Opened 9 years ago

Last modified 7 years ago

#4451 new defect

Accept-Encoding parsing

Reported by: Mark Nottingham Owned by:
Priority: normal Component: avformat
Version: git-master Keywords: http
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


http.c parses the Accept-Encoding response header like this:

if (!av_strcasecmp(tag, "Accept-Ranges") &&

!strncmp(p, "bytes", 5) &&
s->seekable == -1) {

h->is_streamed = 0;

} else if (!av_strcasecmp(tag, "Transfer-Encoding") &&


This means that if the string "bytes" shows up in the header at all, it will match -- making it error-prone if a range using that sequence of characters is ever defined (e.g., "newbytes" as recently proposed on the HTTP WG mailing list).

The syntax isn't difficult to parse, it's a comma-separated list of tokens with optional whitespace (the same as several other headers):

(found by Rodger Combs on the IETF HTTP WG mailing list)

Change History (2)

comment:1 by Ridley Combs, 9 years ago

Correction: the existing implementation matches if the first 5 characters are "bytes", which means it wouldn't be compatible with a server that lists multiple allowed range units without starting with "bytes".

comment:2 by Carl Eugen Hoyos, 7 years ago

Component: undeterminedavformat
Keywords: http added
Version: unspecifiedgit-master
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