Patch to add the guid tag to the rss feed [#26223]

This patch add the guid (globally unique identifier) tag to the rss feed. This is in line with the RSS 2.0 Specification, se below. It's a very simpel, one line patch, to the format_rss_item function in common.inc.

I want this personally so my news reader (NetNewsWire) can distinguish between new and updates posts.

From http://blogs.law.harvard.edu/tech/rss

A frequently asked question about s is how do they compare to
s. Aren't they the same thing? Yes, in some content systems, and no in others. In some systems,
is a permalink to a weblog item. However, in other systems, each is a synopsis of a longer article,
points to the article, and is the permalink to the weblog entry. In all cases, it's recommended that you provide the guid, and if possible make it a permalink. This enables aggregators to not repeat items, even if there have been editing changes.

Comment	File	Size	Author
#1	common_rss_guid_02.patch	524 bytes	frjo
#1
	common_rss_guid.patch	537 bytes	frjo

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Comments

Comment #1

frjo CreditAttribution: frjo commented 19 July 2005 at 06:09

Version:	4.6.2	» x.y.z
Status:	Active	» Needs review

File	Size
common_rss_guid_02.patch	524 bytes

I made a patch for the cvs version of Drupal also. I believe this is a smal but very nice improvement of Drupals RSS support.

Comment #2

Dries CreditAttribution: Dries commented 19 July 2005 at 18:32

guid has to be permanent. I don't think we can guarantuee that at the moment. People can set URL aliases and stuff, and these changes would change the guid.

Comment #3

Steven CreditAttribution: Steven commented 25 July 2005 at 14:59

Possible remedy: generate GUIDs by hashing the base url with the node id (optionally the word "node" too if we use this technique elsewhere).

Comment #4

Dries CreditAttribution: Dries commented 25 July 2005 at 19:43

Not quite. The problem is that $link is not necessarily unique (subject to change) as it can be aliased. foo.com/node/1 (non-aliased URL) is as unique as its hashed variant, and should be fairly unique (unless your are playing $base_url tricks). I think the solution is to pass a guid to format_rss_item() using the $args parameter.

Comment #5

Steven CreditAttribution: Steven commented 25 July 2005 at 19:56

I only meant those things: base URL, node ID and the word "node". Regardless of where it comes from. Perhaps we need a generic GUID generating mechanism. I chose the base URL as a unique "permanent" site-specific seed with the understanding that if your base URL changes, your feed location changes too and aggregators need to refresh anyway.

Comment #6

Damien Tournoud CreditAttribution: Damien Tournoud commented 25 July 2005 at 21:32

An open question: in the RSS feed, should the urls be aliased ones or "base" (/node/#nid) ones?

I do think base ones are better, because they are permanent and reliable. RSS is meant for automated processes. URL aliases are meant for humans.

-- DamZ

Comment #7

frjo CreditAttribution: frjo commented 26 July 2005 at 05:22

Thanks for your intrest in this issue.

Could you do add a line like this to the node_feed function in node.module?

$extra = array_merge($extra, array(array('key' => 'guid', 'value' =>  $base_url .'/node/'. $node->nid)));

Just below the line where pubDate is added in the same manner.

This seems more complicated than adding a $guid argument to the format_rss_item function in common.inc but maybe it's a bad idé to go around changing functions that other modules can be using.

Comment #8

Damien Tournoud CreditAttribution: Damien Tournoud commented 26 July 2005 at 08:21

I like the idea of building the guid from the $link. But for this to be consistant and permanent, we should use the "normal" node link, not the aliased one. So we must give an answer to my primary question.

-- DamZ

Comment #9

frjo CreditAttribution: frjo commented 26 July 2005 at 09:55

I believe the link tag should stay as it is, i.e. a standard Drupal URL with path alias if one is set.

The guid tag on the other hand need to be different as Dries stated, it must be a permanent URL. A URL with the format "base_url/node/nid" should do the job.

The code sample from my last comment can handle this I hope.

Comment #10

kika CreditAttribution: kika commented 26 July 2005 at 10:26

Status:

Needs review

» Active

atom.module also needs a GUID so it is probably worth to introduce a genereric function

Comment #11

Gábor Hojtsy

he/him

Hungarian

Hungary

CreditAttribution: Gábor Hojtsy commented 8 August 2006 at 19:56

Status:

Active

» Fixed

Drupal 4.7 and up has this feature. Look at http://drupal.org/rss.xml to see. It has <guid isPermaLink="false">77562 at http://drupal.org</guid> type guids.