The document provides an overview of web services, explaining their definition, functionality, and different types including SOAP and REST architectures. It details the advantages and disadvantages of web services, highlighting their interoperability and ease of implementation, while also noting security concerns and performance issues. Additionally, it provides examples of web services in various sectors such as social networking and e-commerce.

1. Distributed Information System
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2. Summary
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1 – What are Web services ?
2 – How does a Web service work?
3 – Different types of Web services.
4 – Examples
5 – Conclusion

3. 1 – What are Web services ?
2 – How does a Web service work?
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- Application Programming Interfaces (API)
- Request services
- REST architecture
- SOA architecture
- OASIS
- World Wide Web Consortium (W3C)

4. 1 – What are Web services ?
2 – How does a Web service work?
3 – Different types of Web services
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- The client sends a request
- Request encoded in XML
- Function (GET, POST…) in the file
- The server decodes the file
- The function is executed
- A new XML file is encoded
and re-send to the client
=> Clients and servers communicate over the HyperText Transfer Protocol (HTTP).

5. 2 – How does a Web service work?
3 – Different types of Web services
4 – Examples
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- SOA defines WS-* Web Services
- Communication protocol: SOAP
- Web Service Description Language (WSDL)
for description
- UDDI (Universal Description Discovery and Integration)
directory
=> Service-oriented architecture (SOA):

6. 2 – How does a Web service work?
3 – Different types of Web services
4 – Examples
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Advantages :
- Interoperability between applications on many platforms
- Use open protocols
- Data and protocols are in plain text
- Thanks to HTTP protocol, Web services can run through firewalls
- Easy to implement
=> Service-oriented architecture (SOA):

7. 2 – How does a Web service work?
3 – Different types of Web services
4 – Examples
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Disadvantages :
- Norms are sometimes recent
- Low performances
- HTTP protocol: Web services can circle security measures
implemented by firewalls
=> Service-oriented architecture (SOA):

8. 2 – How does a Web service work?
3 – Different types of Web services
4 – Examples
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=> Representational state transfer (REST):

9. 2 – How does a Web service work?
3 – Different types of Web services
4 – Examples
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Advantages :
- Easy to maintain
- No state client administration: Less memory used, simplicity,
simultaneous requests, several servers …
- Using URI: setting up cache servers
=> Representational state transfer (REST):

10. 2 – How does a Web service work?
3 – Different types of Web services
4 – Examples
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Disadvantages :
- The client has to keep locally all necessary data for a request:
High consuming network bandwidth
=> Representational state transfer (REST):

11. 3 – Different types of Web services
4 – Examples
5 – Conclusion
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Social Networking (Facebook, Twitter…)
Travel agency (Ryanair, EasyJet…)
Video sharing (Youtube …)
Blogging (MySpace, Blogger…)
E-Commerce (Amazon, Ebay…)
Maps (Google maps, Mappy…)

12. 4 – Examples
5 – Conclusion
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- Growing since 2000
- Security problems (HTTP)
- REST architecture more and more common
. . . QUESTIONS ? . . .