Configurable Cache-Control Headers in Marten for Environment-Specific Asset Management

[bruno-berchielli]

Currently, if you use Marten::Middleware::AssetServing, this setting is always applied to the headers response.headers[:"Cache-Control"] = "private, max-age=3600". However, ideally, we should be able to set this value per environment.

For example, for my development environment, I would like to set config.assets.max_age = 0 to make the browser always request the latest file.

I'm open to submitting a PR if you think this is a valid point.

[ellmetha]

Hey! 👋

The ability to set the max-age for the Cache-Control header is definitely something that should be added. I'll create an issue so that we don't forget to add this (edit - added in #221). Otherwise, yes - a PR adding this would be much appreciated! 🙏 😊

I'm interested to know, is there a particular reason why you're considering using this middleware in your development setup?

I am asking because the Marten::Middleware::AssetServing middleware is really intended to be used in production environments. Although you can decide to use it in development, it is not really necessary given that Marten offers assets serving (and media files serving) in development through the use of a special handler. In this light, each generated Marten project defines a special route for serving assets in development environments. This will usually look something like this in the config/routes.cr file:

Marten.routes.draw do
  # Other routes...

  if Marten.env.development?
    path "#{Marten.settings.assets.url}<path:path>", Marten::Handlers::Defaults::Development::ServeAsset, name: "asset"
    path "#{Marten.settings.media_files.url}<path:path>", Marten::Handlers::Defaults::Development::ServeMediaFile, name: "media_file"
  end
end

This is all that's needed to serve assets in development. 🙂

Ideally, the Marten::Middleware::AssetServing middleware should only be added to the middleware setting in production environments. For example:

Marten.configure :production do |config|
  config.middleware.unshift(Marten::Middleware::AssetServing)
end