| 1 | == Welcome to Rails |
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| 2 | |
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| 3 | Rails is a web-application and persistence framework that includes everything |
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| 4 | needed to create database-backed web-applications according to the |
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| 5 | Model-View-Control pattern of separation. This pattern splits the view (also |
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| 6 | called the presentation) into "dumb" templates that are primarily responsible |
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| 7 | for inserting pre-built data in between HTML tags. The model contains the |
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| 8 | "smart" domain objects (such as Account, Product, Person, Post) that holds all |
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| 9 | the business logic and knows how to persist themselves to a database. The |
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| 10 | controller handles the incoming requests (such as Save New Account, Update |
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| 11 | Product, Show Post) by manipulating the model and directing data to the view. |
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| 12 | |
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| 13 | In Rails, the model is handled by what's called an object-relational mapping |
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| 14 | layer entitled Active Record. This layer allows you to present the data from |
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| 15 | database rows as objects and embellish these data objects with business logic |
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| 16 | methods. You can read more about Active Record in |
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| 17 | link:files/vendor/rails/activerecord/README.html. |
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| 18 | |
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| 19 | The controller and view are handled by the Action Pack, which handles both |
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| 20 | layers by its two parts: Action View and Action Controller. These two layers |
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| 21 | are bundled in a single package due to their heavy interdependence. This is |
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| 22 | unlike the relationship between the Active Record and Action Pack that is much |
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| 23 | more separate. Each of these packages can be used independently outside of |
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| 24 | Rails. You can read more about Action Pack in |
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| 25 | link:files/vendor/rails/actionpack/README.html. |
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| 26 | |
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| 27 | |
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| 28 | == Getting started |
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| 29 | |
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| 30 | 1. Start the web server: <tt>ruby script/server</tt> (run with --help for options) |
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| 31 | 2. Go to http://localhost:3000/ and get "Welcome aboard: You’re riding the Rails!" |
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| 32 | 3. Follow the guidelines to start developing your application |
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| 33 | |
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| 34 | |
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| 35 | == Web servers |
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| 36 | |
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| 37 | Rails uses the built-in web server in Ruby called WEBrick by default, so you don't |
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| 38 | have to install or configure anything to play around. |
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| 39 | |
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| 40 | If you have lighttpd installed, though, it'll be used instead when running script/server. |
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| 41 | It's considerably faster than WEBrick and suited for production use, but requires additional |
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| 42 | installation and currently only works well on OS X/Unix (Windows users are encouraged |
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| 43 | to start with WEBrick). We recommend version 1.4.11 and higher. You can download it from |
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| 44 | http://www.lighttpd.net. |
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| 45 | |
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| 46 | If you want something that's halfway between WEBrick and lighttpd, we heartily recommend |
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| 47 | Mongrel. It's a Ruby-based web server with a C-component (so it requires compilation) that |
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| 48 | also works very well with Windows. See more at http://mongrel.rubyforge.org/. |
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| 49 | |
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| 50 | But of course its also possible to run Rails with the premiere open source web server Apache. |
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| 51 | To get decent performance, though, you'll need to install FastCGI. For Apache 1.3, you want |
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| 52 | to use mod_fastcgi. For Apache 2.0+, you want to use mod_fcgid. |
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| 53 | |
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| 54 | See http://wiki.rubyonrails.com/rails/pages/FastCGI for more information on FastCGI. |
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| 55 | |
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| 56 | == Example for Apache conf |
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| 57 | |
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| 58 | <VirtualHost *:80> |
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| 59 | ServerName rails |
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| 60 | DocumentRoot /path/application/public/ |
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| 61 | ErrorLog /path/application/log/server.log |
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| 62 | |
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| 63 | <Directory /path/application/public/> |
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| 64 | Options ExecCGI FollowSymLinks |
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| 65 | AllowOverride all |
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| 66 | Allow from all |
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| 67 | Order allow,deny |
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| 68 | </Directory> |
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| 69 | </VirtualHost> |
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| 70 | |
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| 71 | NOTE: Be sure that CGIs can be executed in that directory as well. So ExecCGI |
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| 72 | should be on and ".cgi" should respond. All requests from 127.0.0.1 go |
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| 73 | through CGI, so no Apache restart is necessary for changes. All other requests |
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| 74 | go through FCGI (or mod_ruby), which requires a restart to show changes. |
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| 75 | |
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| 76 | |
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| 77 | == Debugging Rails |
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| 78 | |
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| 79 | Have "tail -f" commands running on both the server.log, production.log, and |
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| 80 | test.log files. Rails will automatically display debugging and runtime |
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| 81 | information to these files. Debugging info will also be shown in the browser |
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| 82 | on requests from 127.0.0.1. |
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| 83 | |
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| 84 | |
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| 85 | == Breakpoints |
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| 86 | |
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| 87 | Breakpoint support is available through the script/breakpointer client. This |
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| 88 | means that you can break out of execution at any point in the code, investigate |
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| 89 | and change the model, AND then resume execution! Example: |
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| 90 | |
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| 91 | class WeblogController < ActionController::Base |
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| 92 | def index |
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| 93 | @posts = Post.find_all |
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| 94 | breakpoint "Breaking out from the list" |
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| 95 | end |
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| 96 | end |
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| 97 | |
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| 98 | So the controller will accept the action, run the first line, then present you |
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| 99 | with a IRB prompt in the breakpointer window. Here you can do things like: |
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| 100 | |
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| 101 | Executing breakpoint "Breaking out from the list" at .../webrick_server.rb:16 in 'breakpoint' |
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| 102 | |
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| 103 | >> @posts.inspect |
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| 104 | => "[#<Post:0x14a6be8 @attributes={\"title\"=>nil, \"body\"=>nil, \"id\"=>\"1\"}>, |
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| 105 | #<Post:0x14a6620 @attributes={\"title\"=>\"Rails you know!\", \"body\"=>\"Only ten..\", \"id\"=>\"2\"}>]" |
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| 106 | >> @posts.first.title = "hello from a breakpoint" |
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| 107 | => "hello from a breakpoint" |
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| 108 | |
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| 109 | ...and even better is that you can examine how your runtime objects actually work: |
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| 110 | |
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| 111 | >> f = @posts.first |
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| 112 | => #<Post:0x13630c4 @attributes={"title"=>nil, "body"=>nil, "id"=>"1"}> |
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| 113 | >> f. |
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| 114 | Display all 152 possibilities? (y or n) |
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| 115 | |
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| 116 | Finally, when you're ready to resume execution, you press CTRL-D |
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| 117 | |
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| 118 | |
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| 119 | == Console |
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| 120 | |
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| 121 | You can interact with the domain model by starting the console through script/console. |
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| 122 | Here you'll have all parts of the application configured, just like it is when the |
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| 123 | application is running. You can inspect domain models, change values, and save to the |
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| 124 | database. Starting the script without arguments will launch it in the development environment. |
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| 125 | Passing an argument will specify a different environment, like <tt>script/console production</tt>. |
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| 126 | |
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| 127 | To reload your controllers and models after launching the console run <tt>reload!</tt> |
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| 128 | |
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| 129 | |
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| 130 | |
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| 131 | == Description of contents |
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| 132 | |
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| 133 | app |
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| 134 | Holds all the code that's specific to this particular application. |
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| 135 | |
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| 136 | app/controllers |
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| 137 | Holds controllers that should be named like weblog_controller.rb for |
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| 138 | automated URL mapping. All controllers should descend from |
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| 139 | ActionController::Base. |
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| 140 | |
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| 141 | app/models |
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| 142 | Holds models that should be named like post.rb. |
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| 143 | Most models will descend from ActiveRecord::Base. |
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| 144 | |
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| 145 | app/views |
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| 146 | Holds the template files for the view that should be named like |
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| 147 | weblog/index.rhtml for the WeblogController#index action. All views use eRuby |
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| 148 | syntax. This directory can also be used to keep stylesheets, images, and so on |
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| 149 | that can be symlinked to public. |
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| 150 | |
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| 151 | app/helpers |
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| 152 | Holds view helpers that should be named like weblog_helper.rb. |
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| 153 | |
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| 154 | app/apis |
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| 155 | Holds API classes for web services. |
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| 156 | |
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| 157 | config |
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| 158 | Configuration files for the Rails environment, the routing map, the database, and other dependencies. |
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| 159 | |
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| 160 | components |
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| 161 | Self-contained mini-applications that can bundle together controllers, models, and views. |
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| 162 | |
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| 163 | db |
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| 164 | Contains the database schema in schema.rb. db/migrate contains all |
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| 165 | the sequence of Migrations for your schema. |
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| 166 | |
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| 167 | lib |
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| 168 | Application specific libraries. Basically, any kind of custom code that doesn't |
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| 169 | belong under controllers, models, or helpers. This directory is in the load path. |
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| 170 | |
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| 171 | public |
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| 172 | The directory available for the web server. Contains subdirectories for images, stylesheets, |
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| 173 | and javascripts. Also contains the dispatchers and the default HTML files. |
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| 174 | |
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| 175 | script |
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| 176 | Helper scripts for automation and generation. |
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| 177 | |
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| 178 | test |
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| 179 | Unit and functional tests along with fixtures. |
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| 180 | |
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| 181 | vendor |
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| 182 | External libraries that the application depends on. Also includes the plugins subdirectory. |
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| 183 | This directory is in the load path. |
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