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by asjo 514 days ago
rachelbythebay has a service and a series of blog posts about the technical side of this, starting at https://rachelbythebay.com/w/2024/05/27/feed/

TL;DR: readers should not poll more often than once and hour, use ETag and If-Modified-Since to determine whether to download the full feed again.

Which items you have seen previously is something the feed reader keeps track of.
2 comments
account42 512 days ago
Polling every hour is excessive and will get you temp-blocked on some sites.

It really depends on you but IMO for most feeds polling once a day is plenty.

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fire_lake 513 days ago
> Which items you have seen previously is something the feed reader keeps track of.

Is there a particular field that can be used as an identifier?

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asjo 513 days ago
Yes, the `guid` field in RSS and the `id` field in Atom.
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account42 512 days ago
A lot of readers (intentionally?) get this wrong though and show entries as new/unread if there are changes to the content.

Of course a lot of feeds also get this wrong and change the GUIDs for existing entries once in a while which results in strictly compliant readers showing you the entire feed history as new. Really annoying.

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asjo 510 days ago
My system updates¹ the entry and marks the changes in the first case. What is right and what is wrong depends on what you want, I think.

The latter is annoying, I agree.

¹ It is an NNTP interface so the article is superseded; https://feedbase.org/about/ - if you don't want to see updates, you can configure your newsreader to skip supersedes.

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