1. Web Services Overview

2. Objectives Background Web Services Overview Microsoft® .NET Framework
Microsoft ASP.NET
Web Services Overview
Concepts and Architecture
Design and Create Web Services
Consume Web Services

3. Contents Section 1: Overview Section 2: Architecture
Microsoft .NET framework and ASP.NET
Section 3: Creating Web Services
Section 4: Using Web Services
Invoking and consuming Web Services
Section 5: Advanced Web Services
State Management, Security, and Transactions
Summary

4. Section 1: Overview “Looking Back ...“ What are Web Services?
Distributed Web applications

5. Looking Back ... Traditional distributed computing
Client/server model
Distributed object model
Components: packaging and interoperability
Remoting: remote method invocation
COM, CORBA, Java RMI and EJB
Microsoft Windows DNA
Distributed interNet Application Architecture
DHTML, COM, ASP, Message Queuing
The interactive Web

6. What’s Wrong with That?
Distributed object models don‘t scale to the Internet
Tightly coupling service and consumer
Need for homogeneous infrastructure
Versioning problems
Limited COM support on non-Windows platforms
CORBA is a remoting architecture
CORBA Component Model
Server object implementation not portable
EJB—Enterprise JavaBeans
The purely interactive Web

7. Web Services—Basics Expose services to other processes Black boxes
Internet or intranet
Black boxes
Component-like, reusable
Based on the .NET Framework
ASP.NET Web Services model
Based on open standards
HTTP, XML, and SOAP

8. Web Services—Basics Interconnect
Applications
Different clients
(M)any device
Distribution and integration of application logic
Web Services are loosely coupled
Enable the programmable Web
Not just the purely interactive Web

9. Distributed Web Applications
Devices, Browsers
Vertical and portal service
Access Application
Call Services
Internet
Application
App-specific Web Service
Building block Web Service
OS and local services
Web Services Contract

10. Section 2: Architecture
The .NET Framework Architecture
Programming Model
Configuration

11. The .NET Framework Architecture
Microsoft .NET Framework
System Services
Common Language Runtime
ASP.NET
Web Forms
Web Services
Windows Forms
Services Framework
Base
Data
Debug
...

12. Programming model CIL & Metadata Source Code Compiler
Common Language Runtime
Execution Engine
Class Lib
Class Loader
JIT Compiler
Managed native Code
Execution

13. Configuration 1/2 Concepts and architecture Web.Config file
Hierarchical configuration architecture
Influence on the actual directory and all subdirectories
Root
Dir
Web.Config
Sub
Dir1
Sub
Dir2

14. Configuration 2/2 Web.Config file WebServicesConfiguration class
XML based
File is kept within the application directory
Default and custom configuration
Customized Web.Config file
Customized configuration section handler
WebServicesConfiguration class
Contains configuration information
<webServices> section in Web.Config

15. Section 3: Creating Web Services
Basics of Creating Web Services
Web Services Infrastructure
Code and Syntax
Web Services Namespace
Publishing
Discovery

16. Creating Web Services—Basics
.asmx file
Virtual path of ASP.NET Web application
Stand-alone or part of an existing solution
Web Services infrastructure
Discovery, description, and wire format
Microsoft Visual Studio.NET
Microsoft Visual Basic.NET, C#, and Managed C++

17. Web Services Infrastructure
Client
Discovery
Request .vsdisco
Return disco (XML)
Web Service
Description
Request WSDL
Return WSDL (XML)
Protocol
Request .asmx
Return response (XML)

18. Code and Syntax WebService Directive WebMethod Attribute
Settings for ASP.NET compilers
WebService Language=value Class=value %>
WebMethod Attribute
Code Declaration Syntax
Outline
Inline (in C#)
WebService Class=“MyClass.MyWebService“ %>
WebService Language=“C#“ Class=“MathService“ %> using System.Web.Services; public class MathService : WebService { [ WebMethod ] ...

19. Sample .asmx file
WebService Language=“C#“ Class=“MathService“ %> using System; using System.Web.Services; public class MathService { [WebMethod] public int Subtract(int a, int b) { return a - b; } public int Subtract_vs(int a, int b) { return b - a; } }

20. System.Web.Services Namespace 1/2
Base class for Web Services
Provides base functionality
For example, WebService.Session
WebServiceAttribute
Optional class to add additional information
WebMethodAttribute
[ WebMethod ]
Makes a method a Web Service method

21. System.Web.Services Namespace 2/2
WebServiceBindingAttribute
Interface in WSDL
Set of operations
WebServicesConfiguration
Contains configuration information
<webservices> section in config.web
WebServicesConfigurationSectionHandler

22. Publishing a Web Service
Expose Web Service and Web Service methods
Create a Web Service proxy and an assembly
Generate proxy with WSDL tool
Create an assembly
Enables developers to program against Web Services
Publish WSDL contract and HTML description
Web Service clients
Can be Web applications or browsers

23. Discovery of Web Services
.vsdisco file
XML-based file
containing links to resources for retrieving WSDL
Stored in the server‘s root directory
Access via URL and dynamic discovery document
Start discovering with the Disco tool
Automatically created by Visual Studio.NET
Global directory of Web Services through UDDI
Universal Discovery, Description, and Integration (

24. Disco.exe Discovering Web Services Command-line example:
disco /out:location /domain:domain /username:username /password:password WebService1.vsdisco

25. WSDL.exe Web Services Description Tool Input: Output:
Create client proxy class
Input:
URL of a WSDL file, Proxy language, and protocol
Username and password
Output:
Single source file in specified language, containing:
Proxy class
Code for network invocation and marshalling
wsdl /l:C# /protocol:protocol /out:filename /namespace:MathServiceSpace MathService.sdl

26. Section 4: Using Web Services
Application Model
Invoking Web Services
Consuming Web Services
Web Services Description Language (WSDL)

27. Web Application Developer
Application Model
Web Service Developer
Web Application Developer
Web Server 1
Service App
asmx
.aspx
Web Server 2
Service App
Proxy
Web Form

28. Invoking Web Services Web Services are URL addressable Protocols
HTTP request
Protocols
HTTP-GET
Method name and arguments in URL
HTTP-POST
Method name and arguments in POST body
HTTP-SOAP
XML grammar for
Addressing the Web Service
Returning results

29. Invoking: HTTP-GET and HTTP-POST
Standard HTTP-GET
Method name = PATHINFO
Method arguments = URL query string
Query string key = parameter name
Multiple parameters
Only primitive .NET runtime data types
Result is an XML document
Any .NET data type
HTTP-POST
Similar to GET, but with arguments in the form body

30. Invoking: HTTP-SOAP XML grammar for
Web Service method, method parameters, results
Supports all standard .NET data types and value classes
Additionally: classes, structs, datasets
Class and struct marshalling
Serialization in XML format

31. Consuming Web Services
Request without method name and parameters
HTML description of Web Service
Service capabilities, methods, protocols
Web Service can return WSDL
HTTP-GET, HTTP-POST, and HTTP-SOAP
Request with parameter “?WSDL”
Formal WSDL description of Web Service
XML-based grammar
Can be used as input for WebServiceUtil.exe

32. WSDL 1/2 XML grammar, defining:
Services and ports that communicate via messages
Binding
Specify a protocol or a data format for a message or a port
Extensions for SOAP 1.1, HTTP GET/POST, and MIME
Public description of a Web Service and its content
WSDL contract
Core Elements of WSDL
service, port, and portType
operations and messages

33. WSDL 2/2 An abstract illustration of WSDL elements service_1 port_C
message
port_A
port_D
port type
port_C
port_B

34. Sample WSDL file
<definitions name=“serviceName“> <import namespace=“ location=“ <portType name=“serviceNamePortType“> <operation name=“opName“> <input message=“msgNameInput“ /> <output message=“msgNameOutput“ /> </operation> </portType> <binding name=“serviceNameSoapBinding“> <soap:operation soapAction=“ /> </binding> <service name=“serviceName“> <port name=“serviceNamePort“ binding=“bindingName“> <soap:address location=" /> </port> </service> </definitions>

35. Section 5: Advanced Web Services
State Management
Security
Transactions
Execution Model
Distributed Web Applications

36. State Management Web Services are stateless
Use, for example, ASP.NET session state
What is a session?
Restricted to a logical application
Context in which a user communicates to a server
Functionality
Request identification and classification
Store data across multiple requests
Session events
Release of session data
.NET State Server

37. Security Model Reasons for Security Security Configuration
Prevent access to areas of your Web server
Record and store secure relevant user data
Security Configuration
Authentication, Authorization, Impersonation
Code Access Security
Walks the call stack to check authorization
Web
Client OS
ASP.NET
App
IIS
.NET

38. Transactions 1/2 Like ASP.NET Web Forms COM+ Services
COM+ automatic transactions
Atomic, consistent, isolated, durable (ACID)
SQL Server
COM+ transaction context
Application
Web Service
Message
Queuing
Server

39. Transactions 2/2 TransactionOption Property on WebMethod Attribute:
[WebMethod(TransactionOption= TransactionOption.Required)]
Transaction Modes
Disabled
Supported
NotSupported
Required
RequiresNew

40. Execution Model Synchronous Asynchronous
Like any other call to class methods
Asynchronous
.NET Framework design pattern
Split the method into two code blocks
BeginMethodName
EndMethodName
Client has to call Begin and End
Pass a callback function or
WaitHandle class

41. Using Web Services from UI
Completely separate layout and processing logic
Two (or more) files: .aspx and .aspx.cs or .aspx.vb
Files for designers and files for programmers
Easy maintainability of your application
.aspx
.aspx.cs

42. Sample .aspx .asmx file implements method “Add”
WSDL file, returned by the ASP.NET runtime
Import Namespace=“MathServiceSpace“ %> <script language=“C#“ runat="server"> public void Submit_Click(Object S, EventArgs E) { service.Add(operand1, operand2); </script> <input OnServerClick=“Submit_Click“ runat="server" ...>

43. Sample C# proxy class, generated by WSDL.exe
[System.Web.Services.Protocols. SoapDocumentMethodAttribute(“ public int Add(int a, int b)
{ object[] results = this.Invoke(“Add“, new object[] {a, b}); return (int)(results[0]); } public System.IAsyncResult BeginAdd(... public int EndAdd(...

44. Summary .NET Architecture Overview Web Services and ASP.NET
Create and Publish Web Services
Invoke and Consume Web Services
WSDL and Proxy Classes
Program Against Web Services

45. Questions

46. ASP.NET QuickStart Tutorial
A Simple Web Service
ASP.NET QuickStart Tutorial

47. ASP.NET QuickStart What Is It? Installation .NET Framework Samples
Tutorial, ASP.NET samples
Syntax, architecture, features
Installation
Install Microsoft .NET Framework SDK
Visual Studio.NET installation and Components Update
Installation of Visual Studio.NET is not mandatory
.NET Framework Samples
ASP.NET QuickStart  ASP.NET Web Services  Writing a Simple Web Service

48. Building a Simple Web Service
Create your own MathService
.asmx
Implement class MathService and Web methods
Create WSDL file (MathService.wsdl)
Request to MathService.asmx
Generate C# proxy class (MathService.cs)
WebServiceUtil.exe
Generate Assembly (MathService.dll)
C# compiler “csc”

49. Consuming a Simple Web Service
Implement MathService client (MathServiceClient.aspx)
ASP.NET UI
Operands  Text box
Methods  Buttons
Result  Label
Event Handler
OnServerClick

50. TerraServer. Microsoft.net

51. Overview What is it? Assumptions for this tutorial Set of Web methods
Programmable interface to online database
Aerial imagery and topographical maps
Assumptions for this tutorial
Visual Studio.NET
Internet connection

52. Tutorial Create a new project Create application UI Add Web reference
Implement functionality

53. Legal Notices
Unpublished work. Ó 2001 Microsoft Corporation. All rights reserved.
Microsoft, Visual Basic, Visual Studio, and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.
The names of actual companies and products mentioned herein may be the trademarks of their respective owners.