discourse/lib/stylesheet/manager/scss_checker.rb
Alan Guo Xiang Tan 8e3691d537 PERF: Eager load Theme associations in Stylesheet Manager.
Before this change, calling `StyleSheet::Manager.stylesheet_details`
for the first time resulted in multiple queries to the database. This is
because the code was modelled in a way where each `Theme` was loaded
from the database one at a time.

This PR restructures the code such that it allows us to load all the
theme records in a single query. It also allows us to eager load the
required associations upfront. In order to achieve this, I removed the
support of loading multiple themes per request. It was initially added
to support user selectable theme components but the feature was never
completed and abandoned because it wasn't a feature that we thought was
worth building.
2021-06-21 11:06:58 +08:00

36 lines
829 B
Ruby

# frozen_string_literal: true
class Stylesheet::Manager::ScssChecker
def initialize(target, theme_ids)
@target = target.to_sym
@theme_ids = theme_ids
end
def has_scss(theme_id)
!!get_themes_with_scss[theme_id]
end
private
def get_themes_with_scss
@themes_with_scss ||= begin
theme_target = @target.to_sym
theme_target = :mobile if theme_target == :mobile_theme
theme_target = :desktop if theme_target == :desktop_theme
name = @target == :embedded_theme ? :embedded_scss : :scss
results = Theme
.where(id: @theme_ids)
.left_joins(:theme_fields)
.where(theme_fields: {
target_id: [Theme.targets[theme_target], Theme.targets[:common]],
name: name
})
.group(:id)
.size
results
end
end
end