Pengantar Teknologi Web 2

Web Architectures & Technologies
WWW
• Software
• Kumpulan service Internet, yaitu web-web yang berada di layer aplikasi
• Ditemukan oleh Tim Berners-Lee dkk di CERN
• Didesain untuk membantu para ilmuwan di CERN untuk memperoleh informasi dari dokumen-dokumen di Internet
• Tujuannya: membuat software (browser) untuk menampilkan informasi tersebut
– Idenya: hyperlink
WWW
• The world wide web consortium (W3C) definition of the web: "The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge"
• Provides information access in ways not previously possible
– Hyperlinked (Hypertext)
– Graphical user interface
– Pictorial and non-text information
– Information that changes rapidly
– Immediate access
– Anyone can author a web site
– Multi-user access to the same information (try that with a book)
– Easily searchable information
WWW Components
• Structural Components
– Clients/browsers – to dominant implementations
– Servers – run on sophisticated hardware
– Caches – many interesting implementations
– Internet – the global infrastructure which facilitates data transfer
• Semantic Components
– Hyper Text Transfer Protocol (HTTP)
– Hyper Text Markup Language (HTML)
• eXtensible Markup Language (XML)
– Uniform Resource Identifiers (URIs)



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Web Architecture
• Layering Aspect
– “Separation of concerns”
– How many concurrent users are you serving?
– Shared needs among multiple applications? (e.g., security)
• Data Aspect
– What kind(s) of data are you delivering?
• Structured vs non structured
• On-demand vs. real-time
– What are the bandwidth requirements?
• Size & nature of data
• Again, audience concerns
Tiers…?
• A “tier” can be hardware, software, or logical. The last is the most sensible option from an architectural viewpoint.
• Therefore:
– A non-application-specific client (such as a web browser) is not a tier
– A database with no overlying data access layer is not really considered a tier either











the three roles
• the Model contains data that represents the problem
• the Controller responds to user actions by telling the Model how to change
• the View displays the current state of the Model to the user
how do we design it?
• the Model is a class that represents the actual problem being solved
– it has private fields, and provides accessor (getter and setter) methods
– the Model should always be a separate class
• if using a GUI
– the listeners collectively are the Controller
– the displayed components are the View
– the Controller and View are thus a little bit interdependent
Combining Controller and View
• Sometimes the Controller and View are combined, especially in small programs
• Combining the Controller and View is appropriate if they are very interdependent
• The Model should always be independent
• Never mix Model code with GUI code!
– why?
• ANSWER: you may be required to change the View
• if you keep View and Model separate, changing the View will be relatively simple






MVC Separation
• Separating the presentation from the model
– Presentasi dan model memiliki fokus yang berbeda:
• presentasi ke tampilan, model ke data.
– Perbedaan ketergantungan:
• presentasi bergantung pada model tapi tidak sebaliknya.
– Sehingga dapat mengembangkan multiple presentation dengan model yang sama
• Separating the controller from the view
– Contoh: .NET Web application
– File: *.aspx dan *.aspx.vb
• Contoh: PHP Zend Framework, Code Igniter





Planning A Web site
• Purpose
– Purpose and Goal
– Target Audience
– New Web Technologies
– Web site comparison
• Content
– Value-added contents
– Text
– Images
– Color Palette
– Multimedia