Slide 1:B118 Web Programming Session #13 Forms, XML & Web Services May 3, 2004

Slide 2:Tonight’s Agenda Administrative Order form validation homework bEssentials Final exam Introduction to ASP.NET Web Server Controls XML Web Services

Slide 3:Administrative – Order Form Validation Grading criteria Solution discussion

Slide 4:Administrative – bEssentials Peer evaluations: based on contribution effort towards the team, showing up for meetings, meeting commitments for deliverables, etc. 5 percentage points out of the 30 percentage points for the project, proportional to the overall group score Allocate points from the pot to your team members:

Slide 5:Administrative – bEssentials Deliverables on the Final Exam day: Peer evaluation scores All files uploaded to Cypress On a single sheet of paper: Names of your team members URL of your company’s home page URL of any web pages that your team is especially proud of and would like to bring to my attention Anything else about your web site that you’d like to point out for grade evaluation Be prepared to do a 5 minute demo of your web site in front of the class before we begin the final exam

Slide 6:Administrative – Final Exam Bring Blue Book Review next class session

Slide 7:Introduction to ASP.NET Web Server Controls Basic controls (text box, radio button, check box) are similar to HTML controls Radio Button List & Check Box List ASP.NET controls do the grouping for you Retrieve list contents from a data source or list collection Dropdown List ASP.NET control uses same implementation model AutoPostBack attribute for immediate or deferred form processing Additional information: Chapter 4 of the text http://www.asp.net/Tutorials/quickstart.aspx, ASP.NET Web Forms topic

Slide 8:ASP.NET Validation Controls Does form validation in response to a button click event Required field (asp:RequiredFieldValidator) Range checking of input data (asp:RangeValidator) Verify the input data against a format such as email address, Social Security Number or minimum character length (asp:RegularExpressionValidator) Compare two data from two form controls (asp.CompareValidator)

Slide 9:Example: form-demo.aspx Web Matrix Technique highlights Page properties: Events (lightening bolt): Load (double-click) to create Page_Load subroutine template Create ListItems for a list control by clicking on (…) icon in collections Programming techniques RadioButtonList1.SelectedIndex=-1 to deselect all items in the list See what happens when you: Set AutoPostBack = "False" Set CausesValidation = "True"

Slide 10:XML - Introduction Core technology for one of the hottest areas in IT today An essential, "must know" topic if you want to stay current in web programming An excellent format for packaging and communicating data between humans, machines or both Firewalls may block binary data, XML is text only so it doesn’t have any problems getting through

Slide 11:XML – Overview XML = eXtensible Markup Language But it’s really not a language It’s a standard format for writing your own language in a way that other people (and applications) can easily learn Resembles HTML, similar to XHTML in terms of grammar rules (nesting, end tags, attribute values in quotes, comments, etc.) Tag names are case sensitive!

Slide 12:XML’s Hidden Role in .NET XML’s most useful place isn’t in a web application you might create, rather it’s in the infrastructure supporting your web application Places where .NET makes use of XML: ADO.NET Data Access Configuration files like web.config Web Services Anywhere that .NET needs to store miscellaneous data such as the list of files to display in the AdRotator control

Slide 13:XML Basic Compare these two product catalog data files Consider code in the applications that read these data files. If you later decide to store an additional piece of information for each item (such as stock shelf number), how would you have to modify the applications? For the text file format, applications need to be modified, even if they don’t need to use the new information. For the XML file format, as long as the application looks for specific tags and doesn’t need to use the new information, it won’t need modification.

Slide 14:XML XML isn’t a replacement for a real database XML doesn’t have all of the mechanisms that a database package has (to enforce table relations or manage concurrency issues, for example) In addition to the XML document itself, there are two other components: Document Type Definition (DTD) or XML Schema (XSD) eXtensible Style Sheets (XSL) – optional for displaying the XML document

Slide 15:DTD Example

Slide 16:XML Schema Example

Slide 17:XML Facilities in .NET Handle XML as a special type of text file XmlTextWriter, XmlTextReader Text stream I/O (you need to construct tags by specifying element names) Good for storing simple blocks of data You need to keep track of the structure and the order of the element tags ( then then , for example) Maintains connection to the actual data

Slide 18:XML Facilities in .NET: XmlTextWriter Dim fs As New FileStream ("c:\myFile.xml", FileMode.Create) Dim w As New XmlTextWriter(fs, Nothing) w.WriteStartDocument() w.WriteStartElement("SuperProProductList")0 ‘ Write the first product w.WriteStartElement("Product") w.WriteAttributeString("ID", "", "1") w.WriteAttributeString("Name", "", "Chair") w.WriteStartElement("Price") w.WriteString("49.33") w.WriteEndElement() w.WriteEndElement() ‘ Close the root element w.WriteEndElement() w.WriteEndDocument() w.Close()

Slide 19:XML Facilities: XmlTextWriter (cont’d) Produces this XML file:

Slide 20:XML Facilities in .NET Handle XML as a collection of in-memory objects XmlDocument, XmlNode Makes the entire XML document structure available as an in-memory object You set values to node properties, order of the element tags is maintained for you Tag pairs ( ) handled for you Offers ability to search for content by element ID or element tag name A copy of the original data Similar in concept to ADO.NET DataSet

Slide 21:XML Facilities in .NET Handle XML as a special interface to relational data XmlDataDocument Lets you read an XML document and then bind it to ADO.NET data controls such as DataGrid

Slide 22:XML Facilities in .NET Process an XML document through XSL (to create an HTML document, for example) XmlTransform to generate the output stream Xml takes XmlTransform output to generate an HTML page

Slide 23:XML Demo Programs All of these programs use the rental.mdb from B188

Slide 24:Web Services - Introduction Why? The architecture for Internet applications is very similar to the client/server architecture of about five years ago: monolithic, a full-featured application containing a variety of services behind a single proprietary user interface

Slide 25:The Era of Monolithic Applications Single web application offering a comprehensive set of services such as a financial services site (with access to individual savings, credit card, insurance information and services)

Slide 26:Limitations of Monolithic Applications Take a lot of time and resources to create Often tied to specific platforms or technologies, can’t be easily extended or enhanced Difficult to get multiple applications to work together beyond just a hyperlink Units of application logic can’t easily be reused between applications (this is the next level above just sharing source code or object classes) You have to go through the complete, monolithic application even if all you want is a simple piece of information (such as your savings balance or the current loan rate for a specific program)

Slide 27:Components and the COM Revolution On the standalone desktop application level, Microsoft addressed these problems through their COM (component object model) technology which produced ActiveX controls A lot of the individual functional services inside of Word and Excel are available as ActiveX controls, for example Web Services offers the same re-usable and more easily accessible functionality over a networked environment

Slide 28:Web Services and the Programmable Web Web Services are individual units of programming logic that exist on a web server Built on open standards, not a platform-specific binary standard Think of it as being able to call classes/subroutines/functions over a network

Slide 29:eWeek – September 23, 2002 page 26H

Slide 30: Web Services Standards

Slide 31:WSDL XML-based Contains only the information for communication between a Web Service and client, nothing on the inner workings of the service Designed for reading by applications To see the WSDL for an ASP.NET Web Service, add ?WSDL to the query string: http://localhost/WebService/myWebService.asmx?WSDL

Slide 32:SOAP One of the three supported standards for the transmission of Web Service information (the other two being HTTP GET & HTTP PUT) HTTP GET/PUT sends information as simple name/value pairs, SOAP uses a well-formatted XML document

Slide 33:DISCO Web Services are available at a specific URL address. How do you let the world know about this address? What if you need to change the address? DISCO is a machine-readable "HTML page with links to Web Services" As long as your application knows how to find the site’s .disco file, it can then find all of the Web Services available at that site

Slide 34:UDDI Proposed by Microsoft, very new and not yet widely adopted Conceptually equivalent to a Yahoo! for web services Sits at the level above DISCO files. It’s a means for businesses to advertise all the Web Services they have The UDDI registry itself is a Web Service Details at http://uddi.microsoft.com

Slide 35:Communicating with a Web Service

Slide 36:Creating a Web Service Code a .asmx file _ Public Class GetTransactions Inherits WebService Put it through the WSDL compiler to generate a Visual Basic source file: wsdl.exe /language:vb http://localhost/rental-XMLWebSvc.asmx?WSDL Compile VB source file to generate proxy DLL vbc.exe /t:library /out:GetTransactions.dll /r:system.dll /r:system.web.dll /r:system.web.services.dll /r:system.xml.dll /r:system.data.dll GetTransactions.vb

Slide 37:XML & Web Services Demo Programs All of these programs use the rental.mdb from B188 Commercial web services WeatherByZipClient.aspx Calls a web service that returns current weather conditions for a given ZIP code GoogleAPIClient.aspx Calls a web service operated by Google