Add support for Scratch projects (#513)

This introduces the concept of projects of type "scratch" which we're
going to need for the [Experience CS
project](https://github.com/RaspberryPiFoundation/experience-cs).
However, it goes to some pains to ensure that any existing clients of
the API (e.g. `editor-standalone`, `editor-ui`, the admin dashboard in
`editor-api`, etc) will not see a scratch project for now unless they
specifically choose to by adding a `project_type=scratch` query string
parameter.

* [Add default scope to hide scratch
projects](bdf8ccc)
* [Add scratch-only option for project show
endpoint](91e8466)
* [Consistently use strings for
Project#project_type](f442965)
* [Extract string literals -> Project::Types
constants](dfade60)

---------

Co-authored-by: Chris Roos <[email protected]>

Author: floehopper

.rubocop.yml

@@ -20,7 +20,7 @@ GraphQL/ObjectDescription:
     - app/graphql/types/query_type.rb
 
 RSpec/NestedGroups:
-  Max: 4
+  Max: 5
 
 RSpec/DescribeClass:
   Exclude:

app/controllers/api/default_projects_controller.rb

@@ -5,7 +5,7 @@ class DefaultProjectsController < ApiController
     before_action :authorize_user, only: %i[create]
 
     def show
-      data = if params[:type] == 'html'
+      data = if params[:type] == Project::Types::HTML
                html_project
              else
                python_project
@@ -23,7 +23,7 @@ def html
 
     def create
       identifier = PhraseIdentifier.generate
-      @project = Project.new(identifier:, project_type: 'python')
+      @project = Project.new(identifier:, project_type: Project::Types::PYTHON)
       @project.components << Component.new(python_component)
       @project.save
 
@@ -38,7 +38,7 @@ def python_component
 
     def python_project
       {
-        type: 'python',
+        type: Project::Types::PYTHON,
         components: [
           { lang: 'py', name: 'main',
             content: "import turtle\nt = turtle.Turtle()\nt.forward(100)\nprint(\"Oh yeah!\")" }
@@ -53,7 +53,7 @@ def html_project
       CON
 
       {
-        type: 'html',
+        type: Project::Types::HTML,
         components: [
           { lang: 'html', name: 'index', content: },
           { lang: 'css', name: 'style', content: "h1 {\n  color: blue;\n}" },

app/controllers/api/projects_controller.rb

@@ -64,7 +64,7 @@ def verify_lesson_belongs_to_school
     def load_project
       project_loader = ProjectLoader.new(params[:id], [params[:locale]])
       @project = if action_name == 'show'
-                   project_loader.load(include_images: true)
+                   project_loader.load(include_images: true, only_scratch: params[:project_type] == Project::Types::SCRATCH)
                  else
                    project_loader.load
                  end

app/models/filesystem_project.rb

@@ -15,7 +15,7 @@ def self.import_all!
       categorized_files = categorize_files(files, dir)
 
       project_importer = ProjectImporter.new(name: proj_config['NAME'], identifier: proj_config['IDENTIFIER'],
-                                             type: proj_config['TYPE'] || 'python',
+                                             type: proj_config['TYPE'] || Project::Types::PYTHON,
                                              locale: proj_config['LOCALE'] || 'en', **categorized_files)
       project_importer.import!
     end

app/models/project.rb

@@ -1,6 +1,12 @@
 # frozen_string_literal: true
 
 class Project < ApplicationRecord
+  module Types
+    PYTHON = 'python'
+    HTML = 'html'
+    SCRATCH = 'scratch'
+  end
+
   belongs_to :school, optional: true
   belongs_to :lesson, optional: true
   belongs_to :parent, optional: true, class_name: :Project, foreign_key: :remixed_from_id, inverse_of: :remixes
@@ -26,6 +32,8 @@ class Project < ApplicationRecord
   validate :project_with_school_id_has_school_project
   validate :school_project_school_matches_project_school
 
+  default_scope -> { where.not(project_type: Types::SCRATCH) }
+
   scope :internal_projects, -> { where(user_id: nil) }
 
   has_paper_trail(

lib/project_loader.rb

@@ -8,8 +8,9 @@ def initialize(identifier, locales)
     @locales = [*locales, 'en', nil]
   end
 
-  def load(include_images: false)
-    query = Project.where(identifier:, locale: @locales)
+  def load(include_images: false, only_scratch: false)
+    query = only_scratch ? Project.unscoped.where(project_type: Project::Types::SCRATCH) : Project
+    query = query.where(identifier:, locale: @locales)
     query = query.includes(images_attachments: :blob) if include_images
     query.min_by { |project| @locales.find_index(project.locale) }
   end

lib/tasks/seeds_helper.rb

@@ -98,7 +98,7 @@ def create_project(user_id, school, lesson, code = '')
       project.school = school
       project.lesson = lesson
       project.locale = 'en'
-      project.project_type = 'python'
+      project.project_type = Project::Types::PYTHON
       project.components << Component.new({ extension: 'py', name: 'main',
                                             content: code })
     end

spec/concepts/lesson/create_spec.rb

@@ -14,7 +14,7 @@
       school_id: school.id,
       project_attributes: {
         name: 'Hello world project',
-        project_type: 'python',
+        project_type: Project::Types::PYTHON,
         components: [
           { name: 'main.py', extension: 'py', content: 'print("Hello, world!")' }
         ]
@@ -86,7 +86,7 @@
       {
         project_attributes: {
           name: 'Hello world project',
-          project_type: 'python',
+          project_type: Project::Types::PYTHON,
           components: [
             { name: 'main.py', extension: 'py', content: 'print("Hello, world!")' }
           ]

spec/concepts/project/create_spec.rb

@@ -20,7 +20,7 @@
 
       let(:project_hash) do
         {
-          project_type: 'python',
+          project_type: Project::Types::PYTHON,
           components: [{
             name: 'main',
             extension: 'py',

spec/factories/project.rb

@@ -5,7 +5,7 @@
     user_id { SecureRandom.uuid }
     name { Faker::Book.title }
     identifier { "#{Faker::Verb.base}-#{Faker::Verb.base}-#{Faker::Verb.base}" }
-    project_type { 'python' }
+    project_type { Project::Types::PYTHON }
     locale { %w[en es-LA fr-FR].sample }
 
     transient do