CSCE 740 Software Engineering Lecture 10 Rails Projects

CSCE 740 Software Engineering Lecture 10 Rails Projects Topics • Saa. S Readings: Saa. S book Ch 2, 4 February 24, 2014

Saa. S round 2 - Last Time § RAILS § Fig 2. 1 100, 000 view Finish-up Last Lecture Slides § Slides ? ? ? New § Summary of Rails § Client-server § HAML § HTTP & URIs § Cucumber § HTML & CSS § Capybara § HAML – 2– Next Time: CSCE 740 Spring 2014

Rails Summary from Last time 9. The MVC Architecture 10. Components of Rails 11. REST 12. a New Rails Project 13. Rails Application Dir 14. Rails Appl Directory II 15. Directory: app 18. Configuring a DB 19. Creating a DB 20. Starting Webrick 21. rails generate 22. Setting the Application Home Page 23. Rails Scaffolding 28. What’s Next? 29. Rails Summary 30. Active Record 16. HAML - lightweight 31. … CS 169 Saasbook: Fox and Patterson – 3– CSCE 740 Spring 2014

Chapter 2 Saa. S Architecture Review – 4– Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Review Fig 2. 3 – URI + HTTPmethod – 5– Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Fig 2. 4 50, 000 ft view – 6– CSCE 740 Spring 2014

Fig 2. 6 Refining Steps 2 and 3 – 7– Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Lamp § Early Saa. S sites were created using the Perl and PHP scripting languages, whose § availability coincided with the early success of Linux, an open-source operating system, and My. SQL, an open-source database. § Thousands of sites are still powered by the LAMP Stack—Linux, Apache, My. SQL, and PHP or Perl. – 8– Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Scalability – 9– Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Fig 2. 8 5, 000 ft view Refining Middleware – 10 – CSCE 740 Spring 2014

Architectures for Web Apps Left - page controller Sinatra Center top – front controller J 2 EE servlets Center bottom – PHP Right – MVC used by rails – 11 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Fig 2. 10 – 5, 000 ft view – 12 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

2. 6 500 Feet: Active Record for Models Active Record architectural pattern § a single instance of a model class (in our case, the entry for a single movie) corresponds to a single row in a specific table – 13 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

CRUD § Create a new row in the table (representing a new object), § Read an existing row into a single object instance, § Update an existing row with new attribute values from a modified object instance, § Delete a row (destroying the object’s data forever). – 14 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

2. 7 500 Feet: Routes, Controllers, and REST - In 2000, Roy Fielding proposed, in his Ph. D. dissertation, a consistent way to map requests to actions that is particularly well suited to a serviceoriented architecture. § identify the various entities manipulated by a Web app as resources, and § design the routes so that any HTTP request would contain all the information necessary to identify both a particular resource and the action to be performed on it. § In Rails, the route mappings are generated by code in the file config/routes. rb, – 15 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Fig 2. 12 Rake Routes Summary Operation Index (list) movies index Read (show) movie Display fill-in form new Method & URI action GET /movies/: id show GET /movies/new Create from filled-in form POST /movies create Display form to edit GET /movies/: id/edit Update movie PUT /movies/: id update Destroy movie DELETE /movies/: id destroy – 16 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Fig 2. 13 Restful vs non. Restful Login to site • Non-RESTful site - POST /login/dave • URI RESTful site - POST /login/dave Welcome page • Non-RESTful - GET /welcome • URI RESTful - GET /user/301/welcome Add item ID 427 to cart • Non-RESTful - POST /add/427 • URI RESTful - POST /user/301/add/427 – 17 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

View cart • Non-RESTful - GET / cart • URI RESTful - GET /user/301/cart Checkout • Non-RESTful - POST /checkout • URI RESTful - POST /user/301/checkout – 18 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

ELABORATION: REST vs. SOAP vs. WS-* SOA standards bodies created committees to develop standards for SOA interoperation. One approach resulted in a collection of elaborate protocols for Web Services including WS-Discovery, WS-Description, and others, sometimes collectively called WS-* and jokingly called “WS-Deathstar” by David Heinemeier Hansson, the creator of Rails. The competing SOAP standard (Simple Object Access Protocol) was a bit simpler but still far more complex than REST. By and large, practicing developers perceived SOAP and WS-* as overdesigned committee-driven standards burdened by the archaic design stance – 19 – Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014

Fig 2. 14 500 ft – Template views HAML Haml HTML %br{: clear => ’left’} <br clear=”left”/> %p. foo Hello <p class=”foo”>Hello</p> %p#foo Hello <p id=”foo”>Hello</p> . foo <div class=”foo”>. . . </div> #foo. bar – 20 – <div id=”foo” class=”bar”>. . . </div> Saasbook Fox, Armando; Patterson, David (2014 -01 -31). CSCE 740 Spring 2014