Saturday, July 10, 2010

UFO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ha ha ha ha ha ha

chinese-ufo.jpg

Apparently air traffic control at Xiaoshan Airport in China spotted a UFO on radar and was forced to divert flights until E.T. phoned the f*** home.

Arcing over Zhejiang's provincial capital Hangzhou, the UFO appeared to glow with an eerie white light and left a bright trail in its wake.


Stunned witnesses reported seeing a comet-like fireball in the sky and a number of local residents took photos of the strange ball of light.

'The thing suddenly ran westwards fast, like it was escaping from something,' he said.

Running from something is right. It's called US. "This planet is a shithole, lets GTFO and hit that titty bar." "The Milky Way?" "You know it, brotha -- high-tentacle!"

Chinese airport closed after fiery UFO is spotted flying over city [dailymail]

Thanks to Romeo, Jordan and Peter Pan > Jiff, who would have PEWed that sucker out of sky, full-nelsoned those alien scumbags, and beat the secrets of the universe out of their bug-eyed brains

YOU-TUBE ORIGINAL

What's bigger than 1080p? 4K video comes to YouTube

Today at the VidCon 2010 conference, we announced support for videos shot in 4K, meaning that now we support original video resolution from 360p all the way up to 4K. To give some perspective on the size of 4K, the ideal screen size for a 4K video is 25 feet; IMAX movies are projected through two 2k resolution projectors.

We always want videos on YouTube to be available in the highest quality possible, as creators intend. In December of last year, we announced support for 1080p, or full HD. At 4096 x 2304 pixels, 4K is over four times the size of 1080p. To view any video in a source resolution greater than 1080p, select "Original" in the video quality pulldown menu:


To illustrate the power of 4K, please check out the videos in this playlist; each one was created by a filmmaker with access to a 4K camera. (Be warned: watching videos in 4K, even on YouTube, will require ultra-fast high-speed broadband connections).

Because 4K represents the highest quality of video available, there are a few limitations that you should be aware of. First off, video cameras that shoot in 4K aren’t cheap, and projectors that show videos in 4K are typically the size of a small refrigerator. And, as we mentioned, watching these videos on YouTube will require super-fast broadband.

We're excited about this latest step in the evolution of online video. We've been impressed by the 1080p videos you've uploaded over the last seven months and can't wait to see (in 4K!) what you do next.

Ramesh Sarukkai, YouTube Engineer, recently watched "New Dad State of Mind."

UPDATE (7/10/2010): Thanks to those of you who pointed out a few errors in the technical specifications in this post. We've corrected them and look forward to more of your feedback!

-from http://youtube-global.blogspot.com

Tuesday, June 08, 2010

APPLE IPHONE

Apple iPhone 4 is the next iPhone from Apple’s Cradle and we have listed down the full specification for the same and some interesting pictures also.It was expected only end of this year and they have come out with the release in june itself and will be available for sale on june 24th and its ready for pre order by june 15th. We will see the specifications now.
iPhone 4 Specifications
>Retina Display with 326 pixels per inchpixels per inch and has 78% of the pixels on an iPadiPad
>960×640 pixels display
>3.5 inch
>9.3mm thickness
>Apple A4Apple A4 Chip
>upto 32GB internal memory
>microSIMmicroSIM Card
>Bigger Battery
>5 Megapixel Camera with LED Flash and 5x zoom and tap to focus
>HD video Recording
>Video Calling Camera
>WiFi (n)
>Video Editing with iMovie
>Bluetooth
>Quadband GSM / 3G / HSDPA/ HSUPAHSUPA
>7.2 Mbps download speeddownload speed , 5.8 Mbps upload
>Dual mic for noise suppressionnoise suppression
>GPS, Accelerometer, Compass
>Gyroscope
>Battery Life : 7 hours 3G talktime , 6 hours browsing, 10 hours WiFi, 40 hours of music, and 300 hours of standby
>runs on iOS4
>Uses glass for Scratch resistance
They are Planning to sell this phone first in 5 countries which for sure doesn’t include India, but think it will be available in India by September or so which will be the time that all the telecom company will be ready with the 3G gun and everyone will like to sell iPhone at that time .But for sure it will be costly in India like any other iPhone.It will go on sale for 199$ in US for 16 GB and 299$ for 32 GB phone.

Saturday, February 20, 2010

XSS IN GOOGLE BUZZ

You may or may not have noticed, but I was on hiatus for a few days. As you’re probably aware (and I’m sure many of you celebrate) it was Chinese New Year on February 14th so I was offline for a few days taking a well deserved break.

I’d like to wish all of you that celebrate it a Happy Chinese New Year.

Anyway the big news during this period, especially in the whole social networking scene has been Google Buzz. Is the next challenger to Twitter or Friendfeed or even Facebook? Personally I think not, but it sure has got people talking.

Google has fixed a cross-site scripting bug that allowed attackers to take control of Google Buzz accounts. The bug affects the mobile version of Buzz and was reported Feb. 16 by SecTheory CEO Robert Hansen. Google patched the vulnerability the same day. According to Hansen, news of the flaw was passed along to him by a hacker with the moniker of TrainReq.

“There [are] four things of note here,” Hansen blogged. “Firstly, it’s on Google’s domain, not some other domain like Google Gadgets or something. So, yes, it’s bad for phishing and for cookies. Secondly, it’s over SSL/TLS [Secure Sockets Layer/Transport Layer Security] (so no one should be able to see what’s going on, right?). Third, it could be used to hijack Google Buzz—as if anyone is using that product (or at least you shouldn’t be). And lastly, isn’t it ironic that Google is asking to know where I am on the very same page that’s being compromised?”

The news from the last few days included a cross site scripting flaw in the mobile version of Google Buzz.

It was fixed promptly because the guy that discovered it was kind enough to tell Google about it.

As always though if something was discovered so quickly and reported so quickly how many more flaws are there being used by the bad guys out there.

Hansen was referring to the location feature in Buzz that shows where Buzz users are when they post. This feature can be turned off by the user.

“We have no indication that the vulnerability was actively abused,” a Google spokesperson said. “We understand the importance of our users’ security, and we are committed to further improving the security of Google Buzz.”

In the week since Buzz was launched Feb. 9, Google has faced criticism over privacy issues associated with the service. On Feb. 16, the Electronic Privacy Information Center filed a complaint with the Federal Trade Commission that charged Google with failing to protect users’ privacy. In an interview with eWEEK, Google Vice President of Product Management Bradley Horowitz said the company did not expect the negative response that Google Buzz received on the privacy issue.

There was also a big outcry about privacy when Buzz was launched due the fact it automatically populates your following list with people you often converse with.

Imagine if you’d been hunting for a new job and talking to someone from a competitor and your boss saw it? Or a husband chatting with another woman and his wife saw who he was ‘following’? There are a lot of permutations, all of which are not good so use your imagination.

eWeek also did another article about the privacy concerns here – Buzz Privacy Backlash.

Source: eWeek

Friday, February 19, 2010

lucky or Unlucky??????????/

Cell phone Myths

The internet is rife with rumors about the miracles of cellular technology, as well as the dangers.  Depending on who you believe you may be carrying around a miracle tool or a death trap in your pants and Lord knows that’s a lot of stress for one person to deal with.  Best to get to the bottom of things and separate truth from fiction.

1. Your cell phone can unlock your car
No one seems to know where this story came from, but it’s been circulated in a number of emails.  The basic idea is that you’re out and about and in your frenzy to get things done, you lock your keys in the car.  Crap.  But, being clever and knowing you have a spare set complete with keyless entry at home, you call home and have someone press the button on your spare set to unlock your car over the phone.  The signal goes through the phone, to your car and you’re driving again.  Now that’s crafty.
http://www.youtube.com/watch?v=0bjQMzI9m5w
So popular is this myth that the Mythbusters themselves had to test it.  Guess what they discovered… you’re going to be pointing your phone at your car for a long, long time.
The problem is the phone uses an audio frequency while your keyless entry is on a much higher radio frequency.  Which is to say you’re dealing with apples and oranges and once that keyless frequency hits your cell phone, it’s not going to get translated through to the other side at the same frequency.  So no, you can’t unlock your car with your cell phone, unless you plan on using it to break a window.

2. Cell phones cause gas pump explosions
This winner has become so ingrained in our minds that gas stations actually have signs asking you to not use your phone while at the pumps for fear of a massive fireball of death and destruction, all because you needed to say goodnight to grandma.  But when’s the last time you saw this happen on the news?
As it turns out, in the entire history of the entire world, there has never been an incident where someone blew themselves or any gas stations up with a cell phone.  It’s a complete fabrication.
According to Snopes, the story just showed up one day in 1999.  And every time it got mentioned, they said the explosion happened somewhere else.  So basically it’s a friend of a friend story, only in this case the friend is an explosion, and no one’s ever seen it in person.
The Cellular Telecommunications Industry Association and the American Petroleum Institute both agree that phones just don’t blow things up and they’ve never seen any evidence to suggest they do.  Any news reports that have attributed fires to the use of phones were later proved false when someone, you know, actually looked for the real cause.

3. Cell phones cause deaths in hospitals
Similar to no phones at the gas pumps, most hospitals have signs in place telling you to turn off your phone.  While some have phone use in designated areas which us regular folks assume must be lead shielded rooms or some such, other hospitals ban them altogether.  The fear is that cell phone signals may interfere with the machines being used to keep people alive.  There are even reports that the use of cell phones in hospitals has been a contributing factor in the death or serious injury to patients as a result of machines malfunctioning, delivering incorrect amounts of medication and so on.
However, the FDA has no information whatsoever on cell phones causing any deaths in hospitals the FDA has no information whatsoever on cell phones causing any deaths in hospitals, nor has any medical journal mentioned it.  Reports that cell phone interference has caused incubators, heart monitors and IV pumps to go all wonky are the main cause behind the cell phone bans in hospitals, however the evidence for these is also sketchy.  Just what is it that would cause the problem, anyway?
In 2007, the Mayo Clinic decided to do a study to see what the effect of cell phone interference was, so they used phones near 200 different pieces of hospital equipment.  The end result was that the observed no clinically important interference at all.
So are you safe using a phone in a hospital?  Probably, just keep in mind that if they have signs up and you refuse to put the phone away, they can and will have security take you out.  In 1998, a man in Massachusetts was pepper sprayed for not hanging up.  Probably best just to leave a message and call back later.

4. Cell phones cause cancer
This is the biggest one you’re going to find online with the most confusing answers.  There are literally hundreds, if not thousands, of websites that will assure you that cell phone use leads to brain tumors.
Dr Vini Khurana, a reputable neurosurgeon who trained at the Mayo Clinic, even wrote a paper back in 2008 that said cell phone usage caused more cancer than smoking or asbestos.  If you just said “holy crap” you’re well within you’re rights, as that’s a pretty damning statement.  But there is a but.
According to the World Heath Organization, and more than 30 other scientific reviews, cell phones do not pose a cancer risk.  And, apparently, Dr. Khurana’s work had not even been peer reviewed when it was released.
In a nutshell, cancer is caused by DNA mutations.  Some kind of radiation or chemical has to break down chemical bonds in our cells that lead to mutation.  But the radiation from a cell phone, the electromagnetic kind which is released by all kinds of electronics, is not strong enough to strip away electrons or break down chemical bonds, at least according to most scientists.  So cell phones just physically can’t cause cancer.   But why do people think they do?
Nearly every study on the link between cancer and cell phone use takes the time to point out that will no link is found, the risk of long term use requires further study.  Meaning that we found nothing, but if we kept going for a few years, maybe we would.  And leaving the door open like that has let people who are primed and ready to panic over their ear growing a second head walk right in.

5. Your cell phone can set you on Fire
Probably one of the last things you want your phone to do is spontaneously combust, especially if it’s in your pocket or, you know, against your head.  For the most part we like to think there are hard working men and woman out there ensuring that the products we use from day to day just don’t do that.  And while most things are pretty safe, very few things are 100%
Back in 2004, a teen in California was walking with her phone in her back pocket when, as witnesses say, it made a woosh sound, bulged a little, then spewed forth fist-sized flames.  The girl suffered 2nd degree burns.
So how could such a nutty thing happen?  An overheated battery.  Kyocera issues a recall of 140,000 batteries and the Consumer Product Safety Commission has issued recalls as well for certain batteries that can short circuit, overheat and, yes, burst into flame.
There have been other reported incident of phones bursting into flames while charging as well and though it’s rare, it actually can happen, though it seems to have been the result of poor quality batteries more than your phone angry at the poor grammar used in texting as you might think

6. Your phone can spy on you
This one has been a favorite of conspiracy nuts for the last few years, the idea that the government can tap into your phone and use it to track your whereabouts, or ever turn on the microphone and listen in on your conversations, whether or not you’re using the phone at that moment.
In fact, it’s true that the FBI has used this technique, calling “roving bug” to eavesdrop on criminals, like in New York when it was used as a surveillance tool in an organized crime investigation.  Traditional wire tapping of land lines is a bit too old school and criminals are on to it, so the FBI had to adapt.  Since many phones will never fully power down unless the battery is totally removed, a cell phone is a perfect wireless transmitter for law enforcement to tap into, and it still falls under the purview of existing wiretapping laws.
In other cases, though judges are have batted the attempts down due to a lack of probably cause, law enforcement has attempted to get access to information about cell phone use – locations of cell towers that took calls from individuals, strength and angle of signal and timing of calls, which would allow them to approximate the location of an individual.  You’ve seen it in television and movies before and, for all intents and purposes, it’s fairly accurate.  With access to cell company records, you could be tracked in real time based on your cell phone usage, or even just having the phone on and in your possession.

7. Your cell phone can explode
If you’re the kind of person who figures a cell phone fire is no big deal, you may be more inclined to be slightly nervous of cell phone explosions.  After all, fire can be our friend and let us roast weenies and such.  Explosions just suck, by and large.
Back in 2007, word came out of Korea that a man who had his cell phone in his shirt pocket died when the phone blew up, sending shrapnel into his heart and lungs.  Last year in China, a man died shortly after changing his phone battery when the same thing happened.  It was the 9th recorded phone explosion in the country over a seven year period.
In one incident, a man working in an iron mill died when it was determined that the heat of the mill caused the liquid in the battery to overheat and blow up.  So it may be rare, but it can happen.  Let that be a lesson to you, never expose your phone to molten metal.

8. Cell phones cause infertility
Potentially the most horrible rumor of all, at least for some people, is the one that says cell phones lower your sperm count.  And apparently it’s true.
Research conducted at the Center for Reproductive Medicine at the Glickman Urological and Kidney Institute at the Cleveland Clinic in Ohio suggests that there’s a chance using a cell phone is bad news for your boys if you’re the hands free type who keeps the phone in your pocket. Long term exposure to all that electromagnetic radiation so close to the goods may lead to an increase in body temperature.  And that can effect sperm count as well as mobility and shape.
The jury’s not out, of course, and odds are you need to be doing a lot of talking with the phone in your pocket, but probably to be on the safe side you could keep the phone over a couple of inches or two.  You never know

Tuesday, February 16, 2010

INTRODUCTION TO WSDL

In the past few years, a number of standards proposals have emerged in the past few years to provide a key piece of the XML middleware story: networked service requests. These networked service requests are a way to request XML-related functionality from a remote machine over a network such as the Internet.)

This has led to a standards race including notable entries such as Allaire Corp's Web Distributed Data eXchange (WDDX) (see Resources), UserLand Inc's XML Remote Procedure Call (XML-RPC), Microsoft's Simple Object Access Protocol (SOAP) by David Winer, IBM, Microsoft, and others (see Resources). At the same time, some developers have even done quite well building applications over plain old HTTP. The biggest growth area for such XML-based networked services have been in content exchange and syndication.

Similarly, there have also been a number of proposals for defining the descriptions and structure of such content. Of these, the notable ones include Information Content Exchange (ICE) from Vignette Corp and its partners (see Resources), and the RDF (Resource Description Framework) Site Summary (RSS) from Netscape and its partners (see Resources). Many developers have also done very well using the common Internet standard of Multipurpose Internet Messaging Extensions (MIME).

There are many, many other XML protocol initiatives out there; enough so that the W3C's has a brand new XML Protocol Working Group just for addressing these issues (see Resources). It should be very interesting to watch the political sparks fly as the W3C tries to extract something coherent from this welter.

In this bewildering array of ways to communicate between Web applications, a clear need has emerged for a mechanism to describe XML-based network services regardless of communications protocol and request structure. With such a mechanism many advanced Web development tasks could gain an additional measure of automation. For example:

  • Portal toolkits could provide a plug-in system for content sections to make it easier for designers to pick from a wide range of on-line services without delving into a lot of technical details.
  • Industry groups and service brokers could publish comprehensive white pages and yellow pages of on-line XML services, allowing developers to make quick technological assessments and comparisons.
  • Service providers could quickly publish updates and versions of their request structures in a standard format to help automate adoption by developers.

IBM, Ariba, and Microsoft set out to craft just such a mechanism, and on September 25th emerged with the Web Services Description Language (WSDL) version 1.0 (see Resources). It is rather odd that this "1.0" spec was pretty much under wraps until then; thus the XML community was left with no chance at a public review before the release date. At any rate, WSDL is a format for describing networked XML services, filling a large portion of the need I described earlier.

Background

WSDL occupies a space with many of its precedents overlapping some of the specifications. Let's take a brief look at the menagerie to provide some background. WebMethods' Web Interface Definition Language (WIDL), one of the pioneering specifications for description of remote Web services, was an XML format that took familiar approach (which was accessing functionality on a remote machine as if it were on a local machine) to users of remote procedural technologies, such as RPC and CORBA. There was some fit between WIDL and the XML-RPC system by UserLand. The former has since faded away, as message-based XML technologies have proven more popular than their procedural equivalents. The latter seems to be giving way to SOAP, which has support for message-oriented as well as procedural approaches.

SOAP describes envelope and message formats, and has a basic request/response handshake protocol. Additionally, Microsoft developed the SOAP Contract Language (SCL) earlier this year to provide a system for on-line service descriptions for SOAP-based applications. This work in SCL, in addition to other protocols and related work from IBM and Ariba, has pretty much been phased into WSDL.

Just before WSDL emerged, a consortium of 36 companies, including IBM, Ariba, and Microsoft, launched the Universal Description, Discovery and Integration (UDDI) system (see Resources), an initiative to provide a standard directory of on-line business services with an elaborate API for querying the directories and service providers.

Microsoft kept itself busy in the area of Web services description before WSDL emerged. It had created another entrant, Discovery of Web Services (DISCO) (see Resources), which is in now in limbo, outside Microsoft's official .NET strategic plan. DISCO describes how to find ("discover") SCL descriptions of services for a particular requirements. Frankly, reading the DISCO spec, it is hard to make heads or tails of the value it was supposed to provide, but whatever it had of use has since been sprinkled into UDDI and WSDL.

Parallel to Microsoft's efforts on SCL, IBM was creating the Network Accessible Service Specification Language (NASSL) (see Resources). One can also see that IBM threw its ideas fully into WSDL, and certainly its NASSL editors. IBM also got into the services discovery act with their Advertisement and Discovery of Services (ADS). There doesn't appear to have ever been a formal specification of ADS, though the Web Services Toolkit from IBM's alphaWorks project has a reference implementation of it (see Resources).

If you are thoroughly confused by now, you're in good company. More than one wag has quipped that XML is a specification with no other use but to spawn scads of other specifications. The formation of the UDDI group is supposed to help in the area of service description. Out of the current spaghetti should emerge a simple order, creating an overall protocol for deployment of Web-based services. This will probably be in the form of separate but linked formats for service discovery, description, request/response protocol, request structure and data-typing, semantic discovery, and, of course, transport protocol. Figure 1offers a suggested diagram representing this order and placing the various specifications I've mentioned accordingly. Hopefully, it will help clear up the landscape. Within this picture, WSDL handles the specific purpose of a description mechanism for services.


Figure 1. Service roles and interactions
Fig 1. Service roles and interactions

Sample WSDL document

Let's look at how WSDL works with SOAP through the following example. Let us say we are the entrepreneurs behind the imaginary company snowboard-info.com, an intrepid snowboarding industry database providing a service that allows others to query endorsements from snowboard manufacturers. A client can send a request to retrieve this information from a server using a SOAP request like the one in Listing 1. In natural language, Listing 1 encapsulates the question "Which professional snowboarder endorses the K2 FatBob?"


Listing 1. A SOAP 1.1 Request
<span>
POST /EndorsementSearch HTTP/1.1
Host: <a class="linkclass" href="http://www.snowboard-info.com/" style="color: rgb(76, 110, 148);">www.snowboard-info.com</a>
Content-Type: text/xml; charset="utf-8"
Content-Length: 261
SOAPAction: "<a class="linkclass" href="http://www.snowboard-info.com/EndorsementSearch" style="color: rgb(76, 110, 148);">http://www.snowboard-info.com/EndorsementSearch</a>"
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="<a class="linkclass" href="http://schemas.xmlsoap.org/soap/envelope/" style="color: rgb(76, 110, 148);">http://schemas.xmlsoap.org/soap/envelope/</a>"
SOAP-ENV:encodingStyle="<a class="linkclass" href="http://schemas.xmlsoap.org/soap/encoding/" style="color: rgb(76, 110, 148);">http://schemas.xmlsoap.org/soap/encoding/</a>">
<SOAP-ENV:Body>
<m:GetEndorsingBoarder xmlns:m="<a class="linkclass" href="http://namespaces.snowboard-info.com/" style="color: rgb(76, 110, 148);">http://namespaces.snowboard-info.com</a>">
<manufacturer>K2</manufacturer>
<model>Fatbob</model>
</m:GetEndorsingBoarder>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
</span>

In response, the server can send the SOAP 1.1 response (sans HTTP header) message for the foregoing request as shown inListing 2. In natural language, it encapsulates the simple string response "Chris Englesmann".


Listing 2. A SOAP 1.1 Response
<span><br /><SOAP-ENV:Envelope<br />  xmlns:SOAP-ENV="<a class="linkclass" href="http://schemas.xmlsoap.org/soap/envelope/" style="color: rgb(76, 110, 148);">http://schemas.xmlsoap.org/soap/envelope/</a>"<br />  SOAP-ENV:encodingStyle="<a class="linkclass" href="http://schemas.xmlsoap.org/soap/encoding/" style="color: rgb(76, 110, 148);">http://schemas.xmlsoap.org/soap/encoding/</a>"><br />  <SOAP-ENV:Body><br />    <m:GetEndorsingBoarderResponse xmlns:m="<a class="linkclass" href="http://namespaces.snowboard-info.com/" style="color: rgb(76, 110, 148);">http://namespaces.snowboard-info.com</a>"><br />      <endorsingBoarder>Chris Englesmann</endorsingBoarder><br />    </m:GetEndorsingBoarderResponse><br />  </SOAP-ENV:Body><br /></SOAP-ENV:Envelope></span>

Now the overall structure of requests, the relevant data types, the schema of the XML elements used, and other such matter are left to the trading partners by the SOAP specification itself. WSDL provides a standard for service specification that unites the types of requests and the requirements needed to process them.

In order to get all the hot snowboarding portals and discussion sites hooked up to our system, we might want to define WSDL communications ports. We do so by releasing the WSDL description of our point of service as shown in Listing 3. A WSDL description for a Snowboarding endorsement query

First, a bit of reassurance. Listing 3 may seem long, but WSDL is actually quite simple. Our sample WSDL document not only uses nearly every facet of WSDL, it also has a hefty chunk of XML Schema and also takes advantage of the SOAP binding to WSDL. This last portion, though presented in the same service description, is technically an extension to the standard service description.

The whole thing is enclosed in the  element that describes a set of related services. The element allows the specification of low-level data-typing for the message or procedure contents. Different mechanisms are permitted through namespace extensibility, but XML schemas are likely to be the choice for most users, and is used in our example. This specifies a simple element content model that you can see matches the sample exchange in Listing 1 and Listing 2. WSDL provides a system for importing data-type specifications located as separate resources, and there could be several such resources in cases of complex messages in multiple usage domains.

The  element defines the data format of each individual transmission in the communication. In our case, one message represents the EndorsingBoarder request and the other the response. In our example, this is a simple statement that the body of the message is a particular element from the schema in the types section. The breaking of a transmission into message parts depends on the logical view of the data. For instance, if the transmission is a remote procedure call, the message might be divided into multiple parts, one of which is the procedure name and meta-data and the rest of which are the procedure parameters. There is naturally a relationship between the granularity of the data-typing and the break-down of the message into parts.

The element groups messages that form a single logical operation. For instance, in our case, we can have anEndorsingBoarder request which triggers an EndorsingBoarder response, or in case of error or exception, anEndorsingBoarderFault. This particular exchange is grouped together into a WSDL port type. As you can see, the relationship to messages is made by qualified name reference.

There are only four forms of operations with built-in support in WSDL: one-way, request-response, solicit-response, andnotification. The latter two are simply the "inverse" of the first two, the only difference being whether the end point in question is on the receiving or sending end of the initial message. Basically, WSDL supports unidirectional (one-way and notification) and bidirectional (request-response and solicit-response) port types. Faults are only supported in the bidirectional port types, unlike the CORBA model -- I'll leave the inevitable controversy between the two approaches right there for now.

The WSDL document so far has moved from the concrete and physical (data typing) to the abstract and logical (messages and port types), with some reference between the two. The  element is the bit that firmly provides the connection between logical and physical model. In this case, it takes the operation we have defined through the abstract port type and connects it to a concrete description of how it is transmitted through SOAP. Here is where we come to the SOAP extensions to WSDL I mentioned earlier. WSDL also provides bindings to bare-metal HTTP and MIME, and full extensibility to other protocols.

Our sample binding specifies the GetEndorsingBoarderPortType as having the SOAP "style" of Document. The style can beRPC or Document, the former indicating a more procedural bent to the communication and the latter a message-exchange direction. Of course, the dividing line between these is quite broad, and I can imagine much fruitless discussion over whether a given port type is one or the other. My bias in this debate is to use Document nearly everywhere.

Our binding also specifies the network transport as HTTP -- SOAP can be transmitted by other means, such as SMTP. The  elements get down to the grit, mapping the individual messages in the port type to definition of the SOAP transmissions that actuate them. Note that we specify a SoapAction, which is required for SOAP over HTTP. The given value must be used in the HTTP headers of the actual messages in order to signal the "intent" of the message. This will supposedly allow intelligent proxying and firewalling of SOAP traffic some day.

The final element, , defines a physical location for a communication end-point. It uses the port type and binding specified earlier, and basically gives the Web address or URI for a particular provider of the described service. Naturally, in our example, it is the address where we have set up our SOAP server to traffic in snowboard product endorsement queries.

However, what if once having launched the service, it turned out to be a hit with users, and traffic begins to overwhelm our server? We might decide to set up a mirror, perhaps in Europe. In this case, the service is exactly the same, but we provide a separate URI from which it can be obtained. In the WSDL scheme of things, all we'd have to do to make this happen is modify our WSDL document to add another  element such as in Listing 4.


Listing 4. An alternative element for handling multiple sites.
<span><br /><service name="EndorsementSearchEuropeanService"><br />   <documentation>snowboarding-info.com Endorsement Service European<br />      Mirror</documentation> <br />   <port name="GetEndorsingBoarderPort"<br />      binding="es:EndorsementSearchSoapBinding"><br />      <soap:address location="<a class="linkclass" href="http://www.snowboard-info.co.uk/EndorsementSearch" style="color: rgb(76, 110, 148);">http://www.snowboard-info.co.uk/EndorsementSearch</a>"/><br />   </port><br /></service></span>

Notice the different service name and address. Now any users who find this WSDL document through whatever means of service discovery will have two options for where to make the actual request.

A few general comments on our WSDL example. You can see that WSDL leans heavily on XML namespaces. The XML namespaces given in the <definition> element's targetNameSpace attribute is by default attached to all the names used for the other top-level WSDL elements. Developers can use qualified names to refer to these elements using prefixes from the particular namespace declarations in scope. Note that the default namespaces are not applied to un-prefixed names within WSDL attributes. This is consistent with other places where the XML namespaces mechanism has been borrowed for use in disambiguating names in the character data of XML specifications. XML namespaces are also used to connect WSDL elements (and elements from binding extensions) to the data-typing provided in the <types> element. In our example, we use the default namespace, http://schemas.xmlsoap.org/wsdl/ to indicate the official elements of WSDL. However, the spec explicitly leaves wide open the option of extending the core elements using elements in other namespaces.

Overall this example is quite simple. It describes communication consisting of short SOAP transmissions, with two input strings and one output in each operation. WSDL could just as easily define multiple port types consisting of a myriad of messages that use the full, extraordinary range of XML Schemas. Then again, at least in the short term, more simple communications between XML service providers and users is more likely to succeed.