can't get my RSS to validate - Help!!

[lawrence (archive)]

I'm running this page:

http://www.krubner.com/rss/page938.xml

through this validator:

http://rss.scripting.com/?url=http://www.krubner.com/rss/page938.xml

I can't get this page to validate. I'm getting two errors:

1. pubDate must be an RFC-822 date 9 9
2. Undefined rss element: item 12 7

The second one makes no sense to me. "item" is used in all the examples they give for .91 RSS, so why is the validator giving me grief?

 

[Rolf Magnus]

I'm running this page:

http://www.krubner.com/rss/page938.xml

through this validator:

http://rss.scripting.com/?url=http://www.krubner.com/rss 2Fpage938.xml

I can't get this page to validate. I'm getting two errors:

1. pubDate must be an RFC-822 date 9 9
2. Undefined rss element: item 12 7

The second one makes no sense to me. "item" is used in all the examples they give for .91 RSS, so why is the validator giving me grief?

I don't know rss, but your items are direct children of rss, and according to the dtd, the only valid child element for rss is channel and the only valid parent element for item is also channel.

 

[Andy Dingley]

I'm running this page:

http://www.krubner.com/rss/page938.xml

through this validator:

http://rss.scripting.com/?url=http://www.krubner.com/rss/page938.xml

I'd believe George Bush before I trusted the accuracy of a validator from scripting.com -- and for similar reasons; both are always "right" (i.e. not obvious enough to clearly catch them at it) but they'll cheerfully redefine black as white to push their own agendas.

I can't get this page to validate. I'm getting two errors:

1. pubDate must be an RFC-822 date 9 9

2. Undefined rss element: item 12 7

You need to have <item> as a child of <channel>. This 0.91 feed has it as a child of <rss> (which is where RSS 1.0 places it, so that might have caused some confusion)

I wouldn't suggest 0.91 either, as a format for new work. 1.0 is best (a hobby horse of mine), but go to 0.92 as a minimum.

 

[lawrence (archive)]

I'm running this page:

http://www.krubner.com/rss/page938.xml

through this validator:

http://rss.scripting.com/?url=http://www.krubner.com/rss/page938.xml

I can't get this page to validate. I'm getting two errors:

1. pubDate must be an RFC-822 date 9 9
2. Undefined rss element: item 12 7

The second one makes no sense to me. "item" is used in all the examples they give for .91 RSS, so why is the validator giving me grief?

Thanks very much. I rearranged things and got it to validate, using the validator from scripting.com.

However, it still fails validation at
http://feeds.archive.org/validator/

The problem is "bad characters". I'm not sure how to start to debug that. What is the first thing I should look for?

I wrote the 0.91 script (a PHP script) first because I assumed it would be easy. I figured once I worked out the troubles at 0.91, I could move up and do scripts for 1.0 and 2.0. The fact that I'm having trouble even at the 0.91 level makes me happy that I didn't jump straight to the 1.0 or 2.0 level.

 

[Johannes Koch]

However, it still fails validation at
http://feeds.archive.org/validator/

The problem is "bad characters". I'm not sure how to start to debug that. What is the first thing I should look for?

Did you change anything? I get "This is a valid RSS feed." with http://feeds.archive.org/validator/>.

 

[Andy Dingley]

However, it still fails validation at

http://feeds.archive.org/validator/

The version this morning seems OK. I suggest you keep an archive of these bad feeds under static URLs, so that we can more easily see the problems.

The problem is "bad characters". I'm not sure how to start to debug that. What is the first thing I should look for?

Most likely thing is the use of HTML entities (like &eacute; ) that aren't valid because RSS is an XML protocol and doesn't recognise these HTML-defined entities. A _very_ common error in RSS feeds.

I wrote the 0.91 script (a PHP script) first because I assumed it would be easy.

I have to ask why anyone needs to write RSS scripts these days ? (Although I spent yesterday doing it myself). There are very many already out there, and it's a rare situation that really needs something written from scratch.

I suggest that you learn a bit more detailed XML (entities for one thing, namespaces for another) and learn how to read a formal DTD. It's one thing to make a feed work once during testing, but quite another to make a reliable feed that handles all the data it will meet over its lifetime. Sadly RSS tools suffer badly from this - they run for a week, then crash when they meet their first accented European character. To get a reliable feed, you really do need to know how to _understand_ the specification, not just match up one example.

As to the versions, then I'd support 0.92 and 1.0 1.0 is best, 0.92 solves compatibility issues for some older or simpler aggregators. 2.0 is pointless.

You don't need to understand Dublin Core to use RSS 1.0, but you will do if you want to really use it. Worth the effort of studying it anyway (Learning Dublin Core is vastly more useful than learning RSS anyway)

Hang in there - RSS versions don't really vary that much between themselves.

 

[lawrence (archive)]

The version this morning seems OK. I suggest you keep an archive of these bad feeds under static URLs, so that we can more easily see the problems.

Most likely thing is the use of HTML entities (like &eacute; ) that aren't valid because RSS is an XML protocol and doesn't recognise these HTML-defined entities. A _very_ common error in RSS feeds.

I'm stumped when I think of all the possible user inputs that can mess up an RSS feed. Myself and a friend have been working on some weblog software for a year now - the weblog entries show up in the RSS feed. Lots and lots of problems come up - people might copy and paste something from Word in their weblog and then get a Windows character that is not in the defined char set for the RSS feed. How to protect against that. Or people can, as you say, add in some HTML entities, or sometimes the software does that automatically.

It's true that I could write filters for each possible problem as it comes up, but it seems like it would take a mountain of code and there would never be an end to it - after I figure out how to convert unexpected European accented characters, then I'd have all the Asian alphabets to work on.

I guess I'm asking if there is an easy, elegant way to convert a set of characters to some particular character set. I don't know of any myself. What strategies have other programmers used when tackling this problem?

 

[lawrence (archive)]

(Andy Dingley) wrote:
I have to ask why anyone needs to write RSS scripts these days ? (Although I spent yesterday doing it myself). There are very many already out there, and it's a rare situation that really needs something written from scratch.[/QUOTE]

I think that is a fair question. Part of the answer would be, I guess, we want to be able to assert that our weblog software is "complete" in some sense. Without RSS, it is not complete. The other aspect of it, call it an institutional mission, is that we want to donate all our code to the public domain. That means we often have to do things from scratch, because other we might use is copyrighted. There is a lot of good code under the GPL, but the GPL is too restrictive for our purposes.

I suggest that you learn a bit more detailed XML (entities for one thing, namespaces for another) and learn how to read a formal DTD. It's one thing to make a feed work once during testing, but quite another to make a reliable feed that handles all the data it will meet over its lifetime.

I really would love to learn more about XML and I've bought a bunch books from O'Reilly. Sadly, I'm stretched a little thin. Me and some friends have been working on a content management system and I've had to learn a lot about a lot of different stuff, and I haven't had the chance to become very good at anything. I'd like to know more about XML, XHTML, Apache, CSS 2.0, RSS, Linux, Windows XP, mime types, character encodings, SOAP, Java, web services, Flash, PostGreSql, Swing, MySql, encryption and a whole lot more. It's all just too much. My hope, at this point, is they'll come a point when the basic abilities of our CMS are stable enough that I can go over it again and go deeper into certain areas when my knowledge is better. That, or maybe our project can pick up some programmers who are more talented than I.

We're giving away our (still quite buggy) software here:

http://www.publicdomainsoftware.org/

 

[Andy Dingley]

I'm stumped when I think of all the possible user inputs that can mess up an RSS feed.

Can't be done. Never was possible - users are just too inventive.

Instead, look at it the other way. Find the set of all things that are _valid_ RSS and exclude anything else. This is a smaller set than the invalid stuff, and it's better documented. If you _only_ allow the valid sequences, then you have implicitly forbidden all the invalid stuff.

Definitely read this
http://diveintomark.org/archives/2004/02/04/incompatible-rss

It's true that I could write filters for each possible problem as it comes up,

No, you can't. You might possibly manage to do it for one day, but there will always be something new coming along tomorrow. Take it the other way.

 

[lawrence (archive)]

Can't be done. Never was possible - users are just too inventive.

Instead, look at it the other way. Find the set of all things that are _valid_ RSS and exclude anything else. This is a smaller set than the invalid stuff, and it's better documented. If you _only_ allow the valid sequences, then you have implicitly forbidden all the invalid stuff.

Definitely read this
http://diveintomark.org/archives/2004/02/04/incompatible-rss

Thanks for the link to the Mark Pilgrim article. Despite the obvious anti-Dave Winer bias in the article, I thought it was very good and very informative.

I like your suggested style for moving forward but don't understand how to do it. Should I take an input (when a user posts) and take every character and put it into an array and then test it against an array full of those character's that are allowed? That seems cumbersome, though it only happens when the user inputs stuff, so being cumbersome at that point isn't lethal. But is there a more graceful way to validate the input?