WEB 服务初级编程

1. WEB服务初级编程 祝伟华 网络新型服务技术中心

2. 内容 • 分布式计算 • 互联网分布式计算标准 • 定义 • 发布 • 使用 • 其它特性

3. 分布式计算 • Procedure Call • Remote Procedure Call (RPC) • Tuxedo • CORBA • RMI/IIOP/EJB • 基于浏览器客户端分布式计算 • Rich Client • JAVA APPLET • JAVASCRIPT/AJAX • COM/COM+/DNA • Web Service/SOAP/SOA

4. Internet 互联网分步式计算 Devices,Browsers Vertical andportal service Access Application Call Services Application App-specificWeb Service Building blockWeb Service OS andlocal services Web ServicesContract

5. 基于互联网分布式计算标准 • HTTP • XML • SOAP (Simple Object Access Protocol) • Web Service Description Language (WSDL) • DISCO • UDDI (Universal Discovery, Description, and Integration )

6. Request disco Discovery Return disco (XML) Request WSDL Description Return WSDL (XML) Request .asmx Protocol Return response (XML) WEB服务架构 Web Service Web Service Client

7. 定义 • WebService Directive (页面定义) • Settings for ASP.NET compilers <%@ WebService Language=value Class=value %> • WebMethod Attribute (后台代码定义) • 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 ]...

8. 定义 <%@ 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; }}

9. 发布 • Expose Web Service and Web Service methods • Create a Web Service proxy and an assembly • Generate proxy with WebServiceUtil 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 • 思考: 代理类, SOAP协议间数据如何传递和转换?

10. 发现 • .disco 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 WebServiceUtil tool • Automatically created by Visual Studio.NET • Global directory of Web Services through UDDI • Universal Discovery, Description, and Integration (http://www.uddi.org)

11. 使用 Web ServiceDeveloper Web ApplicationDeveloper Web Server 1 Service App asmx .aspx Web Server 2 Service App Proxy Web Form

12. 使用 • Create client proxy class • Input: • WSDL contract • Proxy language and protocol • Output: • Single source file in specified language, containing: • Proxy class • Code for network invocation and marshalling • Command-line example: • webserviceutil /c:proxy /l:C# /namespace:MathServiceSpace MathService.sdl

13. 使用 • 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 “?SDL” • Formal WSDL description of Web Service • XML-based grammar • Can be used as input for WebServiceUtil.exe

14. 使用 (通过HTTP协议) • Web Services are URL addressable • 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

15. 使用 (HTTP/GET/POST) • http://server/appl/service.asmx/method?param=value • 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

16. 使用 (HTTP/SOAP调用) • 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

17. WSDL • 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 • WSDLcontract • Core Elements of WSDL • service, port, and portType • operations and messages

18. WSDL <definitions name=“serviceName“> <import namespace=“http://namespacePath“ location=“http://path/fileName.wsdl“> <portType name=“portNameType“> <operation name=“opName“> <input message=“msgNameInput“ /> <output message=“msgNameOutput“ /> </operation> </portType> <binding> <soap:operation soapAction=“http://...“ /> </binding> <service name=“serviceName“> <port name=“portName“ binding=“bindingName“> <soap:address location="http://..." /> </port> </service></definitions>

19. 高级特性 • 状态管理 • 安全性 • 事务处理

20. SOA • Service Oriented Architecture • EAI (Enterprise Application Integration)