Re: --etag-save overwrites on status 304

On 02-Oct-23 13:17, Paul Gilmartin via curl-users wrote:
> I have been in the habit of using the same file as --etag-save
> and --etag-compare.  This sort of works.  However, in case of
> HTTP/1.1 304 Not Modified my --etag-compare is overwritt4n by
> an empty file and is ineffective for the next fetch.
>
> I have started making my --etag-save a temp file and renaming
> it only on success.  Is this the best approach?
>
> Would it be better if curl wrote to --etag-save only if an
> ETag: header appears, or do some users depend on the current
> behavior?
>
Curl should write the ETag header received with the 304.  Is the server 
sending it?

If not, it's a server bug.

Note RFC2616 REQUIRES ETag to be sent "if it would have been sent in a 
200 response to the same request".

If the server is sending it, but curl isn't writing it to the 
--etag-save, it's a curl bug.

Timothe Litt
ACM Distinguished Engineer
--------------------------
This communication may not represent the ACM or my employer's views,
if any, on the matters discussed.

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