world wide web万维网英文课件：ch15-Introduction to Rails.ppt

Chapter 15 Introduction to Rails 15.1 Overview of Rails Rails is Ruby based “A development framework for Web-based applications” Rails uses the Model-View-Controller architecture Model classes are the data classes, including constraint enforcement View classes present the data to the user Controller classes perform computations and deal with user interaction Rails uses an Object-Relational Mapping approach to working with databases A cars table corresponds to a car class The rows of the table correspond to instances of the class The correspondence is built automatically by the Rails framework Rails uses a combination of Ruby code and template files to create responses 15.1 Developer Tasks Design and build the model, including a database for storing model data Design and implement actions Design and implement the views 15.2 Document requests The Rails framework provides much of the superstructure necessary for a web application Scripts with the Rails framework set up the basic structure The first Rails example serves a single static document 15.3 Project Setup The InstantRails package provides all the components needed to develop and test Rails projects on a Microsoft Windows platform Start the InstantRails console InstantRails Set up a rails application rails rails1 Generate a controller ruby script/generate controller say Run the default server ruby script/server The server runs for a particular application 15.3 Project Directory Structure 15.2 Project Components A controller class, SayController, in the controllers directory The controller class has method named hello An html template file (static for this example) named hello.rhtml in directory views\say The Rails framework associates these components by the name ‘say’ 15.2 Request Processing 15.2 Dynamic Documents The next example displays the greeting but also displays the current time Uses Time.now from the Ruby library % … % embeds Ruby code in template files %= … % causes the value of the executed