From time to time, I will go to the 9CBS community to see, it is more than once, and many problems there are not clear because the basic concepts of Web Services are not clear. Seeing others, I will use it, I will take myself into the dead.
Here are some individual views, welcome to discuss.
Typical several:
1. How do Web Services actively feed back the information back to the client? (There is more than once someone asked)
Ask this question Most of the concept of Services. Web Services is Service's Provider. Since it is a Provider, it is a customer to request a service to the Web Services, and it is not possible. Some people will say "push" technology, in fact, the customer is also requested to Services, but it turns into an automatic polling. Think about it, the server does not know if the client does not open it. How to push? When the customer is turned on, ask the service provider "What is new in 12 o'clock yesterday?" Provider will "push" to the client.
Thought from data flow, there is always a sponsor and recipient in the data flow. If the initiator is a web service, who is the recipient? Someone thinks that it is the application that uses the web service, can I be turned off by the user? Or because what is the reason IP address changed (dial-up, DSL, DHCP environment is possible)? In this case, the feedback information of Services has no recipient. Even the basic connections can not be built, and don't say that the information is delivered.
There is also a more basic concept, which is a web connection, which is independent of each Web connection. HTTP connection Every request is not related to the front and reth, which is the advantage, of course, in some cases. Understand this, I know that Web Services will not send feedback to the client. Because it doesn't know who the client just is, even if he has not changed anything.
2. How to add an interface to Web Services?
Since it is a service, there is no interface, this should be the usual manner at the time of the foreigner, it provides services, not an interface with an interface. Imagine that foreigners thought of this idea, just wanted to separate FunctionAlity and Interface, so there was a SERVICE, and through XML and HTTP, this Services is more wide. Now I want to take it with it? This view is to completely violate the original intention of Web Services.
Let me talk, or a sentence, the concept is unclear. Nowadays, many technologies are very low, but this is under our conceptual premise. Otherwise, it is very big to walk into the dead alley.
