this ETag value

402 - w.Header().Set("Etag", calculateEtag(info))

409 + // set the Etag - note that a conditional If-None-Match request is handled

410 + // by http.ServeContent below, which checks against this Etag value

411 + w.Header().Set("Etag", etag)

412

413 if w.Header().Get("Content-Type") == "" {

414 mtyp := mime.TypeByExtension(filepath.Ext(filename))