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Diffstat (limited to 'guides/source/engines.md')
| -rw-r--r-- | guides/source/engines.md | 47 |
1 files changed, 25 insertions, 22 deletions
diff --git a/guides/source/engines.md b/guides/source/engines.md index 3b1588b75a..359796b1ff 100644 --- a/guides/source/engines.md +++ b/guides/source/engines.md @@ -150,7 +150,7 @@ When you include the engine into an application later on, you will do so with this line in the Rails application's `Gemfile`: ```ruby -gem 'blorgh', path: "vendor/engines/blorgh" +gem 'blorgh', path: 'engines/blorgh' ``` Don't forget to run `bundle install` as usual. By specifying it as a gem within @@ -239,6 +239,27 @@ NOTE: The `ApplicationController` class inside an engine is named just like a Rails application in order to make it easier for you to convert your applications into engines. +NOTE: Because of the way that Ruby does constant lookup you may run into a situation +where your engine controller is inheriting from the main application controller and +not your engine's application controller. Ruby is able to resolve the `ApplicationController` constant, and therefore the autoloading mechanism is not triggered. See the section [When Constants Aren't Missed](autoloading_and_reloading_constants.html#when-constants-aren-t-missed) of the [Autoloading and Reloading Constants](autoloading_and_reloading_constants.html) guide for further details. The best way to prevent this from +happening is to use `require_dependency` to ensure that the engine's application +controller is loaded. For example: + +``` ruby +# app/controllers/blorgh/articles_controller.rb: +require_dependency "blorgh/application_controller" + +module Blorgh + class ArticlesController < ApplicationController + ... + end +end +``` + +WARNING: Don't use `require` because it will break the automatic reloading of classes +in the development environment - using `require_dependency` ensures that classes are +loaded and unloaded in the correct manner. + Lastly, the `app/views` directory contains a `layouts` folder, which contains a file at `blorgh/application.html.erb`. This file allows you to specify a layout for the engine. If this engine is to be used as a stand-alone engine, then you @@ -639,7 +660,7 @@ However, because you are developing the `blorgh` engine on your local machine, you will need to specify the `:path` option in your `Gemfile`: ```ruby -gem 'blorgh', path: "/path/to/blorgh" +gem 'blorgh', path: 'engines/blorgh' ``` Then run `bundle` to install the gem. @@ -670,7 +691,7 @@ pre-defined path which may be customizable. The engine contains migrations for the `blorgh_articles` and `blorgh_comments` table which need to be created in the application's database so that the engine's models can query them correctly. To copy these migrations into the -application use this command: +application run the following command from the `test/dummy` directory of your Rails engine: ```bash $ rake blorgh:install:migrations @@ -843,28 +864,10 @@ above the "Title" output inside `app/views/blorgh/articles/show.html.erb`: ```html+erb <p> <b>Author:</b> - <%= @article.author %> + <%= @article.author.name %> </p> ``` -By outputting `@article.author` using the `<%=` tag, the `to_s` method will be -called on the object. By default, this will look quite ugly: - -``` -#<User:0x00000100ccb3b0> -``` - -This is undesirable. It would be much better to have the user's name there. To -do this, add a `to_s` method to the `User` class within the application: - -```ruby -def to_s - name -end -``` - -Now instead of the ugly Ruby object output, the author's name will be displayed. - #### Using a Controller Provided by the Application Because Rails controllers generally share code for things like authentication |