---
title: Interesting Rails Conventions
permalink: interesting-rails-conventions
date: 2023-12-01T12:06:08-05:00
tags: rails
---

As a noob in programming in Ruby on Rails, I feel like there's a lot to learn.
Unfortunately Intellisense doesn't work great leading to harder discoverability.
Convention over configuration is great, but only if you already know that
convention. Here's some miscellaneous things that I found interesting while
reading the Ruby on Rails guides (for v7.1.2).

Disclaimer: I'm still very new to this, so if anything here is wrong please let
me know!

## Notes:

- In regex, use `\A` and `\z` to indicate the start and end of the string. [^a]
- `has_many :books, dependent: :destroy` [^b]
- Use `has_and_belongs_to_many` to build an implicit join table easily,
  otherwise `has_many :through`
- Symbol vs String: Use Symbol when the identity of it matters, use String when
  contents matter
- `-> { method }` or `->(args) { method(args)}` is a lambda
- Metaprogramming makes things confusing. As a beginner, try not to touch it if
  possible (and to keep code readable).
- ActiveJob is really cool
- You can use `<%= method %>` erb-style interpolation in YAML files, somehow. I
  should figure out how.
- An ActiveStorage "file" is called an attachment
- You should periodically purge unattached uploads [^c]

## Full text:

[^a]:
    use `\A` and `\z` to match the start and end of the string, `^` and `$`
    match the start/end of a line. Due to frequent misuse of `^` and `$`, you
    need to pass the multiline: true option in case you use any of these two
    anchors in the provided regular expression. In most cases, you should be
    using `\A` and `\z`.

[^b]:

```rb
class Author < ApplicationRecord
  has_many :books, dependent: :destroy
end

class Book < ApplicationRecord
  belongs_to :author
end

```

[^c]:

```rb
namespace :active_storage do
  desc "Purges unattached Active Storage blobs. Run regularly."
  task purge_unattached: :environment do
    ActiveStorage::Blob.unattached.where(created_at: ..2.days.ago).find_each(&:purge_later)
  end
end
```

The query generated by ActiveStorage::Blob.unattached can be slow and
potentially disruptive on applications with larger databases.