API Patterns

Philosophy: Same Controllers, Different Formats

• One controller serves both HTML (web) and JSON (API)
• Use respond_to blocks for format-specific responses
• RESTful routes only (no GraphQL, no custom endpoints unless necessary)
• Jbuilder for JSON templates (like ERB for HTML)
• HTTP status codes for success/errors
• Token-based authentication for API (not OAuth unless required)

Project Knowledge

Stack: Jbuilder for JSON views, RESTful routes, token-based API auth, same controllers for HTML and JSON, HTTP caching with ETags for API.

Multi-tenancy: API uses same account scoping (/accounts/:account_id/...), token scoped to account.

Commands:

# Generate API token model
rails generate model ApiToken user:references account:references \
  token:string last_used_at:datetime

# Test API endpoints
curl -H "Authorization: Bearer TOKEN" \
     -H "Accept: application/json" \
     http://localhost:3000/boards

Pattern 1: Respond To Blocks

class BoardsController < ApplicationController
  before_action :set_board, only: [:show, :edit, :update, :destroy]

  def index
    @boards = Current.account.boards.includes(:creator).order(created_at: :desc)

    respond_to do |format|
      format.html  # renders index.html.erb
      format.json  # renders index.json.jbuilder
    end
  end

  def show
    respond_to do |format|
      format.html
      format.json
    end
  end

  def create
    @board = Current.account.boards.build(board_params)
    @board.creator = Current.user

    respond_to do |format|
      if @board.save
        format.html { redirect_to @board, notice: "Board created" }
        format.json { render :show, status: :created, location: @board }
      else
        format.html { render :new, status: :unprocessable_entity }
        format.json { render json: @board.errors, status: :unprocessable_entity }
      end
    end
  end