1. Introduction to Web Services in the Microsoft .Net Framework

2. Contents Introduction to Web Services
Introduction to Web Services in the Microsoft .Net Framework
A Web Services Example: Microsoft’s .NET My Services
Creating a Web Service in Visual Studio .Net
Consuming a Web Service in Visual Studio .Net

3. Introduction to Web Services

4. Defining Web Services
A web service is a chunk of functionality that can be accessed using web technology
Across an intranet or the Internet
Usually:
What’s accessed is a method in a language such as Java or Visual Basic.NET
The web technology used is the Simple Object Access Protocol (SOAP) carried over HTTP
Both the .NET and Java camps have endorsed web services

5. Key Web Services Technologies
Web Services Description Language (WSDL)
An IDL for web services
Simple Object Access Protocol (SOAP)
An XML-based protocol for web services
Universal Description, Discovery, and Integration (UDDI)
A directory service for web services

6. Illustrating Web Services Technologies
SOAP
UDDI Registry
Internet
UDDI Registry
Application
Application
Application
WSDL Interface

7. Applying Web Services (1)
Connecting clients to Internet applications
One example is Microsoft’s .NET My Services
B2B integration on the Internet
The next generation of EDI
Enterprise application integration (EAI) on intranets
A standard approach to connecting all applications

8. Applying Web Services (2)
Reservations Application
Internet
Airline Reservation System
Intranet
Seat Availability Application
Pricing Application

9. Describing Web Services: WSDL
Created by Microsoft and IBM
Recently handed to the World Wide Web Consortium (W3C)
Endorsed by everybody:
Microsoft, IBM, Sun, Oracle, BEA, more

10. Accessing Web Services: SOAP
The Simple Object Access Protocol (SOAP) allows invoking operations
SOAP defines an XML-based format for parameters
SOAP requests/responses can ride on:
HTTP
The most common case today
SMTP or MSMQ
For loosely-coupled interactions
Other protocols

11. What SOAP Provides Industry agreement Object model independence
It’s endorsed by Microsoft, IBM, Sun, Oracle, BEA, Iona, and others
Object model independence
SOAP isn’t tied to any operating system, programming language, or object model
Support for diverse protocols
Synchronous and asynchronous

12. Illustrating A SOAP Message
Envelope
Headers
Body
Method
Parameters

13. An Example SOAP Request (1)
POST /AccountAccess HTTP/1.1
Host:
Content-Type: text/xml; charset=“utf-8”
Content-Length: 305
SOAPAction:
<SOAP-ENV:Envelope
xmlns:SOAP-ENV =
"
SOAP-ENV:encodingStyle =
"

14. An Example SOAP Request (2)
<SOAP-ENV:Body>
<m:GetBalance
xmlns:m="
<Account> </Account>
</m:GetBalance>
</SOAP-ENV:Body >
</SOAP-ENV:Envelope>

15. An Example SOAP Response (1)
HTTP/ OK
Content-Type: text/xml; charset="utf-8"
Content-Length: 304
<SOAP-ENV:Envelope
xmlns:SOAP-ENV =
"
SOAP-ENV:encodingStyle =
"

16. An Example SOAP Response (2)
<SOAP-ENV:Body>
<m:GetBalanceResponse
xmlns:m="
<Balance>3,822.55</Balance>
</m:GetBalanceResponse>
</SOAP-ENV:Body >
</SOAP-ENV:Envelope>

17. Discovering Web Services: UDDI
Universal Description, Discovery, and Integration (UDDI) provides a specialized directory service for discovering compatible web services
It uses XML
It’s endorsed by Microsoft, IBM, Ariba, Oracle, Sun, BEA, and more
An organization can create an XML-defined business registration
Which can contain information about various available web services

18. Illustrating A UDDI Business Registration
Name: QwickBank
Description: Internet Bank
Contacts:
Business Entity
Business Service
Name : Account access
Binding Template: URL 1, tModel x
Binding Template: URL 2, tModel y

19. The Trouble With UDDI (2000)
It’s complicated
Microsoft’s .NET Framework ships a simpler discovery mechanism called Disco for use on intranets
It’s not being used for web services yet
Many businesses are registered, but not many WSDL definitions
Without WSDL, developers can’t build interoperable web services clients

20. Introduction to Web Services in the Microsoft .Net Framework

21. ASP.NET The next generation of ASP (Active Server Pages)
It looks similar, but it’s actually very different
Allows creating two kinds of applications:
Browser applications
Rely on .aspx pages
Web services applications
Rely on .asmx pages

22. Illustrating a Web Services Application
IIS
class X {
[WebMethod]
public int
Method1()
{ … } }
SOAP
app.asmx
ADO.NET
Common Language Runtime
DBMS

23. Exposing Web Services: An Example .asmx Page (1)
WebService Language="c#" Class="Compute" %>
using System.Web.Services;
public class Compute {
[WebMethod] public int Factorial(int f)
int i;
int result = 1;
for (i=2; i<=f; i++)
result = result * i;
return result; }

24. Exposing Web Services: An Example .asmx Page (2)
[WebMethod] public double SquareRoot(double s) {
return System.Math.Sqrt(s); }

25. XML Web Services Protocol Stack
Internet Protocols
Directory of services: UDDI
Service discovery: DISCO
Microsoft specific ?
Service descriptions: WSDL
Service interactions: SOAP
Universal type system: XSD
Universal data format: XML
Ubiquitous communication: Internet

26. The .NET Framework provides a bi-directional mapping
Web Services
The .NET Framework provides
a bi-directional mapping
Application
Concepts
Web
XML
XSD
WSDL
SOAP
Framework
Objects
Classes
Methods
Calls
Data
Schema
Services
Invocation

27. Web Services with .NET public class OrderProcessor{
public void SubmitOrder(PurchaseOrder order) {...} }
public class PurchaseOrder
public string ShipTo;
public string BillTo;
public string Comment;
public Item[] Items;
public DateTime OrderDate;
public class OrderProcessor {
[WebMethod]
public void SubmitOrder(PurchaseOrder order) {...} }
[XmlRoot("Order", Namespace="urn:acme.b2b-schema.v1")]
public class PurchaseOrder
[XmlElement("shipTo")] public string ShipTo;
[XmlElement("billTo")] public string BillTo;
[XmlElement("comment")] public string Comment;
[XmlElement("items")] public Item[] Items;
[XmlAttribute("date")] public DateTime OrderDate;
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope>
<soap:Body>
<SubmitOrder>
<Order date=" ">
<shipTo>Manuel Costa</shipTo>
<billTo>Bill Gates</billTo>
<comment>Overnight delivery</comment>
<items>
<productId> </productId>
<description>Dom Perignon</description>
</items>
</Order>
</SubmitOrder>
</soap:Body>
</soap:Envelope>
Order order = new Order();
order.ShipTo = "Manuel Costa";
order.BillTo = "Bill Gates";
order.OrderDate = DateTime.Today; …
OrderProcessor.SubmitOrder(order);

28. A Web Services Example: Microsoft’s .NET My Services

29. A Web Services Example: Microsoft’s .NET My Services
.NET My Services is a set of Internet-accessible web services that store data about users
The data is described using XML
Applications can access that data
Access is via SOAP
Users control which applications are allowed to access which parts of their data

30. Illustrating .NET My Services
Applications
Clients
Internet

31. Describing .NET My Services
Passport
Based on Kerberos
.NET Alerts
.NET Services
.NET Contacts
.NET Locations
.NET Calendar
More

32. A .NET My Services Request
SOAP request:
- Service name
- PUID
- Kerberos ticket
- Method(Parameters)
.NET My Services Applications
.NET My Services
SOAP response

33. .NET Services (Mark) .NET Contacts (Mark) Passport Service
5) Locate Mark’s .NET Contacts service
.NET Services (Mark)
6) Look up Bob’s contact information and get his PUID
.NET Contacts (Mark)
4) Get tickets for .NET My Services services
7) Locate Bob’s myNotifications service
Passport Service
.NET Services (Bob)
Booking Application
1) Log in as Mark
2) Get ticket for application
8) Send notification to Bob
3) Request seats and invite Bob
.NET Alerts (Bob)
9) Deliver notification to Bob
.NET Locations (Bob)

34. Creating a Web Service in Visual Studio .Net

35. Creating a ASP.NET Web Service Project

36. Changing the Web Service Name

37. Accessing the Code Behind

38. Understanding the Code Behind
inheritance is optional (useful to create state full web services)

39. Editing the Code Behind
attribute that tells that this method should be exposed as a web service method

40. Understanding the .asmx page
In this case, everything is in the code behind

41. Build

42. Files Generated

43. Testing with a Browser

44. Viewing the dynamically generated WSDL (1)

45. Viewing the dynamically generated WSDL (2)

46. Consuming a Web Service in Visual Studio .Net

47. Creating a ASP. NET Web Application

48. Adding a Reference to the Web Service

49. Viewing the Proxy Class Created Behind the Scenes

50. Designing the web page

51. Calling the web service

52. Running the client application

53. Sources Seminário "Understanding .Net", David Chappell, FEUP, 2000
Seminário "Introduction to .NET", Manuel Costa, FEUP, 2001