[patch-1] Range filter: support multiple ranges.
mdounin at mdounin.ru
Thu Nov 9 14:48:24 UTC 2017
On Fri, Oct 27, 2017 at 06:50:32PM +0800, 胡聪 (hucc) wrote:
> # HG changeset patch
> # User hucongcong <hucong.c at foxmail.com>
> # Date 1509099940 -28800
> # Fri Oct 27 18:25:40 2017 +0800
> # Node ID 62c100a0d42614cd46f0719c0acb0ad914594217
> # Parent b9850d3deb277bd433a689712c40a84401443520
> Range filter: support multiple ranges.
This summary line is at least misleading.
> When multiple ranges are requested, nginx will coalesce any of the ranges
> that overlap, or that are separated by a gap that is smaller than the
> NGX_HTTP_RANGE_MULTIPART_GAP macro.
(Note that the patch also does reordering of ranges. For some
reason this is not mentioned in the commit log. There are also
other changes not mentioned in the commit log - for example, I see
ngx_http_range_t was moved to ngx_http_request.h. These are
probably do not belong to the patch at all.)
Reordering and/or coalescing ranges is not something that clients
usually expect to happen. This was widely discussed at the time
of CVE-2011-3192 vulnerability in Apache. As a result, RFC 7233
introduced the "MAY coalesce" clause. But this doesn't make
clients, especially old ones, magically prepared for this.
Moreover, this will certainly break some use cases like "request
some metadata first, and then rest of the file". So this is
certainly not a good idea to always reorder / coalesce ranges
unless this is really needed for some reason. (Or even at all,
as just returning 200 might be much more compatible with various
clients, as outlined above.)
It is also not clear what you are trying to achieve with this
patch. You may want to elaborate more on what problem you are
trying to solve, may be there are better solutions.
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