Introduction to Web Engineering

Introduction to Web EngineeringBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.1OutlineIntroduction to the CourseWhat is web engineering?Web applicationsThe case for web engineeringCategories of web applicationsCharacteristics of web applicationsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.21. Introduction to the CourseThis course aims: to introduce the methods and techniques used in Web-based application development to develop practical web applicationsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.31.1 Web engineering methods and techniques This modules includes the following topics:Web application development approachesProcess models Web project managementProduct developmentRequirement engineeringWeb application modelingWeb application architecturesTechnologies and toolsTesting web applicationsMaintenance Quality Aspects:SecurityBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.41.2 Web application developmentBrowser interprets user’s selection and makes request from appropriate serverServer accepts and processes request from browser4. Server sends requested files to browser to be interpreted1. User sends requestUser receives file displayed by the browserBrowserBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.51.2 Web application development Hyper-text Markup Language (HTML)Cascading Style-sheets (CSS) Client-side Scripting Language (JavaScript)Serve-side Scripting Language (PHP)Database Language (MySQL)Basharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.61.3 BooksWeb Engineering, by Gerti Kappel, Birgit Proll, Siegfried Reich, Werner Retschitzegger, John Wiley & Sons; ISBN: 3-89864-234-8Beginning HTML, XHTML,CSS and JavaScript, by Jon Duckett, Wiley Publishing; 2009, ISBN: 978-0-470-54070-1. Beginning PHP programming, by Matt Doyle, Wrox publishers, 2009, ISBN: 0470413964 Reference books:Learn JavaScript, by Chuck Easttom, Wordware Publishing; 2002, ISBN 1-55622-856-2Beginning PHP and MySQL by W. Jason Gilmore, Apress publisher, 4th edition; 2010, ISBN-13 (electronic): 978-1-4302-3115-8.Basharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.72. Web engineeringSoftware engineering is an engineering discipline that is concerned with all aspects of software production Software Engineering is the science and art of building significant software systems that are:on timeon budgetwith acceptable performancewith correct operationBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.82. Web engineeringWeb engineering is the study of the process, used to create high quality Web-based applications Web engineering draws heavily on the principles and management activities found in software engineering processesWeb engineering extends Software Engineering to Web applicationsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.92. Web engineeringThe application of systematic and quantifiable approaches to cost-effective analysis, design, implementation, testing, operation, and maintenance of high-quality web applicationsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.103. Web applicationsWWW has massive and permanent influence on our livesEconomy, Industry, education, healthcare, entertainmentWhy? global and permanentComfortable and uniform accessBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.113. Web applicationsWWW started as an informational mediumEvolved into application mediumInteractive, data intensive servicesDistinguishing factorsHow it is used?Technologies and standards for developmentBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.123. Web applicationsA Web application is a system that utilizes W3C standards & technologies to deliver web-specific resources to clients (typically) through a browserTechnology + interactionBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.134. The case for web engineeringApplication development on the Web remains largely ad hocunplanned, one-time eventsIndividual experienceLittle or no documentation for code/designShort-term savings lead to long-term problems in operation, maintenance, usability, etc.lack of performance, reliability, user-freindliness and scalability Because Web apps are so interdependent, the problem is compoundedBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.144. The case for web engineeringRoot Causes of poor design:Development as an authoring activityDevelopment is “easy”Techniques that should not be used are misappliedTechniques that should be used are not appliedBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.154. The case for web engineeringTop project drawbacks (Cutter, 2000)84% - Failure to meet business objectives79% - Project schedule delays63% - Budget overrun53% - Lack of functionalityWeb Engineering’s solution:Clearly defined goals & objectivesSystematic, phased developmentCareful planningIterative & continuous auditing of the entire processBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.165. Categories of web applicationsDocument-centric webInteractive and transactional web applicationsWorkflow-based web applicationsCollaborative and social web applicationsPortal-oriented web applicationsUbiquitous web applicationsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.175.1 Document-centric web sitesoriginator to Web applicationsStatic HTML documentsManual updatesProsSimple, stable, short response timesConsHigh management costs for frequent updates & large collectionsMore prone to inconsistent/redundant infoExample: static home pagesBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.185.2 Interactive & transactionalNot only read-only content but also allow content modificationCome with the introduction of HTML formsSimple interactivityDynamic page creationWeb pages and links to other pages generated dynamically based on user inputBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.195.2 Interactive & transactionalContent updates -> TransactionsDatabase connectivityIncreased complexityExamples: news sites, booking systems, online bankingBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.205.3 Workflow-based applicationsDesigned to handle business processes across departments, organizations and enterprisesAutomates processes consisting of series of stepsBusiness logic defines the structureHigh complexity; autonomous entities Examples: B2B and e-GovernmentBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.215.4 Collaborative & social webUnstructured, cooperative environmentsSupport shared information workspaces to create, edit and manage shared informationInterpersonal communication is paramountClassic example: WikisThe Social WebUnrecognizability traditionally characterized WWWMoving towards communities of interestExamples: Blogs, facebook, twitter etc.Basharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.225.5 Web portalsOne specially-designed at a website which brings information together from diverse sources in a uniform wayEach information source gets its dedicated areaSpecialized portalsBusiness portals Marketplace portals Community portalsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.235.6 Ubiquitous web applicationsCustomized services delivered anywhere via multiple devicesStill an emerging fieldBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.245.7 Categories of Web Applications (development history vs complexity)Doc-CentricInteractiveTransactionalWorkflowBased Social WebCollaborativeUbiquitousPortalOrientedDevelopment HistoryComplexityBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.256. Characteristics of Web ApplicationsHow do Web applications differ from traditional applications?3 dimensions Product-basedUsage-basedDevelopment-basedBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.266.1 Product-based characteristicsProduct-related characteristics constitute the “building blocks” of a Web applicationContent:Document character & multimediaQuality demands: current, exact, consistent, reliableBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.276.1 Product-based characteristicsNavigation Structure (Hypertext):Non-linearityPotential problems: Disorientation & cognitive overloadUser interface (Presentation):Appearance Self-explanationBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.286.2 Usage-based characteristics Much greater diversity compared to traditional non-Web applicationsUsers vary in numbers, cultural background, devices, h/w, s/w, location etcSocial Context (Users):Spontaneity - scalabilityHeterogeneous groupsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.296.2 Usage-based characteristics Technical Context (Network & Devices)Quality-of-ServiceNatural Context (Place & Time):GlobalityAvailabilityBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.306.3 Development-based characteristicsThe Development Team:Multidisciplinary – print publishing, s/w development, marketing & computing, art & technologyTechnical Infrastructure:Lack of control on the client sideBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.316.3 Development-based characteristicsIntegration:Internal: with existing legacy systemsExternal: with Web servicesIntegration issues: correct interaction, guaranteed QoSBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.32SummaryWeb engineering extends Software Engineering to Web applicationsWhy web engineering?Web applicationsCategories and characteristics of web applicationsBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.33ReferencesLecture Slides by Kappel et al. Chapter 1, Kappel, G., Proll, B. Reich, S. & Retschitzegger, W. (2006). Web Engineering, 1st ed. Hoboken, NJ: Wiley & SonsUNESCO ICTLIP Module 6. Lesson 1 SlidesBasharat Mahmood, COMSATS Institute of Information Technology, Islamabad, Pakistan.34