Lato CMS

Manage application content on Lato projects.

Installation

Add required dependencies to your application's Gemfile:

# Use lato as application panel
gem "lato"
gem "lato_cms"

Install gem and run required tasks:

$ bundle
$ rails lato_cms:install:application
$ rails lato_cms:install:migrations
$ rails db:migrate

Mount lato users routes on the config/routes.rb file:

Rails.application.routes.draw do
  mount LatoCms::Engine => "/lato-users"
  # ....
end

Import Lato Scss on app/assets/stylesheets/application.scss file:

@import 'lato_cms/application';

// ....

Import Lato Users Js on app/javascript/application.js file:

import "lato_cms/application";

// ....

Media URLs

By default a media URL is an Active Storage redirect URL: Rails answers 302 with a signed address that expires. On a remote service (S3 and friends) that is what you want — the file then comes from the service itself.

On a disk service it is the wrong trade: the redirect costs a second request, and its target is served private, must-revalidate, so no browser, proxy or CDN can keep it. A video of a few dozen MB is then downloaded again on every visit, from a thread of your app server. Switch the mode:

LatoCms.configure do |config|
  config.media_url_mode = :proxy
end

Media URLs (the blob and every variant) then point at Active Storage's proxy controller: no redirect, and Cache-Control: public, immutable, which a cache in front of the app can actually use. The address carries the signature of the blob, so a replaced file is a different address and can never be served stale.

⚠️ :proxy needs something in front that splits byte ranges — nginx with slice, or a CDN that does the same. Active Storage's proxy controller serves one range at a time, holding it in memory, and answers 416 to anything above streaming_chunk_max_size (100 MB by default). A <video> opens with Range: bytes=0-, that is the whole file: above that size the browser reads the 416 as "format not supported", and below it the app loads tens of MB into memory per request. With slices of 1 MB neither happens. Without such a front, stay on :redirect.

Both modes ask for an inline disposition: a media of the library is content to show, and the default for a video would otherwise turn opening its address into a download.

Development

Clone repository, install dependencies, run migrations and start:

$ git clone https://github.com/Lato-GAM/lato_cms
$ cd lato_cms
$ bundle
$ rails db:migrate
$ rails db:seed
$ foreman start -f Procfile.dev

Publish

$ ruby ./bin/publish.rb

License

The gem is available as open source under the terms of the MIT License.