net/http: set/override Content-Length for encoded range requests
Currently, http.ServeContent returns invalid Content-Length header if:
* Request is a range request.
* Content is encoded (e.g., gzip compressed).
* Content-Length of the encoded content has been set before calling
http.ServeContent, as suggested in https://github.com/golang/go/issues/19420.
Example:
w.Header().Set("Content-Type", "application/json")
w.Header().Set("Content-Length", strconv.Itoa(len(compressedJsonBody)))
w.Header().Set("Content-Encoding", "gzip")
w.Header().Set("Etag", etag)
http.ServeContent(
w, req, "", time.Time{},
bytes.NewReader(compressedJsonBody),
)
The issue is that http.ServeContent currently sees Content-Length as
something optional when Content-Encoding is set, but that is a problem
with range request which can send a payload of different size. So this
reverts https://go.dev/cl/
4538111 and makes Content-Length be set
always to the number of bytes which will actually be send (both for
range and non-range requests).
Without this fix, this is an example response:
HTTP/1.1 206 Partial Content
Accept-Ranges: bytes
Content-Encoding: gzip
Content-Length: 351
Content-Range: bytes 100-350/351
Content-Type: application/json; charset=UTF-8
Etag: "amCTP_vgT5PQt5OsAEI7NFJ6Hx1UfEpR5nIaYEInfOA"
Date: Sat, 29 Jan 2022 14:42:15 GMT
As you see, Content-Length is invalid and should be 251.
Change-Id: I4d2ea3a8489a115f92ef1f7e98250d555b47a94e
GitHub-Last-Rev:
3aff9126f5d62725c7d539df2d0eb2b860a84ca6
GitHub-Pull-Request: golang/go#50904
Reviewed-on: https://go-review.googlesource.com/c/go/+/381956
Reviewed-by: Damien Neil <dneil@google.com>
Run-TryBot: t hepudds <thepudds1460@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>