# model

- feed:
  - title

    rdf>channel>title (rss 0.90)
    rdf>channel>title (rss 1.0)
    rss>channel>title (rss 0.91 netscape)
    rss>channel>title (rss 0.91 userland)
    rss>channel>title (rss 2.0)
    feed>title        (atom 1.0)

  - site_url

    rdf>channel>link (rss 0.90)
    rdf>channel>link (rss 1.0)
    rss>channel>link (rss 0.91 netscape)
    rss>channel>link (rss 0.91 userland)
    rss>channel>link (rss 2.0)
    feed>link        (atom 1.0)

- item:
  - guid

    rss>channel>guid (rss 2.0)
    feed>entry>id    (atom 1.0)

  - date

    rdf>item>dc:date     (rss 1.0)
    rss>channel>pubDate  (rss 2.0)
    feed>entry>updated   (atom 1.0)
    feed>entry>published (atom 1.0)

  - url

    rdf>item>link                  (rss 0.90)
    rdf>item>link                  (rss 1.0)
    rss>item>link                  (rss 0.91 netscape)
    rss>item>link                  (rss 0.91 userland)
    feed>entry>link[rel=alternate] (atom 1.0)

  - title

    rdf>item>title   (rss 0.90)
    rdf>item>title   (rss 1.0)
    rss>item>title   (rss 0.91 netscape)
    rss>item>title   (rss 0.91 userland)
    feed>entry>title (atom 1.0

  - content

    rss>item>description     (rss 0.91 netscape)
    rss>item>description     (rss 2.0)
    rdf>item>description     (rss 1.0)
    rdf>item>content:encoded (rss 1.0)
    feed>entry>content       (atom 1.0)

  - image_url

    feed>entry>enclosure[rel='image/*'] (atom 1.0) ???

  - podcast_url

    rss>item>enclosure attr(url)        (rss 2.0)
    feed>entry>enclosure[rel='audio/*'] (atom 1.0) ???

# specs

- rss
  https://en.wikipedia.org/wiki/RSS
  - 0.90:
    https://www.rssboard.org/rss-0-9-0
    https://web.archive.org/web/20001208063100/http://my.netscape.com/publish/help/quickstart.html
  - 0.91 (netscape)
    https://www.rssboard.org/rss-0-9-1-netscape
  - 0.91 (userland)
    https://www.rssboard.org/rss-0-9-1
  - 0.92
    https://www.rssboard.org/rss-0-9-2
    by userland, no significant changes from 0.91
  - 0.93 (withdrawn)
    http://backend.userland.com/rss093
  - 0.94 (withdrawn)
  - 1.0
    https://web.resource.org/rss/1.0/
    https://web.archive.org/web/20021014094554/https://web.resource.org/rss/1.0/spec
    reintroduced rdf from 0.90, added dublincore namespaces etc
    namespaces:
        content: http://purl.org/rss/1.0/modules/content/
        dc: http://purl.org/dc/elements/1.1/
  - 2.0
    https://cyber.harvard.edu/rss/rss.html
    https://www.rssboard.org/rss-2-0

- atom
  https://en.wikipedia.org/wiki/Atom_(Web_standard)
  - 0.3
    https://support.google.com/merchants/answer/160598?hl=en
    http://web.archive.org/web/20060811235523/http://www.mnot.net/drafts/draft-nottingham-atom-format-02.html
  - 1.0
    https://tools.ietf.org/html/rfc4287
    https://validator.w3.org/feed/docs/atom.html

- json
  https://en.wikipedia.org/wiki/JSON_Feed
  - 1.0
    https://jsonfeed.org/version/1
  - 1.1
    https://jsonfeed.org/version/1.1

# parsers

https://feedparser.readthedocs.io/en/latest/
https://github.com/mmcdole/gofeed
https://github.com/miniflux/v2/tree/2.0.28/reader/
https://github.com/Ranchero-Software/RSParser
https://github.com/feederco/feeder-parser