Rails add-on

Ruby LSP Rails is a Ruby LSP add-on that enhances the base Ruby LSP functionality with Rails-specific features. It provides improved code navigation, document symbols for Rails-specific elements, and runtime introspection capabilities.

It communicates with a running Rails instance to provide dynamic information about the application, enabling more accurate and context-aware language server features.

Table of Contents

• Installation
• Runtime Introspection
• Features
  • Document Symbol
    • Active Record Callbacks, Validations, and Associations
    • Active Support Test Cases
  • Go to Controller Action Route
  • Go to Controller Action View
  • Go to Definition
    • Go to Active Record Callback and Validation Definitions
    • Go to Active Record Associations
    • Go to Route Helper Definitions
  • Ruby File Operations
    • Commands
  • Run and Debug
    • Run Tests With Test Explorer
    • Run Tests In The Terminal
    • Debug Tests With VS Code

Installation

The Rails add-on is installed automatically.

Ruby LSP detects Rails projects and installs the Rails add-on for you.

Runtime Introspection

LSP tooling is typically based on static analysis, but ruby-lsp-rails actually communicates with your Rails app for some features.

When Ruby LSP Rails starts, it spawns a rails runner instance which runs server.rb. The add-on communicates with this process over a pipe (i.e. stdin and stdout) to fetch runtime information about the application.

When extension is stopped (e.g. by quitting the editor), the server instance is shut down.

Features

Document Symbol

Document Symbol is a way to represent the structure of a document. They are used to provide a quick overview of the document and to allow for quick navigation.

Ruby LSP already provides document symbols for Ruby files, such as classes, modules, methods, etc. But the Rails add-on provides additional document symbols for Rails specific features.

In VS Code, you can open the document symbols view by pressing Ctrl + Shift + O.

Active Record Callbacks, Validations, and Associations

Navigates between Active Record callbacks, validations, and associations using the Document Symbol feature.

Active Support Test Cases

Navigates between Active Support test cases using the Document Symbol feature.

Go to Controller Action Route

Navigates to the route definition of a controller action using the Code Lens feature.

Go to Controller Action View

Navigates to the view file(s) of a controller action using the Code Lens feature.

Go to Definition

Go to definition is a feature that allows you to navigate to the definition of a symbol.

In VS Code, you can trigger go to definition in 3 different ways:

• Select Go to Definition from the context menu
• F12 on a symbol
• Cmd + Click on a symbol

In the following demos, we will use the Cmd + Click method to trigger go to definition.

Go to Active Record Callback and Validation Definitions

Navigates to the definitions of Active Record callbacks and validations.

Go to Active Record Associations

Navigates to the definitions of Active Record associations.

Go to Route Helper Definitions

Ruby File Operations

The Ruby LSP extension provides a Ruby file operations icon in the Explorer view that can be used to trigger the Rails generate and Rails destroy commands.

Commands

These commands are also available in the Command Palette.

Rails Generate

Rails Destroy

Run and Debug

The Rails add-on provides 3 ways to run and debug ActiveSupport tests using the Code Lens feature.

Run Tests With Test Explorer

Run Tests In The Terminal

Debug Tests With VS Code

Settings

The following setting configures aspects of the Rails add-on. Values shown are the defaults.

// Settings for all add-ons
"rubyLsp.addonSettings": {
   // Settings for the Rails add-on
   "Ruby LSP Rails": {
      // Enable prompt for pending migrations
     "enablePendingMigrationsPrompt": true
   }
 }