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| 1 | +== Welcome to Rails |
| 2 | + |
| 3 | +Rails is a web-application framework that includes everything needed to create |
| 4 | +database-backed web applications according to the Model-View-Control pattern. |
| 5 | + |
| 6 | +This pattern splits the view (also called the presentation) into "dumb" templates |
| 7 | +that are primarily responsible for inserting pre-built data in between HTML tags. |
| 8 | +The model contains the "smart" domain objects (such as Account, Product, Person, |
| 9 | +Post) that holds all the business logic and knows how to persist themselves to |
| 10 | +a database. The controller handles the incoming requests (such as Save New Account, |
| 11 | +Update Product, Show Post) by manipulating the model and directing data to the view. |
| 12 | + |
| 13 | +In Rails, the model is handled by what's called an object-relational mapping |
| 14 | +layer entitled Active Record. This layer allows you to present the data from |
| 15 | +database rows as objects and embellish these data objects with business logic |
| 16 | +methods. You can read more about Active Record in |
| 17 | +link:files/vendor/rails/activerecord/README.html. |
| 18 | + |
| 19 | +The controller and view are handled by the Action Pack, which handles both |
| 20 | +layers by its two parts: Action View and Action Controller. These two layers |
| 21 | +are bundled in a single package due to their heavy interdependence. This is |
| 22 | +unlike the relationship between the Active Record and Action Pack that is much |
| 23 | +more separate. Each of these packages can be used independently outside of |
| 24 | +Rails. You can read more about Action Pack in |
| 25 | +link:files/vendor/rails/actionpack/README.html. |
| 26 | + |
| 27 | + |
| 28 | +== Getting Started |
| 29 | + |
| 30 | +1. At the command prompt, start a new Rails application using the <tt>rails</tt> command |
| 31 | + and your application name. Ex: rails myapp |
| 32 | +2. Change directory into myapp and start the web server: <tt>script/server</tt> (run with --help for options) |
| 33 | +3. Go to http://localhost:3000/ and get "Welcome aboard: You're riding the Rails!" |
| 34 | +4. Follow the guidelines to start developing your application |
| 35 | + |
| 36 | + |
| 37 | +== Web Servers |
| 38 | + |
| 39 | +By default, Rails will try to use Mongrel and lighttpd if they are installed, otherwise |
| 40 | +Rails will use WEBrick, the webserver that ships with Ruby. When you run script/server, |
| 41 | +Rails will check if Mongrel exists, then lighttpd and finally fall back to WEBrick. This ensures |
| 42 | +that you can always get up and running quickly. |
| 43 | + |
| 44 | +Mongrel is a Ruby-based webserver with a C component (which requires compilation) that is |
| 45 | +suitable for development and deployment of Rails applications. If you have Ruby Gems installed, |
| 46 | +getting up and running with mongrel is as easy as: <tt>gem install mongrel</tt>. |
| 47 | +More info at: http://mongrel.rubyforge.org |
| 48 | + |
| 49 | +If Mongrel is not installed, Rails will look for lighttpd. It's considerably faster than |
| 50 | +Mongrel and WEBrick and also suited for production use, but requires additional |
| 51 | +installation and currently only works well on OS X/Unix (Windows users are encouraged |
| 52 | +to start with Mongrel). We recommend version 1.4.11 and higher. You can download it from |
| 53 | +http://www.lighttpd.net. |
| 54 | + |
| 55 | +And finally, if neither Mongrel or lighttpd are installed, Rails will use the built-in Ruby |
| 56 | +web server, WEBrick. WEBrick is a small Ruby web server suitable for development, but not |
| 57 | +for production. |
| 58 | + |
| 59 | +But of course its also possible to run Rails on any platform that supports FCGI. |
| 60 | +Apache, LiteSpeed, IIS are just a few. For more information on FCGI, |
| 61 | +please visit: http://wiki.rubyonrails.com/rails/pages/FastCGI |
| 62 | + |
| 63 | + |
| 64 | +== Apache .htaccess example |
| 65 | + |
| 66 | +# General Apache options |
| 67 | +AddHandler fastcgi-script .fcgi |
| 68 | +AddHandler cgi-script .cgi |
| 69 | +Options +FollowSymLinks +ExecCGI |
| 70 | + |
| 71 | +# If you don't want Rails to look in certain directories, |
| 72 | +# use the following rewrite rules so that Apache won't rewrite certain requests |
| 73 | +# |
| 74 | +# Example: |
| 75 | +# RewriteCond %{REQUEST_URI} ^/notrails.* |
| 76 | +# RewriteRule .* - [L] |
| 77 | + |
| 78 | +# Redirect all requests not available on the filesystem to Rails |
| 79 | +# By default the cgi dispatcher is used which is very slow |
| 80 | +# |
| 81 | +# For better performance replace the dispatcher with the fastcgi one |
| 82 | +# |
| 83 | +# Example: |
| 84 | +# RewriteRule ^(.*)$ dispatch.fcgi [QSA,L] |
| 85 | +RewriteEngine On |
| 86 | + |
| 87 | +# If your Rails application is accessed via an Alias directive, |
| 88 | +# then you MUST also set the RewriteBase in this htaccess file. |
| 89 | +# |
| 90 | +# Example: |
| 91 | +# Alias /myrailsapp /path/to/myrailsapp/public |
| 92 | +# RewriteBase /myrailsapp |
| 93 | + |
| 94 | +RewriteRule ^$ index.html [QSA] |
| 95 | +RewriteRule ^([^.]+)$ $1.html [QSA] |
| 96 | +RewriteCond %{REQUEST_FILENAME} !-f |
| 97 | +RewriteRule ^(.*)$ dispatch.cgi [QSA,L] |
| 98 | + |
| 99 | +# In case Rails experiences terminal errors |
| 100 | +# Instead of displaying this message you can supply a file here which will be rendered instead |
| 101 | +# |
| 102 | +# Example: |
| 103 | +# ErrorDocument 500 /500.html |
| 104 | + |
| 105 | +ErrorDocument 500 "<h2>Application error</h2>Rails application failed to start properly" |
| 106 | + |
| 107 | + |
| 108 | +== Debugging Rails |
| 109 | + |
| 110 | +Sometimes your application goes wrong. Fortunately there are a lot of tools that |
| 111 | +will help you debug it and get it back on the rails. |
| 112 | + |
| 113 | +First area to check is the application log files. Have "tail -f" commands running |
| 114 | +on the server.log and development.log. Rails will automatically display debugging |
| 115 | +and runtime information to these files. Debugging info will also be shown in the |
| 116 | +browser on requests from 127.0.0.1. |
| 117 | + |
| 118 | +You can also log your own messages directly into the log file from your code using |
| 119 | +the Ruby logger class from inside your controllers. Example: |
| 120 | + |
| 121 | + class WeblogController < ActionController::Base |
| 122 | + def destroy |
| 123 | + @weblog = Weblog.find(params[:id]) |
| 124 | + @weblog.destroy |
| 125 | + logger.info("#{Time.now} Destroyed Weblog ID ##{@weblog.id}!") |
| 126 | + end |
| 127 | + end |
| 128 | + |
| 129 | +The result will be a message in your log file along the lines of: |
| 130 | + |
| 131 | + Mon Oct 08 14:22:29 +1000 2007 Destroyed Weblog ID #1 |
| 132 | + |
| 133 | +More information on how to use the logger is at http://www.ruby-doc.org/core/ |
| 134 | + |
| 135 | +Also, Ruby documentation can be found at http://www.ruby-lang.org/ including: |
| 136 | + |
| 137 | +* The Learning Ruby (Pickaxe) Book: http://www.ruby-doc.org/docs/ProgrammingRuby/ |
| 138 | +* Learn to Program: http://pine.fm/LearnToProgram/ (a beginners guide) |
| 139 | + |
| 140 | +These two online (and free) books will bring you up to speed on the Ruby language |
| 141 | +and also on programming in general. |
| 142 | + |
| 143 | + |
| 144 | +== Debugger |
| 145 | + |
| 146 | +Debugger support is available through the debugger command when you start your Mongrel or |
| 147 | +Webrick server with --debugger. This means that you can break out of execution at any point |
| 148 | +in the code, investigate and change the model, AND then resume execution! |
| 149 | +You need to install ruby-debug to run the server in debugging mode. With gems, use 'gem install ruby-debug' |
| 150 | +Example: |
| 151 | + |
| 152 | + class WeblogController < ActionController::Base |
| 153 | + def index |
| 154 | + @posts = Post.find(:all) |
| 155 | + debugger |
| 156 | + end |
| 157 | + end |
| 158 | + |
| 159 | +So the controller will accept the action, run the first line, then present you |
| 160 | +with a IRB prompt in the server window. Here you can do things like: |
| 161 | + |
| 162 | + >> @posts.inspect |
| 163 | + => "[#<Post:0x14a6be8 @attributes={\"title\"=>nil, \"body\"=>nil, \"id\"=>\"1\"}>, |
| 164 | + #<Post:0x14a6620 @attributes={\"title\"=>\"Rails you know!\", \"body\"=>\"Only ten..\", \"id\"=>\"2\"}>]" |
| 165 | + >> @posts.first.title = "hello from a debugger" |
| 166 | + => "hello from a debugger" |
| 167 | + |
| 168 | +...and even better is that you can examine how your runtime objects actually work: |
| 169 | + |
| 170 | + >> f = @posts.first |
| 171 | + => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}> |
| 172 | + >> f. |
| 173 | + Display all 152 possibilities? (y or n) |
| 174 | + |
| 175 | +Finally, when you're ready to resume execution, you enter "cont" |
| 176 | + |
| 177 | + |
| 178 | +== Console |
| 179 | + |
| 180 | +You can interact with the domain model by starting the console through <tt>script/console</tt>. |
| 181 | +Here you'll have all parts of the application configured, just like it is when the |
| 182 | +application is running. You can inspect domain models, change values, and save to the |
| 183 | +database. Starting the script without arguments will launch it in the development environment. |
| 184 | +Passing an argument will specify a different environment, like <tt>script/console production</tt>. |
| 185 | + |
| 186 | +To reload your controllers and models after launching the console run <tt>reload!</tt> |
| 187 | + |
| 188 | +== dbconsole |
| 189 | + |
| 190 | +You can go to the command line of your database directly through <tt>script/dbconsole</tt>. |
| 191 | +You would be connected to the database with the credentials defined in database.yml. |
| 192 | +Starting the script without arguments will connect you to the development database. Passing an |
| 193 | +argument will connect you to a different database, like <tt>script/dbconsole production</tt>. |
| 194 | +Currently works for mysql, postgresql and sqlite. |
| 195 | + |
| 196 | +== Description of Contents |
| 197 | + |
| 198 | +app |
| 199 | + Holds all the code that's specific to this particular application. |
| 200 | + |
| 201 | +app/controllers |
| 202 | + Holds controllers that should be named like weblogs_controller.rb for |
| 203 | + automated URL mapping. All controllers should descend from ApplicationController |
| 204 | + which itself descends from ActionController::Base. |
| 205 | + |
| 206 | +app/models |
| 207 | + Holds models that should be named like post.rb. |
| 208 | + Most models will descend from ActiveRecord::Base. |
| 209 | + |
| 210 | +app/views |
| 211 | + Holds the template files for the view that should be named like |
| 212 | + weblogs/index.html.erb for the WeblogsController#index action. All views use eRuby |
| 213 | + syntax. |
| 214 | + |
| 215 | +app/views/layouts |
| 216 | + Holds the template files for layouts to be used with views. This models the common |
| 217 | + header/footer method of wrapping views. In your views, define a layout using the |
| 218 | + <tt>layout :default</tt> and create a file named default.html.erb. Inside default.html.erb, |
| 219 | + call <% yield %> to render the view using this layout. |
| 220 | + |
| 221 | +app/helpers |
| 222 | + Holds view helpers that should be named like weblogs_helper.rb. These are generated |
| 223 | + for you automatically when using script/generate for controllers. Helpers can be used to |
| 224 | + wrap functionality for your views into methods. |
| 225 | + |
| 226 | +config |
| 227 | + Configuration files for the Rails environment, the routing map, the database, and other dependencies. |
| 228 | + |
| 229 | +db |
| 230 | + Contains the database schema in schema.rb. db/migrate contains all |
| 231 | + the sequence of Migrations for your schema. |
| 232 | + |
| 233 | +doc |
| 234 | + This directory is where your application documentation will be stored when generated |
| 235 | + using <tt>rake doc:app</tt> |
| 236 | + |
| 237 | +lib |
| 238 | + Application specific libraries. Basically, any kind of custom code that doesn't |
| 239 | + belong under controllers, models, or helpers. This directory is in the load path. |
| 240 | + |
| 241 | +public |
| 242 | + The directory available for the web server. Contains subdirectories for images, stylesheets, |
| 243 | + and javascripts. Also contains the dispatchers and the default HTML files. This should be |
| 244 | + set as the DOCUMENT_ROOT of your web server. |
| 245 | + |
| 246 | +script |
| 247 | + Helper scripts for automation and generation. |
| 248 | + |
| 249 | +test |
| 250 | + Unit and functional tests along with fixtures. When using the script/generate scripts, template |
| 251 | + test files will be generated for you and placed in this directory. |
| 252 | + |
| 253 | +vendor |
| 254 | + External libraries that the application depends on. Also includes the plugins subdirectory. |
| 255 | + If the app has frozen rails, those gems also go here, under vendor/rails/. |
| 256 | + This directory is in the load path. |
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