[Feature Request] Allow filter rules based on specific tag

[garritfra]

As a user, I want to be able to add a filter rule to a feed based on a specific xml tag. Currently, filtering is only possible on the title.

Concrete example

Considering a feed that has these entries:

<item>
    <title>My second post</title>
    <link>https://example.com/2</link>
    <description>Some content</description>
    <author>Foo Bar</author>
    <category>dev-blogs</category>
    <pubDate>Tue, 05 Jan 2021 01:50:00 GMT</pubDate>
</item>
<item>
    <title>My first post</title>
    <link>https://example.com/1</link>
    <description>Some more content</description>
    <author>Bar Baz</author>
    <category>news</category>
    <pubDate>Sun, 03 Jan 2021 11:00:00 GMT</pubDate>
</item>

I want to be able to only subscribe to entries marked with the category "dev-blogs".

Possible solution

Add the possibility to specify tags in Keep/Block rules. If the rule is a tag (regex/raw character parsing?), query the entire entry. If not, continue as previously implemented, by just querying the title.

Resources

This feature could be implemented here: https://github.com/miniflux/v2/blob/de7a61309878e335fe99c7afbbe6a40cc097b0ae/reader/processor/processor.go#L86

Context

I stumbled upon this issue when I wanted to subscribe to the dev-blogs of a game. The authors only have a single rss feed for all their content.

[garritfra]

Fiddling around with this, I found that it's not as easy as I expected. In order to query non-standard attributes (like category), the raw entry would need to be stored. Another way would be to add an "extra tags" field, that itself is a key-value map.

Is there a simpler way to query ever field in the original entry?

[JKingweb]

For what it's worth, having anticipated the usefulness of this for The Guardian's rather large news feed in my own (forthcoming) independent implementation of Miniflux's API, I simply had rules try to match against the title, and in the absence of a match, each category name until a match is found. So, a keep rule of ^dev-blog$ would suffice.

The downside to this is that since Miniflux doesn't actually expose RSS/Atom categories, it might be confusing for users. I'd be keen to discuss the best, least confusing way to expose such a feature.

[x0tester0x]

Since the parser for the from Feeds (RSS, Atom and JSON) is already merged an implemented, when and how can I use this in the block or keep rules?

[x0tester0x]

Please implement this and update the Documentation.

[privatmamtora]

This was implemented here: #2526 Just documentation needs to be updated

[shanewstone]

This was implemented here: #2526 Just documentation needs to be updated

Please correct me if I am mistaken, but that PR only addresses global filter rules. The request here is for fields used in filter rules applied to individual feeds. The fields used to filter within specific tags (e.g., EntryTitle, EntryContent) cannot be used in a feed's keep or block rules, only in the global filter rules.