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Why are RSS and XML used?

06:38 / 19.08.04

Same as title, i've read a few things on RSS but i don't get it, same with XML, why are they used and are they really that essential or do humans just enjoy creating more and more computer languages? I could understand XML if i read a little more about it i suppose (web-designers, site admin/owners markup language for easier navigation is all i have at the moment), it's RSS that i'm wondering about the most.

There's so many things out there now (computer languges etc) that you could really fry your brain trying to learn it all. Actually i don't think you could unless your planning on having a really, really long life.

15:00 / 19.08.04

D00d,

Perhaps you are thinking of XML as a kind of fancy HTML. Understandable but wrong. XML is a way of wrapping up data. It used more to transport data than anything else. For instance, I'm working with an application right now that using XML to communicate with other applications. That means that as long as the two applications know how to read XML and have agreed on what tags they can both understand from that XML they can communicate...no need to write custom protocols...so XML is like a universal way of wrapping up data that you know everyone will be able to understand.

RSS isn't that for syndicating websites?

15:15 / 19.08.04

RSS is a particular format for XML to come in. As Buk says, it is for syndicating websites (Really Simple Syndication). It is XML, they are not separate.

XML is not much of a language on its own, it's more like a set of rules to use to create other languages.

16:10 / 19.08.04

I've been using XML in conjunction with FlashMX. XML is (as far as I can tell, I'm not really up on the "theory" of it, and statements alluding to using it to "make a language" make my brain hurt and my ego weep) a widely-supported way to package data strings and give them custom names. That's the utility I've found in it. Essentially, it looks like HTML (scripted in a text editor, uses opening and closing tags), but it lets you use any damn names you want. I tend to think of XML files more as a database that another language (such as HTML, or actionscript) can draw from or write to.

What are you using it for?

17:54 / 19.08.04

Yay! Geek patrol! I wondered why Fridgemagnet hadn't replied to this sooner.

Someone explain Com+ proxy stubs to me!

20:05 / 19.08.04

Eion: also, RSS isn't just a language for humans to read. It's a language also for machines to read; it's fairly simple to write and very simple to automate, especially when hooked up to any kind of content management system - not just a weblog, but a news site, for instance; the BBC and the Telegraph have great XML/RSS feeds.

And when you've got stuff in an easily understandable, standard format, it's really easy for it to be automatically syndicated elsewhere. A script checks a BBC RSS feed. It notices it's updated. It publishes the most recent five links from it on a site I run, and when someone clicks, they go to the BBC. That's an example, but it aids automated syndication and market base.

RSS is a neat way of syndicated readily-updatable content. The easiest language to do this in is XML, which is, as everyone said, like HTML but with user-defined namespaces by default. You can also hook it up to predefined namespaces, for instance, in an RSS feed. XML describes data by categorising/tagging bits of it. Which is exactly what you need in an RSS feed.

Maybe you could explain a bit more what you don't get, but it fulfils a particular task particularly neatly, and in a way that (X)HTML simply cannot?

04:15 / 20.08.04

Sorry i forgot all about this. I'm not actually planning on using XML or RSS, but after looking at other things i can work out how they'd work, but with you being able to put in any name for an XML tag i just found it confusing how a computer would be able to do anything with it.

Like in HTML each tag has a function that the computer reads and then displays something on the screen, but with XML i just saw it as wierd that it doesn't do that and wondered how it worked. With RSS i clicked on the feed at a site and just didn't have a clue why it was there. I looked like a HTML page with all the tags in, but not doing anything. It's probably the 'ML' in XML that's confused me and i thought that it was just a new version of HTML, but i've read that it's not really anything like it.

Thanks for the help anyway, i just thought it would annoy me if i keep seeing XML and RSS being talked about and used and not understanding how it could possibly work.

09:49 / 20.08.04

Yeah, it's the "ML" thing that's confusing you.

HTML has a sole purpose: to be interpreted by a browser.

XML is used by a huge variety of applications. The latest Microsoft Office file format is basically a custom-form of XML. So is an RSS feed. So are many other file formats.

XML is a set of rules for producing files; it's not a set of rules for making files for one application. So I couldn't read an Office file in my RSS reader, even though they're both using XML - they use entirely different tags.

The joy of XML is that it can describe any data that can be categorised - FOAF, RSS, contact information, magazine contents - can be represented in it. The XML file doesn't need to explain how the tags within it are to be used - the software at the other end does.

Of course, the other thing you can do is make an XML file display correctly in a browser; I believe this uses XSLT but I'm not very up on that... from what I know, I think it allows XML tags to be mapped to HTML tags.

And, of course, then there's XHTML, which is the beginnings of the cross from HTML to XHTML. You know how at the beginning of an HTML file, there's a namespace defined? That points to a DTD file on the web that defines what all the XHTML tags mean. Namespaces allow you to explain how an XML file should be understood.

So basically, XML is much like HTML, in that it's a markup language - for marking up content by describing it in tags. The difference is it's not necessarily presentational, visual, or even for people to read.

(Anyone who wants correct me, feel free)

nedrichards is confused

14:20 / 20.08.04

I would further add that XML is in no way presentational, apart from in those cases where structure controls presentation. That's what we have CSS and XSLT for.

sidenote: that's also why all those people talking about XHTML (like myself) care so much about seperating 'style from content'; because XHTML is HTML expressed as XML.