Microsoft Visual Basic .NET Tutorials
Web Services / What are Web Services?
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Subtitles of the Movie (Microsoft Visual Basic .NET / Web Services / What are Web Services?)
Web services are taking the world by storm, there are lot of these things flying around. I'll just go ahead and tell you that if you go to the UPS site and track a package, if you go to sites the different travels sites out there, these people don't have this huge server with all this data, they are using web services to connect to someone whose business already have the database out there. And they have exposed it via web services. Let's talk about exactly what they are; you can access components over the Internet it is exactly what it sounds like. We used to consume these services across a LAN using something like DCOM. But over the Internet this is a problem because the DCOM wants to hold a bunch of ports open, and of course the security folks won't let us get away with that. So this is a way we access components over the Internet. Now web services utilized HTTP, you'll recognize that: the hyper-text transport protocol. This is how the browser speaks to the web server, it utilizes XML to stream that data in XML format. And you can also use SMTP, and for the most part it does this over TCP port 80. TCP port 80 is the standard port for HTTP in most Internet connectivity. Thus most firewalls are already open on port 80. And so we can stream our XML data and our web services through that port. Now let's look at a web service. Normally if I have two machines on a network and I need to access data on another machine, I simply make a call across the network to the machine. And I'll use the technology like DCOM to get that data and that's not a big deal. However it gets little more challenging for me to access data that's in a more remote location and the Internet is sitting between me and them. What I am going to have to do now is basically go through the Internet into this other machine. Now that's not a big issue you accept that, this Internet area kind of represents the worst of mankind in lot of ways when it comes to security. There are all kinds of people out there who'll invade your machines. So we don't want to go across the Internet and open lot of ports, and this is same thing as opening lots of doors and windows in our house. It just provides another way for somebody to get in, and so with web services we are going to use port 80 which is open and secured and stream this data around. Now in the next video we are going to talk exactly about how they work, and then we'll get on to creating some of these and taking a look at them.
Tutorial Information
| Course: | Microsoft Visual Basic .NET |
| Author: | Mark Long |
| SKU: | 33433 |
| ISBN: | 1932072349 |
| Release Date: | 2003-05-27 |
| Duration: | 6 hrs / 87 lessons |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
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