Question 1

How to set up CarrierWave for Amazon S3?

Accepted Answer

Install the fog-aws gem, configure fog_credentials and fog_directory in an initializer, and set storage to :fog in your uploader. The README includes detailed examples with AWS-specific permissions and options.

Question 2

CarrierWave vs Active Storage: which should I use?

Accepted Answer

CarrierWave offers more customization, supports multiple ORMs, and has extensive image processing, while Active Storage is Rails-native with built-in direct uploads. Choose CarrierWave for flexibility across frameworks, Active Storage for tighter Rails integration.

Question 3

How do I create image thumbnails with CarrierWave?

Accepted Answer

Include CarrierWave::MiniMagick in your uploader, define a version block with processes like resize_to_fill, and use the url method to access versions. The README shows examples for generating thumbnails from the original file.

Question 4

Can CarrierWave handle multiple file uploads in Rails?

Accepted Answer

Yes, by using mount_uploaders with an array column (e.g., JSON or serialized string), setting multiple: true in the form field, and permitting the attribute as an array in controllers. The README covers SQLite and PostgreSQL setups.

Question 5

How to secure uploads against malicious files?

Accepted Answer

Use extension_allowlist or content_type_allowlist in your uploader to restrict file types, and ensure content_type_allowlist is set to mitigate CVE-2016-3714 for image processing, as emphasized in the security section.

Question 6

Is CarrierWave compatible with non-Rails frameworks like Sinatra?

Accepted Answer

Yes, it works with any Rack-based framework, but integration requires manual setup since it lacks Rails-specific generators and conventions, unlike the seamless ActiveRecord mounting in Rails.

Carrierwave

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