fileserver: Only set Etag if not already set (fix #5546) (#5547)

Charles Duffy committed May 20, 2023 at 18:21 UTC 2615c9c52417d6ac01a56841b4684400b33f7db1

1 file changed +12 -4

modules/caddyhttp/fileserver/staticfiles.go

+12 -4

@@ -356,7 +356,9 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

356 }

357

358 var file fs.File

359 - var etag string

359 +

360 + // etag is usually unset, but if the user knows what they're doing, let them override it

361 + etag := w.Header().Get("Etag")

362

363 // check for precompressed files

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

@@ -388,7 +390,9 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

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

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

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

391 - etag = calculateEtag(compressedInfo)

393 + if etag == "" {

394 + etag = calculateEtag(compressedInfo)

395 + }

396

397 break

398 }

@@ -408,7 +412,9 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

412 }

413 defer file.Close()

414

411 - etag = calculateEtag(info)

415 + if etag == "" {

416 + etag = calculateEtag(info)

417 + }

418 }

419

420 // at this point, we're serving a file; Go std lib supports only

@@ -421,7 +427,9 @@ func (fsrv *FileServer) ServeHTTP(w http.ResponseWriter, r *http.Request, next c

427

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

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

424 - w.Header().Set("Etag", etag)

430 + if etag != "" {

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

432 + }

433

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

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