Netscape Dumps Critical File, Breaks RSS 0.9 Feeds

An anonymous reader writes "In the standard definition of RSS 0.91, there are a couple of lines referring to 'DOCTYPE' and referencing a 'dtd' spec hosted on Netscape's website. According to an article on DeviceForge.com quite a few RSS feeds around the web probably stopped working properly over the past few weeks because Netscape recently stopped hosting the critical rss-0.91.dtd file. Probably someone over at netscape.com simply thought he was cleaning up some insignificant cruft." Some explanation has been offered by a Netscape employee.

Did you think this through?

[Anonymous Coward]

Normal SGML and XML parsers just treat the DTD URL as an opaque string, not as something that can be retrieved.

Of course they retrieve it - unless they already have a local or cached copy. How else would they be able to parse a document marked up using a custom DTD?

Don't answer - go hang your head in shame.

Re:Why would this break RSS readers?

[acroyear]

Actually the DTD is loaded up by pretty much every proper XML library even if validation is "off".

The DTD contains more than just the element definitions and hierarchy. Its also used to define entities (&...;) that are non-standard to XML but may be expected in the file. HTML has tons of pre-defined entities but XML only has the core 4. All others are defined in DTDs and loaded on the fly as part of the processing.

There are ways to turn it off at the lowest levels, but higher-level abstractions/libraries might not give access to that. For example, with JAXP + SAX you can turn off DTD loading, but Jakarta Commons Digester doesn't give a setting where you can trigger that, so Digester tries to load the dtd, and even with validation off you can't change that. My only recourse is to take the DTD lines out of the various config files. (Reason: My JBoss server is deployed in private networks where the server can't reach the internet).

Did you read the XML specification?

[Anonymous Coward]

Non-validating processors are not required to read any external DTD subset.

Netscape Says No RSS 0.91 For You

[gastropod]

From April 2001, "Netscape removed the RSS 0.91 DTD from their website. This means that all RSS feeds which depend on the RSS 0.91 (many, MANY news sites) cannot be used with a validating parser." [slashdot.org]

It seems as though it just took them 5+ years to follow up on the threat? Primary links are broken, but of course the lively /. discussion (which, um, I haven't read) remains.

Sorry about that

[christopherfinke]

my.netscape.com is undergoing a redesign, and when we announced the redesign [netscape.com] about 10 days ago, the DNS entry for my.netscape.com was changed to point to the new server where My Netscape will be living. This had the effect of making anything under the old my.netscape.com unavailable, since the only thing public on the new server is a splash page. (Nobody on the team was especially aware of this DTD file since all of the old Netscape employees were let go last year around the time Netscape.com was redeveloped; anybody working at Netscape now was hired since then.)

Now, why this file was living under my.netscape.com is anybody's guess, but we'll have it restored ASAP. I only wish that someone had brought it to our attention so that I didn't have to find out about it from Slashdot.

Christopher Finke
Netscape Developer

Re:Sorry about that

[mmurphy000]

What's the official way to let you know about this sort of thing? I'm not trolling -- the better you can inform folk like us about how to interact with you, the more likely it is you'll get a response when you need it. For example, a quick scan of the Help and FAQ pages linked to off of the Netscape home page shows no mention of how to contact folk like you.

Re:Did you think this through?

[Thuktun]

Of course they retrieve it - unless they already have a local or cached copy. How else would they be able to parse a document marked up using a custom DTD?

A DTD is used when the parser wants to validate the document at parse time. It isn't needed for parsing. Having a DTD present won't necessarily allow your XML application to interpret random XML you didn't expect.

Re:Sorry about that

[christopherfinke]

What's the official way to let you know about this sort of thing?

You're correct that contact information appears to be MIA in the Netscape Help pages; I'll make sure to remedy that ASAP.

For something as serious as this, a user could have checked the profile of one of the Netscape Anchors or developers, where many of them list their screennames or websites, and subsequently, their e-mail addresses. (At least, I know I do [netscape.com].) Alternatively, any Netscape.com member could use Netscape sitemail to contact any of the staff members. Obviously, these are unacceptable for normal circumstances, but I wouldn't call this situation a normal circumstance.

Re:You gotta be kidding me...

[christopherfinke]

You make several good points that I want to respond to more fully, but I've got to run out, so I'll have to do that later. In the meantime, I'll put this out there: my e-mail address is [e-mail] [mailto]; my screenname and other contact information is available at my website [efinke.com]. Anyone who wishes to do so can contact me regarding issues with any of the Netscape websites or the Netscape browser; if I can't solve your problem, I can definitely get you connected with the right person.

Re:Why would this break RSS readers?

[Mithrandir]

What you need to implement is org.xml.sax.EntityResolver. There's several methods that need to be implemented that are the different ways the SAX parser could query for stuff. Basically it will give you the Public ID and/or System ID and ask you to return a stream to what that resolves to. Then, in your code, all you do is run a hashmap that maps a given ID to a local resource (eg file or database BLOB) and then do your own stream opening/processing from there. I attempted to post some example code but seems like that trips the lameness filter :( So, just have a look at the interface. The code required is pretty trivial to implement. If that fails, you should be able to work out my email address from the website address under my profile - send me an email and I'll send you the code we use in one of our projects.

Re:Then they're broken!

[Bogtha]

That's just wrong, you should try software authored by folk who know what they're doing.

It's called a non-validating processor and it's totally compliant with the XML 1.0 specification [w3.org].

Re:Then they're broken!

[Bogtha]

it's not as if you could handle any random DTD.

Yes, that's totally feasible. You're mistaking the semantics of document types with the external DTD subset.

It's true that inventing new element types and putting them in your DTD isn't going to magically make software understand what those element types mean. But DTDs provide other information - for instance, what entity references expand to, which attributes are IDs, and so on. This is useful information and can be processed in a generic fashion.

Re:Sorry about that

[christopherfinke]

URLs are forever!

Indeed, words to live by. I wouldn't pin this mistake on one person not checking the right logfile though; in a company as large as AOL, when an entire 150-person workforce is laid off and a new (much smaller) team is brought in to manage the old properties, things sometimes get lost in the shuffle. The entire my.netscape.com service happened to be one of those things. I'm sure that this incident will act as a reminder to never let this type of thing happen again.

And BTW, it appears that the DTD file will be restored early tomorrow morning at the latest.

Re:Sorry about that

[VGPowerlord]

They removed every file, causing a spike in 404s for all of them.

Re:You gotta be kidding me...

[Alphab.fr]

) The 2001 deletion of Netscape Developer. This lost a ton of Netscape copyrighted Javascript documentation. Unless I'm mistaken, this has been (quite some time afterwards) transfered to the mozilla fundation, and can be accessed at http://developer.mozilla.org/en/docs/JavaScript [mozilla.org] Cheers,