Why Rails and Design for an Applica5on

Transcription

1 Why Rails and Design for an Applica5on CITS3403 Agile Web Development Reference: Ruby et al, Chapter 5

2 First there was Ruby... Ruby is the interpreted scripting language for quick and easy objectoriented programming. It has many features to process text files and to do system management tasks (as in Perl). It is simple, straight-forward, extensible, and portable. Oh, I need to mention, it's totally free, which means not only free of charge, but also freedom to use, copy, modify, and distribute it. - Yukihiro Matz Matsumoto Slides 2009 Cara MacNish, 2011, 2012 Wei Liu, University of Western Australia

3 Then there was Basecamp... The killer app... Slides 2009 Cara MacNish, 2011, 2012 Wei Liu, University of Western Australia

4 Out of which came Rails... Developed as a plaiorm for Basecamp by David Heinemeier Hansson Danish student in Computer Science and Business Admin Copenhagen Business School released 2004 Google and O Reilly Hacker of the Year ranked 34th in Business people who maser now 2007 he predicted that 'the s5gma of being a Web programmer s5ll using Windows will increase'

5 Why use Rails? Ruby et al easier to develop, deploy and maintain web applica5ons framework of choice for wide range of Web 2.0 applica5ons Why the need? new technologies - eg. AJAX, RESTful growing frustra5on among developers with exis5ng frameworks eg Java, PHP,.NET hard to develop worse s5ll, harder to maintain want apps that will stand the test of 5me combine ease of use with so^ware engineering principles

6 So=ware Engineering Principles MVC Rails apps are implemented using Model-View-Controller (MVC) architecture pieces of applica5on interact in a standard way skeleton provided Tes5ng tes5ng support built in Rails automa5cally creates test stubs Object- oriented scrip5ng language (Ruby) power and conciseness of scrip5ng language for usual scrip5ng tasks easier to maintain (structure, modularity, re- use, etc)

7 So=ware Development Philosophies DRY (Don t Repeat Yourself) every piece of knowledge in a system should be expressed in just one place (usually determined by MVC) a change in one place doesn t mean rewri5ng in many other places Convention over Configuration sensible defaults for knicng together applica5on less code, less configura5on

8 Agile Programming Agile Manifesto ( Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan DRY, Conven5on over Configura5on, and Ruby make Rails a fast prototyping environment working code early in development cycle customer collabora5on evolving requirements what- if sessions (fun!)

9 The Depot ApplicaDon Shopping Cart applica5on many features of Rails development create maintenance pages link database tables handle sessions create forms unit tes5ng, security, page layout,... So^ware engineering approach: Incremental development rapid cycles: (par5al) requirements specifica5on, design, development, tes5ng, (client feedback)... repeat agile programming requires a development environment that easily accommodates change

10 Use Cases use case - statement about how some en5ty uses system two roles or actors - buyer and seller buyer browse products select some to purchase supply extra informa5on to create order seller maintain list of products determine orders awai5ng shipping mark orders as shipped (make scads of money and re5re to tropical island)

11 Page Flow Buyer Pages Page flow - mock up of main pages, naviga5on between them

12 Page Flow Seller Pages Note: many details s5ll vague (especially shipping)

13 Data What data are we going to be working with? no commitment yet to databases, tables, etc (some5mes flat file is appropriate)

14 Client Review Agile programming promotes frequent interac5on with client diagrams may have been developed with client present if not, check they match client s current concep5on of system requirements modify as appropriate agree on priori5es for implementa5on what components do you need to get prototype started what items are most concrete? next, data prototyping