# Active Storage Setup

Configures Active Storage for file uploads with variants and direct uploads.

- Repository: https://github.com/ThibautBaissac/rails_ai_agents (671 stars)
- Category: Data and ML
- License: MIT
- Last updated: 2026-06-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add ThibautBaissac/rails_ai_agents --skill active-storage-setup -g -a claude-code -y`
Codex: `npx skills add ThibautBaissac/rails_ai_agents --skill active-storage-setup -g -a codex -y`
Cursor: `npx skills add ThibautBaissac/rails_ai_agents --skill active-storage-setup -g -a cursor -y`
Gemini CLI: `npx skills add ThibautBaissac/rails_ai_agents --skill active-storage-setup -g -a gemini-cli -y`

## Description

Configures Active Storage for file uploads with variants and direct uploads. Use when adding file uploads, image attachments, document storage, generating thumbnails, or when user mentions Active Storage, file upload, attachments, or image processing. WHEN NOT: Storing data in database columns, external URL references, static assets in the asset pipeline, or simple text/JSON storage.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Active Storage Setup for Rails 8

## Overview

Active Storage handles file uploads in Rails:
- Cloud storage (S3, GCS, Azure) or local disk
- Image variants (thumbnails, resizing)
- Direct uploads from browser
- Polymorphic attachments

## Quick Start

```bash
# Install Active Storage (if not already)
bin/rails active_storage:install
bin/rails db:migrate

# Add image processing
bundle add image_processing
```

## Configuration

### Storage Services

```yaml
# config/storage.yml
local:
  service: Disk
  root: <%= Rails.root.join("storage") %>

test:
  service: Disk
  root: <%= Rails.root.join("tmp/storage") %>

amazon:
  service: S3
  access_key_id: <%= Rails.application.credentials.dig(:aws, :access_key_id) %>
  secret_access_key: <%= Rails.application.credentials.dig(:aws, :secret_access_key) %>
  region: eu-west-1
  bucket: <%= Rails.application.credentials.dig(:aws, :bucket) %>

google:
  service: GCS
  credentials: <%= Rails.root.join("config/gcs-credentials.json") %>
  project: my-project
  bucket: my-bucket
```

### Environment Config

```ruby
# config/environments/development.rb
config.active_storage.service = :local

# config/environments/production.rb
config.active_storage.service = :amazon
```

## Model Attachments

### Single Attachment

```ruby
# app/models/user.rb
class User < ApplicationRecord
  has_one_attached :avatar

  # With variant defaults
  has_one_attached :avatar do |attachable|
    attachable.variant :thumb, resize_to_limit: [100, 100]
    attachable.variant :medium, resize_to_limit: [300, 300]
  end
end
```

### Multiple Attachments

```ruby
# app/models/event.rb
class Event < ApplicationRecord
  has_many_attached :photos

  has_many_attached :documents do |attachable|
    attachable.variant :preview, resize_to_limit: [200, 200]
  end
end
```

## TDD Workflow

The rest: https://github.com/ThibautBaissac/rails_ai_agents/blob/HEAD/.agents/skills/active-storage-setup/SKILL.md