The 'iffy' XML namespace

Solely a channel level element

Contains one of the following four values:

1. Ping
2. Metadata
3. Content
4. Media

iffy:completeness describes the completeness that clients should expect of RSS item elements.

• Ping makes the least commitment. Items need not include a guid element, or any elements at all beyond RSS' requirement that at least one of title or description be present. RSS documents have completion Ping by default. Any or all items may meet the requirement for a higher completeness level, but no promises or commitment is made beyond the base specification.

• Metadata commits that each item MUST include a guid element, as well as meeting the base requirements for an RSS item.

• Content commits that each item, either inside its description tag, or via an extension such as content:encoded, includes the full content of the items it includes, suitable for independent rendering by any client capable also of resolving references to linked media externally. No limitation is placed on whether the full content is placed in a description element, in content:encoded, or in some other extension.

• Media augments Content by embedding attachments to subsidiary media inside the RSS document. Subsidiary media does not include all potential links, just links which share a prefix with the current RSS document, which by default means all links subsidiary to the parent of the RSS document as specified in an atom:link

  More information on this soon when iffy:attachment is defined

The four values represent nested, hierarchical levels of commitment. Ping commits to nothing more than the spec requires. Media makes every commitment promised by the prior three levels, and an additional one.

If not specified, no commitment is made, the feed should be considered Ping.

Example:

<?xml version='1.0' encoding='UTF-8'?>

<rss version="2.0" xmlns:iffy="http://tech.interfluidity.com/xml/iffy/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/">
  <channel>
    <title>tech — interfluidity</title>
    <atom:link type="application/rss+xml" rel="self" href="https://tech.interfluidity.com/feed/index.rss"/>
    <iffy:completeness>Content</iffy:completeness>
    <!-- Other channel elements -->
    <item>
      <!-- Other item elements -->
    </item>
  </channel>
</rss>

Solely an item level element

IF AND ONLY IF an item contains an atom:updated element AND the guid of this item has been modified from the original, pre-update item in order to encourage feed consumers to surface the update, THEN the guid of the original post MUST be included in an iffy:original-guid element so that aware consumers can tie the update back to the original.

Example:

<?xml version='1.0' encoding='UTF-8'?>

<rss version="2.0" xmlns:iffy="http://tech.interfluidity.com/xml/iffy/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/">
  <channel>
    <title>tech — interfluidity</title>
    <iffy:when-updated>Resurface</iffy:when-updated>
    <!-- other channel-level elements -->
    <item>
      <title>Names too on the nose</title>
      <guid isPermalink="false">
        https://tech.interfluidity.com/2024/04/09/names-too-on-the-nose/index.html#updated-2024-04-14T05:55:00Z
      </guid>
      <link>https://tech.interfluidity.com/2024/04/09/names-too-on-the-nose/index.html</link>
      <iffy:original-guid>https://tech.interfluidity.com/2024/04/09/names-too-on-the-nose/index.html</iffy:original-guid>
      <atom:updated>2024-04-14T05:55:00Z</atom:updated>
      <!-- other item-level elements -->
    </item>
  </channel>
</rss>

When an item level element

If present in an item, the item contains a sequence of one or more atom:link elements, each of whose

• rel attribute is MUST BE via
• href attribute MUST BE the URL of an RSS feed from which the base contents of this item were drawn
• type attribute SHOULD BE application/rss+xml

If the item from which the current item was sourced does not contain an iffy:provenance, then the current item should include just one atom:link.

If the item from which the current item was sourced does contains an iffy:provenance, then the current feed SHOULD include all items of that element, with the URL of the feed from which the item was sourced PREPENDED.

This will ensure the most immediate source will be the first atom:link element. The origin — or at least the source for which no further provenance is known — will be the last atom:link element.

Processors may expect a channel level atom:link element with rel="self" and type="application/rss+xml" to use as the basis for provenance in source documents. See RSS Best Practices.

Example (from here):

<?xml version='1.0' encoding='UTF-8'?>

<rss version="2.0" xmlns:iffy="http://tech.interfluidity.com/xml/iffy/" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <channel>
    <title>interfluidity, all blogs</title>
    <!-- Other channel elements -->
    <atom:link type="application/rss+xml" rel="self" href="https://www.interfluidity.com/unify-rss/all-blogs.rss"/>
    <item>
      <title>Industrial policy and ecosystems</title>
      <guid isPermalink="true">https://drafts.interfluidity.com/2024/05/11/industrial-policy-and-ecosystems/index.html</guid>
      <author>nospam@dev.null (Steve Randy Waldman)</author>
      <link>https://drafts.interfluidity.com/2024/05/11/industrial-policy-and-ecosystems/index.html</link>
      <!-- Other item elements -->
      <iffy:provenance>
        <atom:link type="application/rss+xml" rel="via" href="https://drafts.interfluidity.com/feed/index.rss"/>
      </iffy:provenance>
    </item>
  </channel>
</rss>

May be both a channel and item level element. Item-level specification overrides channel-level specification.

Contains one of the following three values:

1. Ignore
2. Resurface
3. Reannounce

iffy:when-updated suggests how feed consumers should handle items containing atom:updated elements.

• Ignore suggests that feed consumers simply ignore the notification. Feed consumers should update any cache of the item contents (as they should do in the absence of an atom:updated tag.
• Resurface suggests that consumers that present multiple items in reverse-chronological order should present the new item, sorted at its update time rather than its initial publication date. Consumers that "announce" items one at a time (such a e-mail newsletter gateways, Mastodon / Twitter / SMS notifiers) should not re-notify the item.
• Reannounce, like Resurface, suggests that consumers that present multiple items in reverse-chronological order should present the new item, sorted at its update time rather than its initial publication date. However, Reannounce suggests consumers that "announce" items one at a time (such as e-mail newsletter gateways, Mastodon / Twitter / SMS) notifiers SHOULD re-notify the item.

Implementation Notes:

• Currently, very few feed consumers handle iffy:when-updated.
• To give effect to these values, it is recommended that, at levels Resurface and Reannounce, items be given updated guid values, so that existing consumers perceive them as distinct items.
• Naive announcement consumers, however, will then treat all atom:updated events as Reannounce, until they are explicitly modified to support this tag.
• Announcing consumers are much rarer and fewer than multiple-item-presenting consumers, so hopefully this will not be too great a burden. Ideally, eventually, feed consumers will widely support this tag and there will be no need for the "hack" of switching guid values.
• Implementations that modify guid values when updated MUST also provide the iffy:original-guid element!
  • See iffy:original-guid

Example:

<?xml version='1.0' encoding='UTF-8'?>

<rss version="2.0" xmlns:iffy="http://tech.interfluidity.com/xml/iffy/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/">
  <channel>
    <title>tech — interfluidity</title>
    <iffy:completeness>Content</iffy:completeness>
    <iffy:when-updated>Resurface</iffy:when-updated>
    <!-- other channel-level elements -->
    <item>
      <title>Ceci n'est pas un post</title>
      <guid isPermalink="true">https://tech.interfluidity.com/2024/04/09/ceci/index.html</guid>
      <link>https://tech.interfluidity.com/2024/04/09/ceci/index.html</link>
      <atom:updated>2024-04-14T05:55:00Z</atom:updated>
      <iffy:when-updated>Ignore</iffy:when-updated>
    </item>
  </channel>
</rss>