Demo Rails app

Demonstration of:

• Ruby on Rails web framework

• Forest Admin web service

• Postgres relational database

• SQLite lightweight database

Prepare

If you use the command asdf to version:

sh asdf global ruby latest asdf global postgres latest

Have Ruby 3?

sh ruby --version

Have Rails 7?

sh gem list rails

Have Postgres 14?

sh postgres --version

Have SQLite 3?

sh sqlite3 --version

New demo

Create a new demo:

sh rails new demo_rails_forest_admin --database=postgresql cd demo_rails_forest_admin git add -A && git commit -am "Run rails new demo_rails_forest_admin --database=postgresql"

If you use asdf then set Ruby and Postgres

sh asdf local ruby latest asdf local postgres latest asdf install git add -A && git commit -am "Add asdf with local ruby latest and local postgres latest"

Verify you can use the Postgres control command pg_ctl:

pg_ctl stop pg_ctl start

Add gem dotenv-rails

Add to Gemfile:

```ruby

Environment variables

gem "dotenv-rails", groups: [:development, :test] ```

Run:

```sh git add -A && git commit -am "Add gem dotenv-rails"

bundle git add -A && git commit -am "Run bundle" ```

Append to file .gitgnore:

```gitignore

Ignore dotenv environment variable file.

/.env ```

Run:

sh git add -A && git commit -am "Add .gitignore rule for dotenv file /.env" touch .env

Create the database access

For a demo app, we prefer to set database access via environment variables.

For a production app, we prefer to set database access via ephemeral controls such as via Hashicorp Vault.

For a naming convention, we prefer explicit database access environment variables:

• The database server name: POSTGRES

• The database server object: USER

• The role identifier: DEMORAILSFOREST_ADMIN

• The role attribute: USERNAME or PASSWORD

• The word FOR and the runtime environment: DEVELOPMENT or TEST or PRODUCTION

For our password, we prefer to generate a strong random password, such as a strong random 32-digit number:

sh printf "%s\n" $(LC_ALL=C < /dev/urandom tr -dc '[:digit:]' | head -c32)

Edit file .env to set the database access enviornment variables and the generated passwords:

```sh POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORDEVELOPMENT=demorailsforestadmin POSTGRESUSERDEMORAILSFORESTADMINPASSWORDFOR_DEVELOPMENT=11053635016261456248726591454979

POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORTEST=demorailsforestadmin POSTGRESUSERDEMORAILSFORESTADMINPASSWORDFOR_TEST=82138770260839801404701988766919

POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORPRODUCTION=demorailsforestadmin POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFOR_PRODUCTION=59637922222719767183438989864425 ```

Create the database role and enter the password for development:

sh createuser --username=postgres --pwprompt --createdb demo_rails_forest_admin

Configure the database access

Edit file config/database.yml to add each section's username and password:

```yaml development: <<: *default database: demorailsforestadmindevelopment username: <%= ENV["POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORDEVELOPMENT"] %> password: <%= ENV["POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORDEVELOPMENT"] %> …

test: <<: *default database: demorailsforestadmintest username: <%= ENV["POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORTEST"] %> password: <%= ENV["POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORTEST"] %> …

production: <<: *default database: demorailsforestadminproduction username: <%= ENV["POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORPRODUCTION"] %> password: <%= ENV["POSTGRESUSERDEMORAILSFORESTADMINUSERNAMEFORPRODUCTION"] %> … ```

RUn:

sh git add -A && git commit -am "Add database access usernames and passwords" Run:

Pepare the database

sh bin/rails db:prepare

Output should include:

sh Created database 'demo_rails_forest_admin_development' Created database 'demo_rails_forest_admin_test'

Launch the server

Launch the Rails Puma server:

sh bin/rails server

Output should include:

sh Puma starting in single mode... * Listening on http://127.0.0.1:3000

Browse http://127.0.0.1:3000 and you should see the Rails welcome page.

Enable Postgres UUID primary keys

Enable Postgres UUID primary keys and their functions via pgcrypto:

sh bin/rails generate migration EnableExtensionPgcrypto

Edit file db/migration/*_enable_extension_pgcrypto:

ruby class EnableExtensionPgcrypto < ActiveRecord::Migration[7.0] def change enable_extension 'pgcrypto' end end

sh git add -A && git commit -am "Add db migration to enable extension pgcrypto, then migrate" bin/rails db:migrate git add -A && git commit -am "Run rails db:migrate"

Create file config/initializers/generators.rb:

ruby Rails.application.config.generators do |g| g.orm :active_record, primary_key_type: :uuid end

sh git add -A && git commit -am "Add generators ORM primary key type UUID"

Install ActiveStorage

Add to Gemfile:

ruby gem "image_processing", ">= 1.2"

Run:

```sh git add -A && git commit -am "Add gem image_processing"

bundle git add -A && git commit -am "Run bundle"

bin/rails activestorage:install git add -A && git commit -am "Run rails activestorage:install"

bin/rails db:migrate git add -A && git commit -am "Run rails db:migrate" ```

The project now has a new database migration file db/migrate/*_create_active_storage_tables.active_storage.rb.

Add scaffolds for users, groups, memberships

Generate scaffolds for our demo resources, which are users, groups, memberships.

```sh bin/rails generate scaffold User name:string description:string bin/rails db:migrate git add -A && git commit -am "Run rails generate scaffold User, then db:migrate"

bin/rails generate scaffold Group name:string description:string bin/rails db:migrate git add -A && git commit -am "Run rails generate scaffold Group, then db:migrate"

bin/rails generate scaffold Membership group:references user:references bin/rails db:migrate git add -A && git commit -am "Run rails generate scaffold Membership, then db:migrate" ```

Edit file app/models/user.rb

ruby class User < ApplicationRecord has_many :memberships has_many :groups, through: :memberships end

sh git add -A && git commit -am "Add user associations"

Edit file app/models/group.rb

ruby class Group < ApplicationRecord has_many :memberships has_many :users, through: :memberships end

sh git add -A && git commit -am "Add group associations"

Add root route

Edit file config/routes:

ruby root "users#index"

sh git add -A && git commit -am "Add root route"

Add Devise authentication

Add to Gemfile:

```ruby

Devise authentication

gem "devise" ```

```sh git add -A && git commit -am "Add gem devise"

bundle git add -A && git commit -am "Run bundle"

rails generate devise:install git add -A && git commit -am "Run rails generate devise:install"

rails generate devise User git add -A && git commit -am "Run rails generate generate devise User"

rails db:migrate git add -A && git commit -am "Run rails db:migrate" ```