Hello!

On Tue, Jun 20, 2017 at 10:39:44AM +0800, 胡聪 (hucc) wrote:

> Hi,
>
> >416 will be returned when the request has no Range HEADER and the target file is
> >empty. Apparently, it does not conform to the HTTP protocol. Empty file seems
> >inevitable in the CDN service where Nginx is heavily used.
> >
> ># HG changeset patch
> ># User hucongcong <hucong.c@foxmail.com>
> ># Date 1497892764 -28800
> ># Tue Jun 20 01:19:24 2017 +0800
> ># Node ID 79d38b2d27d4eb92395cf1ff43bbfe23498bc69a
> ># Parent d1816a2696de8c2faa1cd913a151e5f62a8620f3
> >Slice filter: support for empty file.
>
> The following modifications may be more appropriate.
>
> # HG changeset patch
> # User hucongcong <hucong.c@foxmail.com>
> # Date 1497926137 -28800
> # Tue Jun 20 10:35:37 2017 +0800
> # Node ID e42abb7e28c4f0dd3d66cb81aa2623e7fae8b4da
> # Parent a39bc74873faf9e5bea616561b43f6ecc55229f9
> Slice filter: support for empty file.
>
> diff -r a39bc74873fa -r e42abb7e28c4 src/http/modules/ngx_http_slice_filter_module.c
> --- a/src/http/modules/ngx_http_slice_filter_module.c Mon Jun 19 14:25:42 2017 +0300
> +++ b/src/http/modules/ngx_http_slice_filter_module.c Tue Jun 20 10:35:37 2017 +0800
> @@ -114,7 +114,21 @@ ngx_http_slice_header_filter(ngx_http_re
> }
>
> if (r->headers_out.status != NGX_HTTP_PARTIAL_CONTENT) {
> +
> if (r == r->main) {
> + if (r->headers_in.range == NULL
> + && r->headers_out.status == NGX_HTTP_RANGE_NOT_SATISFIABLE)
> + {
> + r->header_only = 1;
> + ngx_str_null(&r->headers_out.content_type);
> +
> + r->headers_out.status = NGX_HTTP_OK;
> + r->headers_out.status_line.len = 0;
> + r->headers_out.content_length_n = 0;
> + r->headers_out.content_range->hash = 0;
> + r->headers_out.content_range = NULL;
> + }
> +
> ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module);
> return ngx_http_next_header_filter(r);
> }

Returning the 416 response with some headers deleted and status
code changed to 200 doesn't look like a safe solution.

On the other hand, changing nginx's range filter to allow range
requests to 0-byte files should make this unneeded. I've reopened
ticket #1031 which is about range requests to 0-byte files, see
https://trac.nginx.org/nginx/ticket/1031.

--
Maxim Dounin
http://nginx.org/
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