Mood:
celebratoryNow Playing: 'Nocturnal Nuglets' Expedition seeks to find source of ancient king's super power. Warren Beady / Bill Muckluck
Topic: Notable Opinions
Some acronyms:
Blogs / Tim Ewald
Thursday, April 26, 2007
I finally get REST. Wow.Yeah, I'm alive. And I remember the password to my blog. I've been away for a bit, working on something very cool involving the TV. If all goes well, you'll hear about it in a big way. Anyway, I'm still having a ball out here in reality. Building something real has a way of focusing your decisions about technology.
...REMAINING BODY OF ARTICLE AT URL
Comments: (excerpted)
- # re: I finally get REST. Wow.Dennis
Posted @ 4/26/2007 7:03 PM
So, I've got Fielding's thesis, before I get started on all that I have one newbie question...how does that state transfer physically work? Ie., what is the REST equivalent of hyperlinks in HTML?
- # re: I finally get REST. Wow.Mark Baker
Posted @ 4/26/2007 9:31 PM
Dennis - state transfer refers to the exchange of data between agents, where the data represents the state of a resource at some point in time. Regarding links, links in HTML are RESTful; for other data formats, they'd also have to use links. - # re: I finally get REST. Wow.Mark Baker
Posted @ 4/26/2007 9:32 PM
Brian - the lack of "standard endpoint descriptions" in RESTful systems is a feature, not a bug. All resources expose the same interface, therefore there's no value in describing the differences because there aren't any! - # re: I finally get REST. Wow.Bill de hOra
Posted @ 4/27/2007 7:40 AM
"Say I want to model a chess opponent in REST. How do you do that in rest by modeling states?"
Post the move (or the entire board state) to the chess board. Plus, that's what distance chess players do more or less.
- # re: I finally get REST. Wow.Andrew Wahbe
Posted @ 4/27/2007 10:59 AM
For what its worth, a conversation about this with a colleague yielded the following: if you think of the rules of chess to be the "protocol" then you can model the game states as documents identified by URIs. You GET a clean board with links for all possible moves (ya there's a lot but so what). You GET the appropriate link to make a move. The server applies both your move and the opponent's move and returns a new document with the board state and options. And so on.
The contrast with Joe's POST-based solution is very relevant to the article. With that solution the client has to know the rules of chess to construct a valid new board; with the link-based solution, it doesn't.
(correction from later comment:) Sorry it was Bill not Joe... wrong REST guru ;-) - # re: I finally get REST. Wow.Andrew Wahbe
Posted @ 4/27/2007 10:59 AM
For what its worth, a conversation about this with a colleague yielded the following: if you think of the rules of chess to be the "protocol" then you can model the game states as documents identified by URIs. You GET a clean board with links for all possible moves (ya there's a lot but so what). You GET the appropriate link to make a move. The server applies both your move and the opponent's move and returns a new document with the board state and options. And so on.
The contrast with Joe's POST-based solution is very relevant to the article. With that solution the client has to know the rules of chess to construct a valid new board; with the link-based solution, it doesn't. - # REST as State Machine - Duh!David Van Couvering 's Blog
Posted @ 4/27/2007 11:26 AM
Tim Ewald get's the "aha" moment and shares it with the REST of us.
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intervening article with example further detailing Mr. Ewald's assertions not shown here.
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Friday, April 27, 2007
Ittay commented on my REST post:
the thing is, when you write software, you use an RPC model. what bothers me about REST is that it is not only an API. it enforces you to change your programming model.
that is not to say i don't like it. i do, for its simplicity and self documentation (e.g., provide all moves as links), but there is a price you pay.
When you write software, you use a programming model that works. And sometimes you have to change models. We changed them for the Web: we moved to the notion of pages. It wasn't RPC, it wasn't even objects (at least from most developers perspectives originally). But it was simple and did what it was supposed to do. I've done RPC, CORBA, DCOM, Remoting, RMI, and Web services. All of those technologies have their place. But they all struggle in a loosely-coupled, massively distributed world. I'll happily change my programming model to solve that.
Saturday, April 28, 2007
I've gotten several comments saying that, at the end of the day, REST is just RPC. That's wrong, for at least 3 very (good) reasons:
A MUST read for anyone still struggling and afraid to drop the SOAP.
One reason this discussion is important is because a machine's 'state' determines whether the machine (at the one specific point in time and at the one particular selected entry in the record of all states experienced by the machine from start to present) is in a proper state or has gotten lost. Thus, 'state' is used to examine and determine whether a software/hardware operation is in synch with all its various members and methods against some measure (here be dragons) what reality as the computer designer says it should be.
Thus, 'determinism' decides whether a computer is an experimental toy or a robust framework. That is why determining, tracking and auditing system state is essential... especially in an application comprised of web elements as any networked applications must be able to recover nicely after a connection is interrupted. Thus, state on a multi-platform web-based computer is much more critical than on a single-platform operating system. Windows NT was Microsoft's first fully deterministic operating system as it was able to maintain state information across all threads.
Now. Take SiteFlash and Emily and you can build a deterministic finite state machine (aka computer) using web elements and virtualized proprietary elements.
That's what all the hoorah is about Vertical Computer Systems intellectual property.
Notice Brother Tim left off this nasty habit of blogging last year, Here was the last post he made until Thursday April 26, 2007:
Wednesday, June 14, 2006
Are Excel Services the way to bring developers and business people together?
I heard about Excel Services a while ago, but hadn't had any time to look at them even briefly until now. Basically, it's a server-side system that lets you access data and calculations in Excel spreadsheets via Web services. Think about how much business data and calculation is done with Excel. Now imagine being able to leverage the directly. Want to change the algorithm you use to compute some key financial data? Let the analyst modify the spreadsheet and copy the update to your server and you're done. Now *this* is the way to align technology and business. Of course, that assumes it all actually works well - I haven't done anything yet. But still, it has *tons* of potential. Very cool idea, definitely something to spend more time with.
- # re: Are Excel Services the way to bring developers and business people together?Mark Nottingham
Posted @ 9/2/2006 2:19 PM
Totally. I put together a system like this in '97 for a brokerage firm; worked like a charm. Most "enterprise" data is in Excel; why not take advantage of it?
The other side of this, of course, is turning Excel into a first-class format on the Web by giving people the means of identifying individual cells, rows and tables from URIs, and giving them a little more formalism, so spreadsheets can be reused as services themselves.
More here:
http://www.mnot.net/blog/2005/08/13/excel_microformats - # re: Are Excel Services the way to bring developers and business people together?John Doe
Posted @ 10/7/2006 12:39 PM
For those who have seen Excel spreadsheets at work; this is a nightmare to support!
Wonder if anyone has thought about what will happen when excel pops up a message box on the server!!! - # re: Are Excel Services the way to bring developers and business people together?Brian Yang
Posted @ 10/7/2006 12:42 PM
I agree! Wonder why anyone would think that deploying excel to a server would be a good idea! - # re: Are Excel Services the way to bring developers and business people together?MikeD
Posted @ 4/26/2007 10:48 PM
Take a look at SmartSheet.com they use a spreadsheet metaphor (and look/feel) for server-based collaborative data and project management.
http://www.smartsheet.com/home
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Coincidentally, THIS happened June 14, 2006 (the date of Tim Ewald's last blog entry before he left for his REST hiatus):
- Wednesday, June 14, 2006
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The W3C XML Query and XSL Working Groups have updated the Candidate Recommendations for XQuery, XSLT 2 and XPath 2. The major change in these drafts is that several data types have migrated from the xdt, http://www.w3.org/2005/xpath-datatypes namespace to the W3C XML Schema xs, http://www.w3.org/2001/XMLSchema namespace. There are numerous small bug fixes and clarifications as well. Updated drafts include:
- XSL Transformations (XSLT) Version 2.0
- XQuery 1.0: An XML Query Language
- XML Path Language (XPath) 2.0
- XQuery 1.0 and XPath 2.0 Functions and Operators
- XQuery 1.0 and XPath 2.0 Data Model (XDM)
- XSLT 2.0 and XQuery 1.0 Serialization
- XML Syntax for XQuery 1.0 (XQueryX)
- XQuery 1.0 and XPath 2.0 Formal Semantics
........
Here's an interesting historical background (updated link 13Feb2010 - I find it troubling the archives for 2002 thru 2007 are missing) on Google and Amazon to name a few and their XML approaches back in April 2002. All the while VCSY was under seige by Ross Systems/Arglen. They seemed hella confident. All of them.
