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Re: [RFE] Improve etag handling with --etag-compare-update
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From: Aleksei via curl-users <curl-users_at_lists.haxx.se>
Date: Tue, 29 Apr 2025 07:36:38 +0300
On 2025-04-28, Daniel Stenberg wrote:
>On Mon, 28 Apr 2025, Aleksei via curl-users wrote:
>
>>I'm trying to implement a "download only if updated on a remote
>>resource" functionality with a curl script using etags.
>>
>>Currently the etag file saved with --etag-save becomes useless after
>>a single update on a remote resource.
>
>I don't understand. Can you elaborate? If the remote resource is
>indeed updated, surely it should download again and update the etag
>file?
>
> / daniel.haxx.se || https://rock-solid.curl.dev
I'm asking for "and update the etag file" part to be done by curl.
Scenario:
1) curl downloads a webpage, saving etag file in file0.etag
2) website updates a webpage (update 1)
3) curl uses "--etag-compare file0.etag" and re-downloads the page -
so far so good
4) website updates a webpage (update 2)
5) How do I check that webpage is updated now? "--etag-compare
file0.etag" will re-download even if update 2 has been downloaded
Currently I would have to add a check at #3 to save the etag in a temp
file, compare to file0.etag and copy it over if necessary - a
script-side workaround I'm trying to avoid.
Date: Tue, 29 Apr 2025 07:36:38 +0300
On 2025-04-28, Daniel Stenberg wrote:
>On Mon, 28 Apr 2025, Aleksei via curl-users wrote:
>
>>I'm trying to implement a "download only if updated on a remote
>>resource" functionality with a curl script using etags.
>>
>>Currently the etag file saved with --etag-save becomes useless after
>>a single update on a remote resource.
>
>I don't understand. Can you elaborate? If the remote resource is
>indeed updated, surely it should download again and update the etag
>file?
>
> / daniel.haxx.se || https://rock-solid.curl.dev
I'm asking for "and update the etag file" part to be done by curl.
Scenario:
1) curl downloads a webpage, saving etag file in file0.etag
2) website updates a webpage (update 1)
3) curl uses "--etag-compare file0.etag" and re-downloads the page -
so far so good
4) website updates a webpage (update 2)
5) How do I check that webpage is updated now? "--etag-compare
file0.etag" will re-download even if update 2 has been downloaded
Currently I would have to add a check at #3 to save the etag in a temp
file, compare to file0.etag and copy it over if necessary - a
script-side workaround I'm trying to avoid.
-- Unsubscribe: https://lists.haxx.se/mailman/listinfo/curl-users Etiquette: https://curl.se/mail/etiquette.htmlReceived on 2025-04-29