--- name: canvas-plugin-init description: Initialize a new Canvas LMS plugin with GUI, API, Worker, and Course Navigation components. --- # Canvas Plugin Initialization Skill This skill provides a standardized way to initialize a new plugin in Canvas LMS. It creates a robust starting point with GUI settings, a backend API, a background worker, and a customizable Course Navigation page with permissions. ## Features - **GUI (User Interface)**: Creates a `settings_partial` that displays a "Hello {{current_user}}" message and basic configuration fields. - **API Backend**: Sets up a controller in `app\/controllers\/api\/v1\/` and registers custom routes. - **Worker Job**: Implements a `Delayed::Job` compatible worker for background tasks. - **Course Navigation**: Adds a sample page to the Course menu (sidebar) that shows "Hello {{username}}, welcome to {{coursename}}". - **System Hooks (Canvas Extensions)**: Demonstrates how to hook into core Canvas logic using `Module#prepend` (example: `Quizzes::Quiz#generate_submission` to track quiz starts). - **Granular Permissions**: Registers a custom permission (`view__sample_page`) that can be configured in the Course\/Account "Permissions" settings. - **Automatic Registration**: Updates `Gemfile.d\/plugins.rb` to ensure the plugin is loaded by Canvas. ## Usage ### 1. Initialize a new plugin Use the `init_plugin.sh` script to scaffold the plugin. ```bash \/bin\/bash .agent\/skills\/canvas-plugin-init\/scripts\/init_plugin.sh ``` Example: ```bash \/bin\/bash .agent\/skills\/canvas-plugin-init\/scripts\/init_plugin.sh hello_world ``` ### 2. File Structure Created - `gems\/plugins\/\/.gemspec`: Gem specification. - `gems\/plugins\/\/lib\/\/engine.rb`: Rails Engine, Permission registration, and Course Navigation extension. - `gems\/plugins\/\/app\/views\/plugins\/__settings.html.erb`: Configuration GUI. - `gems\/plugins\/\/app\/controllers\/api\/v1\/_controller.rb`: API Backend. - `gems\/plugins\/\/app\/controllers\/course_sample_controller.rb`: Course Navigation controller. - `gems\/plugins\/\/app\/views\/\/course_sample\/index.html.erb`: Course Navigation view. - `gems\/plugins\/\/config\/pre_routes.rb`: Custom routes. - `gems\/plugins\/\/lib\/\/worker.rb`: Background Worker. ### 3. Components Overview #### Course Navigation Extensions The skill uses `Course.prepend` to inject a custom tab into the `tabs_available` list. The tab only appears if the user has the registered permission for that course. #### Permissions Permissions are registered via `Permissions.register` in the engine's `to_prepare` block. They automatically appear in the Canvas Permissions UI under the name provided. #### GUI The settings partial is accessible via **Site Admin > Plugins > **. ## Requirements - Canvas LMS environment. - Sufficient permissions to create files in `gems\/plugins\/` and modify `Gemfile.d\/plugins.rb`. ## Troubleshooting ### Missing partial plugins\/__settings **Error:** ``` ActionView::MissingTemplate in Plugins#show Missing partial plugins\/__settings ``` **Cause:** This error occurs when the plugin is registered with a `settings_partial` in the engine.rb file, but the corresponding partial view file doesn't exist. **Solution:** Ensure the settings partial exists at the correct location: ``` gems\/plugins\/\/app\/views\/plugins\/__settings.html.erb ``` The `init_plugin.sh` script automatically creates this file. If you're creating a plugin manually or the file is missing, create it with the following structure: ```erb

<%= t(:_title, " Settings") %><\/h3>
<%= t(:_description, "Configure settings.") %><\/p> <\/div> <%= fields_for :settings do |f| %>

<%= blabel :, :enabled, :en => "Enable Plugin" %><\/td> <%= f.check_box :enabled, :checked => Canvas::Plugin.value_to_boolean(settings[:enabled]) %> <\/td> <\/tr> <\/table> <% end %> ``` Key Points: - The partial filename must start with an underscore (`_`) - The partial must be in the `app\/views\/plugins\/` directory (not `app\/views\/\/`) - The `settings_partial` value in engine.rb should match: `"plugins\/_settings"` (without underscore or .html.erb extension) - Use `fields_for :settings` to ensure form fields are properly namespaced