Web Application Development

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Web Application Development

• 2007-03-25

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Application Development

• Not practical to design and develop every new Web
  page from the ground up
• What is needed is additional infrastructure to
  facilitate Web development
• Separation of content and presentation
• Programmers
• Page designers

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Spectrum of Approaches

• Scripting
• Template
• Hybrid
• Framework

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Programmatic Approach

• The source associated with the page object
  consists mostly of code written in some scripting
  language
• PERL, Python, CGI
• Major drawback is the limits placed on creative
  input of page designers

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Template Approaches

• Template consists mostly of formatting structures
• Content is poured into the template
• Appeals to page designers
• Server-Side Includes
• Cold Fusion (CFML)

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Hybrid Approaches

• Combines scripting elements with template
  structures
• PHP, ASP, JSP
• Best of both worlds
• Developers worst nightmare
• Violates the principal of separation of content
  and presentation

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PHP

• PHP Hyptertext Preprocessor
• Code-centric hybrid
• Powerful
• Popular
• Used in conjunction with databases

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ASP

• Active Server Pages
• Microsoft effort
• Combines server side scripting with access to the
  a wide variety of OLE and COM objects
• VB nature makes it ill-suited for modern web
  applications

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Separation of Content from Presentation

• None of these approaches fulfills this need
• Essential to recognize that
• There is content or data (model)
• The way the data is displayed (view)

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Separation Benefits

• Application flexibility
• The choice of presentation modes should be
  separate from the choices made to access the data
• Model-View-Controller (MVC)
• Controller constructs the data model
• Controller picks the best way to present the data

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Division of Responsibility

• Programmers vs. Designers
• Have different orientations
• Have very different skill sets
• Web is too complicated for one person to know
  everything
• Faster development

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Frameworks

• Java Server Pages Model 2 (JSP Mod 2)
• Set of guidelines for using the MVC model
• Java Standard Tag Library
• Blueprints
• Struts provide a robust infrastructure for Model
  2 application development

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XML-Based Approaches

• Used as the foundation of the data model
• XML skeleton is constructed
• Data is added to the XML containers embedded
  within the HTML page
• Extensible Stylesheet Language (XSL)
• Very flexible

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XML Approaches Issues

• Complexity of XSL
• Failure to keep simple things simple
• Not robust enough
• Lack of programming ability