With a standard S3 configuration:
AWS_ACCESS_KEY_ID: [AWS ID]
AWS_BUCKET: [bucket name]
AWS_REGION: [region]
AWS_SECRET_ACCESS_KEY: [secret]
I can upload a file to S3 (using direct upload) with this Rails 5.2 code (only relevant code shown):
form.file_field :my_asset, direct_upload: true
This will effectively put my asset in the root of my S3 bucket, upon submitting the form.
How can I specify a prefix (e.g. "development/", so that I can mimic a folder on S3)?
2022 update: as of Rails 6.1 (check this commit - Allow providing a custom key per blob), this is actually supported:
user.avatar.attach(key: "avatars/#{user.id}.jpg",
io:,
content_type: "image/jpeg",
filename: "avatar.jpg")